Future value measures the accumulated value of equal periodic payments, with results determined by rate, term, and payment timing.
The future value of an annuity is the accumulated value, at a specified future date, of equal payments made at regular intervals. It combines the payments themselves with the compound growth each earlier payment earns before the valuation date.
Despite the name, this calculation is not limited to insurance annuity contracts. It can model any level-payment cash-flow stream, including regular savings deposits, a sinking fund, or scheduled contributions to an account.
For an ordinary annuity, in which each payment occurs at the end of a period:
Where:
The expression in parentheses is the future value annuity factor. Multiplying the factor by the periodic payment converts the level stream into one ending value.
For an annuity due, each payment is made one period earlier, so each payment compounds for one additional period:
If (r=0), do not divide by zero. With no growth, the future value is simply:
Suppose five equal deposits are made at the end of five annual periods. At the end of year five:
The annuity formula is a shortcut for adding those separately compounded deposits. This timing logic is why the time value of money matters even when every payment has the same dollar amount.
Assume a saver deposits $500 at the end of every month for five years. For illustration, the account earns a constant 0.5% per month and has no fees or taxes.
The inputs are:
The saver contributes $30,000 in total. Under these assumptions, approximately $4,885.02 of the ending value comes from compounded growth.
If the same deposits occur at the beginning of each month, the stream is an annuity due:
The annuity-due result is higher because every deposit receives one additional month of compounding. The assumed return is only an input to the example; actual returns, credited rates, fees, and taxes can produce a different balance.
| Feature | Ordinary annuity | Annuity due |
|---|---|---|
| Payment date | End of each period | Beginning of each period |
| First payment | One period after the valuation date | At the valuation date |
| Compounding time | Standard | One extra period per payment |
| FV relationship | Base value | Ordinary-annuity FV multiplied by (1+r) |
| Typical example | End-of-month savings deposit | Beginning-of-month deposit |
Use the cash-flow dates in the agreement or account record rather than relying on a label. A real stream may not be a perfect annuity if payment amounts or intervals change.
Before accepting the output, check each input:
Using 6% as (r) in a monthly model would apply 6% every month, not 6% per year. The correct periodic rate depends on how the quoted annual rate is defined and compounded.
Present value of an annuity discounts payments to an earlier date. Future value compounds them to a later date.
The formula assumes the selected rate applies consistently. Market-linked returns can vary, and even contractual rates may be subject to terms, crediting methods, expenses, or issuer risk.
Future value is usually stated in nominal dollars. A larger future balance does not by itself show how much purchasing power that balance will have.
Future-value annuity calculations can help compare regular saving schedules, estimate a sinking fund, or reconcile a spreadsheet model. They are less reliable when returns vary materially, cash flows are irregular, fees are not modeled, or the goal requires inflation-adjusted purchasing power.
An insurance annuity is a contract with product-specific costs, risks, benefits, and payment terms. The U.S. Securities and Exchange Commission’s Investor.gov annuity guide explains that contract features differ and that insurer obligations depend on the insurer’s financial strength. A textbook annuity calculation does not evaluate those product risks or establish that a contract is suitable.
This article explains valuation mechanics for educational purposes. It does not provide a return forecast or personalized investment, tax, insurance, or retirement advice.