Present and Future Value Examples in Math

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Present and Future Value.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Math.

Concept Recap

The concept that money has different values at different points in time. Future value (FVFV) calculates what a present amount will grow to; present value (PVPV) calculates what a future amount is worth today, using discounting.

Would you rather have \$100 today or \$100 in five years? Today, obviouslyβ€”because you could invest the \$100 and have MORE than \$100 in five years. Present value answers: 'How much would I need TODAY to have \$X in the future?' Future value answers: 'If I invest \$X today, what will it become?' Discounting is the reverse of compoundingβ€”it shrinks future money back to today's value.

Read the full concept explanation β†’

How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Future value compounds a present amount forward; present value discounts a future amount back to today.

Common stuck point: The procedure for present and future value is the easy part; the trap is discounting when you meant to grow (or vice versa). Asking "Am I moving one sum of money forward (growing) or backward (discounting) along the timeline?" first is what keeps a correct-looking calculation from being attached to the wrong concept.

Sense of Study hint: Ask: Am I moving one sum of money forward (growing) or backward (discounting) along the timeline?

Worked Examples

Example 1

easy
Find the future value of $5,000\$5{,}000 invested at 4%4\% annual interest compounded annually for 66 years.

Answer

$6,326.60\$6{,}326.60

First step

1
The future value formula for compound interest is FV=PVβ‹…(1+r)nFV = PV \cdot (1 + r)^n.

Full solution

  1. 2
    Substitute: FV=5000(1.04)6FV = 5000(1.04)^6.
  2. 3
    (1.04)6β‰ˆ1.2653(1.04)^6 \approx 1.2653, so FVβ‰ˆ5000Γ—1.2653=$6,326.60FV \approx 5000 \times 1.2653 = \$6{,}326.60.
Future value tells you how much a present sum will be worth after earning compound interest. The formula FV=PV(1+r)nFV = PV(1+r)^n assumes interest is reinvested (compounded). The interest earned is $1,326.60\$1{,}326.60 β€” more than simple interest ($1,200\$1{,}200) because of compounding.

Example 2

medium
How much should you invest today at 5%5\% annual interest compounded quarterly to have $20,000\$20{,}000 in 88 years?

Example 3

medium
How much should you invest today at 6% annual compounding to have $5000 in 4 years? Use 1.064=1.262476961.06^4 = 1.26247696.

Example 4

medium
Find the FV of $3000 at 8% annual compounding for 5 years. Use 1.085β‰ˆ1.469331.08^5 \approx 1.46933.

Example 5

medium
Compute NPV: invest \$1000 today, receive \$600 at year 1 and \$600 at year 2, discount rate 10%.

Example 6

hard
Compute NPV of a project: -$2000 today, +$800 each year for 3 years, r=8%r=8\%. Use 1.08,1.1664,1.2597121.08, 1.1664, 1.259712.

Example 7

hard
You invest $1000 at 5% annual compounding. After how many whole years does the balance first exceed $1500? Use ln⁑1.5β‰ˆ0.4055\ln 1.5 \approx 0.4055, ln⁑1.05β‰ˆ0.04879\ln 1.05 \approx 0.04879.

Example 8

challenge
At an annual rate of 8% compounded annually, what equal annual deposit at the end of each year for 5 years grows to $10000? Use FV-of-annuity factor ((1.08)5βˆ’1)/0.08β‰ˆ5.8666((1.08)^5-1)/0.08 \approx 5.8666.

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

medium
An investment doubles in 99 years with annual compounding. What is the approximate annual interest rate?

Example 2

hard
Compare the future values of $10,000\$10{,}000 invested for 2020 years at 6%6\% with (a) annual compounding, (b) monthly compounding, and (c) continuous compounding.

Example 3

easy
Find the future value of 100100 invested for 1 year at 10% annual interest.

Example 4

easy
Find the present value of 110110 received in 1 year at 10% discount rate.

Example 5

easy
What is the future value of 200200 in 2 years at 5% annual interest?

Example 6

easy
Find the present value of 121121 in 2 years at 10%.

Example 7

easy
Would you rather have 100todayor100 today or 100 in 5 years? Why (one reason)?

Example 8

easy
At a 0% interest rate, what is the present value of 500500 received in 3 years?

Example 9

easy
Find the future value of 10001000 in 1 year at 8%.

Example 10

easy
A project's NPV is positive. Does it earn more or less than the discount rate?

Example 11

medium
Find the future value of 500500 in 3 years at 6% compounded annually.

Example 12

medium
Find the present value of 10001000 received in 4 years at 5%.

Example 13

medium
Money doubles under 7% annual compounding in about how many years? (Use (1.07)10β‰ˆ1.967(1.07)^{10}\approx1.967.)

Example 14

medium
Compare: 10001000 now vs 12001200 in 3 years at 5%. Which is worth more today?

Example 15

medium
Find the future value of 20002000 at 6% compounded semiannually for 2 years.

Example 16

medium
What annual rate doubles 100100 to 200200 in exactly 8 years if (1+r)8=2(1+r)^8=2 and 21/8β‰ˆ1.09052^{1/8}\approx1.0905?

Example 17

medium
Find the present value of 300300 in 1 year plus 300300 in 2 years at 10%.

Example 18

medium
An investment costs 900900 today and returns 10001000 in 1 year. At 5%, find its NPV.

Example 19

medium
Find the present value of 500500 received in 2 years at 8%.

Example 20

challenge
How long until 10001000 grows to 15001500 at 6% annual compounding? Use log⁑\log and round to two decimals. (ln⁑1.5β‰ˆ0.405465\ln1.5\approx0.405465, ln⁑1.06β‰ˆ0.058269\ln1.06\approx0.058269.)

Example 21

challenge
A bond pays 5050 at year 1, 5050 at year 2, and 10501050 at year 3. At 5%, find its price (present value).

Example 22

challenge
You can invest 50005000 today at 7% or receive 70007000 in 5 years. Which is better? (1.075β‰ˆ1.4025521.07^5\approx1.402552.)

Example 23

easy
Find the future value of \$1000 invested for 2 years at 10% annual interest, compounded annually.

Example 24

easy
Find the present value of \$200 received in 2 years at a 0% discount rate.

Example 25

easy
Find the future value of \$500 in 1 year at 4% annual interest.

Example 26

easy
Find the present value of \$400 received in 1 year at 25%.

Example 27

easy
Find the future value of $1000 invested for 3 years at 5% annual compounding. Use 1.053=1.1576251.05^3 = 1.157625.

Example 28

medium
Find the future value of $2000 in 4 years at 5% compounded quarterly. Use (1.0125)16β‰ˆ1.21989(1.0125)^{16} \approx 1.21989.

Example 29

medium
Find the present value of $10000 received in 10 years at 6% annual compounding. Use 1.0610β‰ˆ1.790851.06^{10} \approx 1.79085.

Example 30

medium
Using the Rule of 72, estimate how long it takes for money to double at 6% annual compounding.

Example 31

medium
You will receive $1000 in 5 years. Should you accept $700 today if the discount rate is 8%? Use 1.085β‰ˆ1.469331.08^5 \approx 1.46933, so PVβ‰ˆ680.58PV \approx 680.58.

Example 32

medium
Find the present value of $200 in 1 year plus $200 in 2 years at 8%. Use 1.082=1.16641.08^2 = 1.1664.

Example 33

medium
Find the FV of $5000 at 4% compounded semiannually for 3 years. Use (1.02)6β‰ˆ1.12616(1.02)^6 \approx 1.12616.

Example 34

hard
What annual rate doubles money in 5 years? Use 21/5β‰ˆ1.148702^{1/5} \approx 1.14870.

Example 35

hard
Find the present value of $100 received in 30 years at 5%. Use 1.0530β‰ˆ4.321941.05^{30} \approx 4.32194.

Example 36

hard
A bond pays $50 yearly for 5 years and $1000 at year 5. At 6%, find its price. Use 1.065β‰ˆ1.338231.06^5 \approx 1.33823, and annuity factor βˆ‘t=151.06βˆ’tβ‰ˆ4.21236\sum_{t=1}^5 1.06^{-t}\approx 4.21236.

Example 37

hard
You owe $10000 in 3 years. How much should you set aside today at 7% compound interest? Use 1.073β‰ˆ1.225041.07^3 \approx 1.22504.

Example 38

challenge
Compare continuous compounding to annual compounding. Find FV of $1000 at 5% for 10 years under each. Use e0.5β‰ˆ1.64872e^{0.5}\approx 1.64872 and 1.0510β‰ˆ1.628891.05^{10}\approx 1.62889.

Background Knowledge

These ideas may be useful before you work through the harder examples.

compound interest