The Future Value of an Annuity Calculator projects the balance built by a series of equal periodic payments earning a fixed interest rate, the exact math behind a regular savings plan, a retirement contribution schedule, or any recurring deposit strategy. Enter the payment amount, the annual rate, the number of years and how often payments are made, and the calculator returns the accumulated future value.
Unlike a single lump-sum deposit, an annuity in this sense means a repeated series of equal payments made at regular intervals. Each payment compounds for a different length of time, since earlier payments have longer to grow than later ones, and the future value formula accounts for that automatically across every payment in the series.
*These results are estimates for information only, not investment advice.*
Understand the future value annuity formula
The formula is Future Value = Payment x [((1 + i)^n - 1) / i], where i is the interest rate per period and n is the total number of payments.
This single equation sums the compounded value of every individual payment in the series, from the first payment (which compounds for nearly the entire term) to the last payment (which has barely any time to grow before the term ends).
Take a $200 payment made every month for 10 years at a 5% annual rate, compounded monthly, so the monthly rate is 5% divided by 12 and the number of payments is 10 x 12 = 120. Running those numbers through the formula produces a future value of approximately $31,056.46. Since total contributions over the period are $200 x 120, or $24,000, the remaining $7,056.46 represents interest earned purely from compounding across the series of payments.
See how payment size and frequency shape the outcome
The future value scales linearly with payment size: doubling the monthly payment exactly doubles the resulting future value at the same rate, term and frequency.
Payment frequency, however, changes both the periodic rate and the total number of payments used in the formula, and more frequent payments of an equivalent total annual amount generally produce a slightly larger future value, since money begins compounding sooner within each year.
The Future Value of an Annuity Calculator lets each of these variables be tested independently, so the effect of raising a monthly contribution, extending the savings term, or switching from quarterly to monthly deposits can be seen directly in the resulting balance.
Compare a savings plan to a single lump-sum deposit
A $200 monthly payment over 10 years at 5% builds to about $31,056.46, considerably more than the $16,470.09 a single $10,000 lump sum would grow to over the same period and rate, even though the total money committed differs in each case ($24,000 in contributions for the annuity versus $10,000 upfront for the lump sum).
This comparison illustrates why regular contributions, even without a large starting balance, can build meaningful wealth over time when combined with a reasonable rate and a long enough horizon.
Someone deciding between saving a smaller amount regularly versus a single larger deposit can use both this calculator and a lump-sum future value calculator side by side to compare the two strategies directly under the same rate and term assumptions.
Understand the ordinary annuity assumption
This calculation assumes an ordinary annuity, meaning each payment occurs at the end of its period rather than the beginning. An annuity due, where payments occur at the start of each period instead, would produce a very slightly larger future value, since each payment would then have one extra period to compound before the end of the term.
Most standard savings plans, loan payments and typical recurring deposit schedules follow the ordinary annuity convention this calculator uses.
Know what this projection assumes
This calculation assumes every payment is made exactly on schedule for the entire term, at a fixed interest rate that never changes, with no fees or taxes deducted from the growing balance. Real savings plans may see missed contributions, rate changes, or account fees that would cause an actual balance to differ from this idealized projection.
Use the Future Value of an Annuity Calculator to understand how consistent contributions compound over time and to set a realistic savings target. Revisit the projection periodically with updated rate and contribution assumptions as an actual plan unfolds.
Frequently asked questions
What is the formula for the future value of an annuity?
The formula is Future Value = Payment x [((1 + i)^n - 1) / i], where i is the interest rate per period and n is the total number of payments. It sums the compounded value of every payment in the series across the term.
How much does saving $200 a month for 10 years at 5% grow to?
Saving $200 a month for 10 years at a 5% annual rate compounded monthly grows to approximately $31,056.46, with $24,000 of that total coming from contributions and about $7,056.46 from compounded interest.
Why is the future value of a monthly savings plan larger than a similar lump sum?
A savings plan often produces a larger future value than a comparably sized single deposit because it adds new money to the balance continuously over the term, letting more total dollars benefit from compounding, even though no single contribution is as large as a lump sum would be.
What is an ordinary annuity?
An ordinary annuity assumes each payment occurs at the end of its period rather than the beginning. This calculator uses that standard convention, matching how most savings plans and recurring deposits are actually structured.
Does increasing the payment frequency always increase the future value?
Generally yes, for the same total annual contribution amount, making payments more frequently (such as monthly instead of quarterly) tends to produce a slightly larger future value, since money begins compounding sooner within each year.
Summary
The Future Value of an Annuity Calculator projects the balance built by regular equal payments using Future Value = Payment x [((1 + i)^n - 1) / i]. Saving $200 a month for 10 years at a 5% annual rate builds to approximately $31,056.46, with $24,000 from contributions and $7,056.46 from compounding.
This is the mechanic behind regular savings plans and recurring retirement contributions, distinct from a single lump-sum projection. Figures shown are estimates for planning only, not investment advice.