In economics and finance, present value (PV), also known as present discounted value, is the value of an expected income stream determined as of the date of valuation. The present value is always less than or equal to the future value because money has interestearning potential, a characteristic referred to as the time value of money, except during times of negative interest rates, when the present value will be more than the future value.^{[1]} Time value can be described with the simplified phrase, "A dollar today is worth more than a dollar tomorrow". Here, 'worth more' means that its value is greater. A dollar today is worth more than a dollar tomorrow because the dollar can be invested and earn a day's worth of interest, making the total accumulate to a value more than a dollar by tomorrow. Interest can be compared to rent.^{[2]} Just as rent is paid to a landlord by a tenant without the ownership of the asset being transferred, interest is paid to a lender by a borrower who gains access to the money for a time before paying it back. By letting the borrower have access to the money, the lender has sacrificed the exchange value of this money, and is compensated for it in the form of interest. The initial amount of the borrowed funds (the present value) is less than the total amount of money paid to the lender.
Present value calculations, and similarly future value calculations, are used to value loans, mortgages, annuities, sinking funds, perpetuities, bonds, and more. These calculations are used to make comparisons between cash flows that don’t occur at simultaneous times,^{[1]} since time dates must be consistent in order to make comparisons between values. When deciding between projects in which to invest, the choice can be made by comparing respective present values of such projects by means of discounting the expected income streams at the corresponding project interest rate, or rate of return. The project with the highest present value, i.e. that is most valuable today, should be chosen.
YouTube Encyclopedic

1/5Views:717 797208 98073 35360 370427 600

✪ Introduction to present value  Interest and debt  Finance & Capital Markets  Khan Academy

✪ 2 Easy Steps: Present Value and Future Value Calculation with Present Value Formula

✪ Finding Present Value and Future Value

✪ How to Calculate Present Value  Episode 42

✪ Net Present Value (NPV)
Transcription
We'll now learn about what is arguably the most useful concept in finance, and that's called the present value. And if you know the present value, then it's very easy to understand the net present value and the discounted cash flow and the internal rate of return. And we'll eventually learn all of those things. But the present value. What does that mean? Present value. So let's do a little exercise. I could pay you $100 today. So let's say today, I could pay you $100. Or, and it's up to you, in one year I will pay you I don't know let's say in a year I agree to pay you $110. And my question to you and this is a fundamental question of finance, everything will build upon this is which one would you prefer? And this is guaranteed. I guarantee you. I'm either going to pay you $100 today, and there's no risk, even if I get hit by a truck or whatever. This is going to happen. The U.S. government, if the earth exists, we will pay you $110 in one year. It is guaranteed. So there's no risk here. So it's just the notion of you're definitely going to get $100 today in your hand, or you're definitely going to get $110 one year from now. So how do you compare the two? And this is where present value comes in. What if there were a way to say, well what is $110, a guaranteed $110, in the future? What if there were a way to say, how much is that worth today? How much is that worth in today's terms? So let's do a little thought experiment. Let's say that you could put money in the bank. And these days banks are kind of risky. But let's say you could put it in the safest bank in the world. Let's say you , although someone would debate, you put it in government treasuries. Which are considered riskfree, because the U.S. government, the Treasury, can always indirectly print more money. We'll one day do a whole thing on the money supply. But at the end of the day, the U.S. government has the rights on the printing press, et cetera. It's more complicated than that. But for those purposes, we assume that with the U.S. Treasury, which essentially is you're lending money to the U.S. government, that it's riskfree. So let's say today I could give you $100 and that you could invest it at 5% riskfree. And then in a year from now, how much would that be worth, in a year? That would be worth $105 in one year. Actually let me write the $110 over here. So this was a good way of thinking about it. You're like, OK, instead of taking the money from Sal a year from now and getting $110, if I were to take $100 today and put it in something riskfree, in a year I would have $105. So assuming I don't have to spend the money today, this is a better situation to be in, right? If I take the money today, and riskfree invest it at 5%, I'm going to end up with $105 in a year. Instead, if you just tell me, Sal, just give me the money in a year give me $110 you're going to end up with more money in a year, right? You're going to end up with $110. And that is actually the right way to think about it. And remember, and I keep saying it over and over again, everything I'm talking about, it's critical that we're talking about riskfree. Once you introduce risk, then we have to start introducing different interest rates and probabilities. And we'll get to that eventually. But I want to just give the purest example right now. So already you've made the decision. But we still don't know what the present value was. So to some degree when you took this $100 and you said well if I lend it to the government, or if I lend it to a riskfree bank at 5%, in a year they'll give me $105. This $105 is a way of saying what is the oneyear value of $100 today? What is the oneyearout value of $100 today? So what if we wanted to go in the other direction? If we have a certain amount of money and we want to figure out today's value, what could we do? Well, to go from here to here, what did we do? We essentially took $100 and we multiplied by what did we multiply by 1 plus 5%. So that's 1.05. So to go the other way, to say how much money, if I were to grow it by 5%, would end up being $110? We'll just divide by 1.05. And then we will get the present value. And the notation is PV. We'll get the present value of $110 a year from now. So the present value of $110, let's say in 2009. It's currently 2008. I don't know what year you're watching this video in. Hopefully people will be watching this in the next millennia. But the present value of $110 in 2009, assuming right now it's 2008, a year from now, is equal to $110 divided by 1.05. And let's take out this calculator, which is probably overkill for this problem. Let me clear everything. OK so I want to do 110 divided by 1.05 is equal to let's just round so it equals $104.76. So the present value of $110 a year from now, if we assume that we could invest money riskfree at 5%, if we were to get it today  let me do it in a different color just to fight the monotony the present value is equal to $104.76. Another way to kind of just talk about this is to get the present value of $110 a year from now, we discounted the value by a discount rate. And the discount rate is this. Right here we grew the money by, you could say, our yield. A 5% yield or our interest. Here we're discounting the money, because we're going backwards in time. We're going from yearout to the present. And so this is our yield. To compound the amount of money we invest, we multiply the amount we invest times 1 plus the yield. Then to discount money in the future to the present, we divided by 1 plus the discount rate so this is a 5% discount rate to get its present value. So what does this tell us? This tells us if someone's willing to pay $110, assuming this 5% remember this is a critical assumption. This tells us that if I tell you I'm willing to pay you $110 a year from now, and you could get 5% so you could kind of say that 5% is your discount rate riskfree that you should be willing to take today's money, if today I'm willing to give you more than the present value. So if this comparison were let me clear all of this, let me just scroll down so let's say that today, 1 year. So we figured out that $110 a year from now, its present value is equal to so the present value of that $110 is equal to $104.76. And that's because I used a 5% discount rate, and that's a key assumption. This is a dollar sign. I know it's hard to read. What this tells you is that, if your choice was between $110 a year from now and $100 today, you should take the $110 a year from now. Why is that? Because its present value is worth more than $100. However, if I were to offer you $110 a year from now or $105 today. This, the $105 today, would be the better choice. Because its present value , right, $105 today, you don't have to discount it . It's today. Its present value is itself. $105 today is worth more than the present value of $110, which is $104.76. Another way to think about it is, I could take this $105 to the bank let's assume I have a riskfree bank get 5% on it. And then I would have what would I end up with I'd end up with 105 times 1.05. Equal to $110.25. So a year from now, I'd be better off by $0.25. And I'd have the joy of being able to touch my money for a year, which is hard to quantify, so we leave out of the equation. Anyway, I'll see you in the next video.
Contents
Years' purchase
The traditional method of valuing future income streams as a present capital sum is to multiply the average expected annual cashflow by a multiple, known as "years' purchase". For example, in selling to a third party a property leased to a tenant under a 99year lease at a rent of $10,000 per annum, a deal might be struck at "20 years' purchase", which would value the lease at 20 * $10,000, i.e. $200,000. This equates to a present value discounted in perpetuity at 5%. For a riskier investment the purchaser would demand to pay a lower number of years' purchase. This was the method used for example by the English crown in setting resale prices for manors seized at the Dissolution of the Monasteries in the early 16th century. The standard usage was 20 years' purchase.^{[3]}
Background
If offered a choice between $100 today or $100 in one year, and there is a positive real interest rate throughout the year, ceteris paribus, a rational person will choose $100 today. This is described by economists as time preference. Time preference can be measured by auctioning off a risk free security—like a US Treasury bill. If a $100 note with a zero coupon, payable in one year, sells for $80 now, then $80 is the present value of the note that will be worth $100 a year from now. This is because money can be put in a bank account or any other (safe) investment that will return interest in the future.
An investor who has some money has two options: to spend it right now or to save it. But the financial compensation for saving it (and not spending it) is that the money value will accrue through the compound interest that he or she will receive from a borrower (the bank account in which he has the money deposited).
Therefore, to evaluate the real value of an amount of money today after a given period of time, economic agents compound the amount of money at a given (interest) rate. Most actuarial calculations use the riskfree interest rate which corresponds to the minimum guaranteed rate provided by a bank's saving account for example, assuming no risk of default by the bank to return the money to the account holder on time. To compare the change in purchasing power, the real interest rate (nominal interest rate minus inflation rate) should be used.
The operation of evaluating a present value into the future value is called a capitalization (how much will $100 today be worth in 5 years?). The reverse operation—evaluating the present value of a future amount of money—is called a discounting (how much will $100 received in 5 years—at a lottery for example—be worth today?).
It follows that if one has to choose between receiving $100 today and $100 in one year, the rational decision is to choose the $100 today. If the money is to be received in one year and assuming the savings account interest rate is 5%, the person has to be offered at least $105 in one year so that the two options are equivalent (either receiving $100 today or receiving $105 in one year). This is because if $100 is deposited in a savings account, the value will be $105 after one year, again assuming no risk of losing the initial amount through bank default.
Interest rates
Interest is the additional amount of money gained between the beginning and the end of a time period. Interest represents the time value of money, and can be thought of as rent that is required of a borrower in order to use money from a lender.^{[2]}^{[4]} For example, when an individual takes out a bank loan, the individual is charged interest. Alternatively, when an individual deposits money into a bank, the money earns interest. In this case, the bank is the borrower of the funds and is responsible for crediting interest to the account holder. Similarly, when an individual invests in a company (through corporate bonds, or through stock), the company is borrowing funds, and must pay interest to the individual (in the form of coupon payments, dividends, or stock price appreciation).^{[1]} The interest rate is the change, expressed as a percentage, in the amount of money during one compounding period. A compounding period is the length of time that must transpire before interest is credited, or added to the total.^{[2]} For example, interest that is compounded annually is credited once a year, and the compounding period is one year. Interest that is compounded quarterly is credited four times a year, and the compounding period is three months. A compounding period can be any length of time, but some common periods are annually, semiannually, quarterly, monthly, daily, and even continuously.
There are several types and terms associated with interest rates:
 Compound interest, interest that increases exponentially over subsequent periods,
 Simple interest, additive interest that does not increase
 Effective interest rate, the effective equivalent compared to multiple compound interest periods
 Nominal annual interest, the simple annual interest rate of multiple interest periods
 Discount rate, an inverse interest rate when performing calculations in reverse
 Continuously compounded interest, the mathematical limit of an interest rate with a period of zero time.
 Real interest rate, which accounts for inflation.
Calculation
The operation of evaluating a present sum of money some time in the future is called a capitalization (how much will 100 today be worth in five years?). The reverse operation—evaluating the present value of a future amount of money—is called discounting (how much will 100 received in five years be worth today?).^{[4]}
Spreadsheets commonly offer functions to compute present value. In Microsoft Excel, there are present value functions for single payments  "=NPV(...)", and series of equal, periodic payments  "=PV(...)". Programs will calculate present value flexibly for any cash flow and interest rate, or for a schedule of different interest rates at different times.
Present value of a lump sum
The most commonly applied model of present valuation uses compound interest. The standard formula is:
Where is the future amount of money that must be discounted, is the number of compounding periods between the present date and the date where the sum is worth , is the interest rate for one compounding period (the end of a compounding period is when interest is applied, for example, annually, semiannually, quarterly, monthly, daily). The interest rate, , is given as a percentage, but expressed as a decimal in this formula.
Often, is referred to as the Present Value Factor ^{[2]}
This is also found from the formula for the future value with negative time.
For example, if you are to receive $1000 in five years, and the effective annual interest rate during this period is 10% (or 0.10), then the present value of this amount is
The interpretation is that for an effective annual interest rate of 10%, an individual would be indifferent to receiving $1000 in five years, or $620.92 today.^{[1]}
The purchasing power in today's money of an amount of money, years into the future, can be computed with the same formula, where in this case is an assumed future inflation rate.
Net present value of a stream of cash flows
A cash flow is an amount of money that is either paid out or received, differentiated by a negative or positive sign, at the end of a period. Conventionally, cash flows that are received are denoted with a positive sign (total cash has increased) and cash flows that are paid out are denoted with a negative sign (total cash has decreased). The cash flow for a period represents the net change in money of that period.^{[4]} Calculating the net present value, , of a stream of cash flows consists of discounting each cash flow to the present, using the present value factor and the appropriate number of compounding periods, and combining these values.^{[1]}
For example, if a stream of cash flows consists of +$100 at the end of period one, $50 at the end of period two, and +$35 at the end of period three, and the interest rate per compounding period is 5% (0.05) then the present value of these three Cash Flows are:
 respectively
Thus the net present value would be:
There are a few considerations to be made.
 The periods might not be consecutive. If this is the case, the exponents will change to reflect the appropriate number of periods
 The interest rates per period might not be the same. The cash flow must be discounted using the interest rate for the appropriate period: if the interest rate changes, the sum must be discounted to the period where the change occurs using the second interest rate, then discounted back to the present using the first interest rate.^{[2]} For example, if the cash flow for period one is $100, and $200 for period two, and the interest rate for the first period is 5%, and 10% for the second, then the net present value would be:
 The interest rate must necessarily coincide with the payment period. If not, either the payment period or the interest rate must be modified. For example, if the interest rate given is the effective annual interest rate, but cash flows are received (and/or paid) quarterly, the interest rate per quarter must be computed. This can be done by converting effective annual interest rate, , to nominal annual interest rate compounded quarterly:
 ^{[2]}
Here, is the nominal annual interest rate, compounded quarterly, and the interest rate per quarter is
Present value of an annuity
Many financial arrangements (including bonds, other loans, leases, salaries, membership dues, annuities including annuityimmediate and annuitydue, straightline depreciation charges) stipulate structured payment schedules; payments of the same amount at regular time intervals. Such an arrangement is called an annuity. The expressions for the present value of such payments are summations of geometric series.
There are two types of annuities: an annuityimmediate and annuitydue. For an annuity immediate, payments are received (or paid) at the end of each period, at times 1 through , while for an annuity due, payments are received (or paid) at the beginning of each period, at times 0 through .^{[4]} This subtle difference must be accounted for when calculating the present value.
An annuity due is an annuity immediate with one more interestearning period. Thus, the two present values differ by a factor of :
 ^{[2]}
The present value of an annuity immediate is the value at time 0 of the stream of cash flows:
where:
 = number of periods,
 = amount of cash flows,
 = effective periodic interest rate or rate of return.
An approximation for annuity and loan calculations
The above formula (1) for annuity immediate calculations offers little insight for the average user and requires the use of some form of computing machinery. There is an approximation which is less intimidating, easier to compute and offers some insight for the nonspecialist. It is given by ^{[5]}
Where, as above, C is annuity payment, PV is principal, n is number of payments, starting at end of first period, and i is interest rate per period. Equivalently C is the periodic loan repayment for a loan of PV extending over n periods at interest rate, i. The formula is valid (for positive n, i) for ni≤3. For completeness, for ni≥3 the approximation is .
The formula can, under some circumstances, reduce the calculation to one of mental arithmetic alone. For example, what are the (approximate) loan repayments for a loan of PV = $10,000 repaid annually for n = ten years at 15% interest (i = 0.15)? The applicable approximate formula is C ≈ 10,000*(1/10 + (2/3) 0.15) = 10,000*(0.1+0.1) = 10,000*0.2 = $2000 pa by mental arithmetic alone. The true answer is $1993, very close.
The overall approximation is accurate to within ±6% (for all n≥1) for interest rates 0≤i≤0.20 and within ±10% for interest rates 0.20≤i≤0.40. It is, however, intended only for "rough" calculations.
Present value of a perpetuity
A perpetuity refers to periodic payments, receivable indefinitely, although few such instruments exist. The present value of a perpetuity can be calculated by taking the limit of the above formula as n approaches infinity.
Formula (2) can also be found by subtracting from (1) the present value of a perpetuity delayed n periods, or directly by summing the present value of the payments
which form a geometric series.
Again there is a distinction between a perpetuity immediate – when payments received at the end of the period – and a perpetuity due – payment received at the beginning of a period. And similarly to annuity calculations, a perpetuity due and a perpetuity immediate differ by a factor of :
 ^{[2]}
PV of a bond
A corporation issues a bond, an interest earning debt security, to an investor to raise funds.^{[4]} The bond has a face value, , coupon rate, , and maturity date which in turn yields the number of periods until the debt matures and must be repaid. A bondholder will receive coupon payments semiannually (unless otherwise specified) in the amount of , until the bond matures, at which point the bondholder will receive the final coupon payment and the face value of a bond, . The present value of a bond is the purchase price.^{[2]} The purchase price is equal to the bond's face value if the coupon rate is equal to the current interest rate of the market, and in this case, the bond is said to be sold 'at par'. If the coupon rate is less than the market interest rate, the purchase price will be less than the bond's face value, and the bond is said to have been sold 'at a discount', or below par. Finally, if the coupon rate is greater than the market interest rate, the purchase price will be greater than the bond's face value, and the bond is said to have been sold 'at a premium', or above par.^{[4]} The purchase price can be computed as:
Technical details
Present value is additive. The present value of a bundle of cash flows is the sum of each one's present value.
In fact, the present value of a cashflow at a constant interest rate is mathematically one point in the Laplace transform of that cashflow, evaluated with the transform variable (usually denoted "s") equal to the interest rate. The full Laplace transform is the curve of all present values, plotted as a function of interest rate. For discrete time, where payments are separated by large time periods, the transform reduces to a sum, but when payments are ongoing on an almost continual basis, the mathematics of continuous functions can be used as an approximation.
These calculations must be applied carefully, as there are underlying assumptions:
 That it is not necessary to account for price inflation, or alternatively, that the cost of inflation is incorporated into the interest rate.
 That the likelihood of receiving the payments is high—or, alternatively, that the default risk is incorporated into the interest rate.
See time value of money for further discussion.
Variants/approaches
There are mainly two flavors of Present Value. Whenever there will be uncertainties in both timing and amount of the cash flows, the expected present value approach will often be the appropriate technique.
 Traditional Present Value Approach – in this approach a single set of estimated cash flows and a single interest rate (commensurate with the risk, typically a weighted average of cost components) will be used to estimate the fair value.
 Expected Present Value Approach – in this approach multiple cash flows scenarios with different/expected probabilities and a creditadjusted risk free rate are used to estimate the fair value.
Choice of interest rate
The interest rate used is the riskfree interest rate if there are no risks involved in the project. The rate of return from the project must equal or exceed this rate of return or it would be better to invest the capital in these risk free assets. If there are risks involved in an investment this can be reflected through the use of a risk premium. The risk premium required can be found by comparing the project with the rate of return required from other projects with similar risks. Thus it is possible for investors to take account of any uncertainty involved in various investments.
Present value method of valuation
An investor, the lender of money, must decide the financial project in which to invest their money, and present value offers one method of deciding.^{[1]} A financial project requires an initial outlay of money, such as the price of stock or the price of a corporate bond. The project claims to return the initial outlay, as well as some surplus (for example, interest, or future cash flows). An investor can decide which project to invest in by calculating each projects’ present value (using the same interest rate for each calculation) and then comparing them. The project with the smallest present value – the least initial outlay – will be chosen because it offers the same return as the other projects for the least amount of money.^{[2]}
See also
References
 ^ ^{a} ^{b} ^{c} ^{d} ^{e} ^{f} Moyer, Charles; William Kretlow; James McGuigan (2011). Contemporary Financial Management (12 ed.). Winsted: SouthWestern Publishing Co. pp. 147–498. ISBN 9780538479172.
 ^ ^{a} ^{b} ^{c} ^{d} ^{e} ^{f} ^{g} ^{h} ^{i} ^{j} Broverman, Samuel (2010). Mathematics of Investment and Credit. Winsted: ACTEX Publishers. pp. 4–229. ISBN 9781566987677.
 ^ Youings, Joyce, "Devon Monastic Lands: Calendar of Particulars for Grants 1536–1558", Devon & Cornwall Record Society, New Series, Vol.1, 1955
 ^ ^{a} ^{b} ^{c} ^{d} ^{e} ^{f} Ross, Stephen; Randolph W. Westerfield; Bradford D. Jordan (2010). Fundamentals of Corporate Finance (9 ed.). New York: McGrawHill. pp. 145–287. ISBN 9780077246129.
 ^ Swingler, D. N., (2014), "A Rule of Thumb approximation for time value of money calculations", Journal of Personal Finance, Vol. 13,Issue 2, pp.5761
Further reading
 Henderson, David R. (2008). "Present Value". Concise Encyclopedia of Economics (2nd ed.). Indianapolis: Library of Economics and Liberty. ISBN 9780865976658. OCLC 237794267.