Tool 8

Investment calculators · Matched periodic assumptions

Future Value Calculator

Created by Arunangshu DasReviewed Nov 4, 2026

Model a lump sum and equal deposits with an explicit rate per period. Inspect the payment timeline, contributed capital and modeled growth.

An equal-period savings scenario before fees, taxes and inflation. No forecast or personalized financial advice.

Preparing calculator…

Match all three period units

Monthly rate → monthly deposit → count months. No annual-rate conversion or calendar unit is inferred.

Display market and currency

Formatting only; no currency conversion or tax rules.

Starting amount (USD)

Money at period 0. Nonnegative, at most 10^15; explicit zero is allowed.

Deposit per period (USD)

Equal nonnegative payment each period, at most 10^15. Enter 0 for a lump sum; blank is not zero.

Rate per period (%)

Greater than −100% through 1000%. Not an annual quote unless your period is one year. Use an ordinary minus sign for negative rates.

Number of complete periods

Whole count 0–36500. For 18 months with monthly rate and deposits, enter 18. No fractional periods, dates or leap-day counting.

Deposit timing

Both timings include exactly N deposits when N is positive and the payment is nonzero. Zero periods includes none.

Future value

Enter all four numeric assumptions or load the verified 18-period example.

80 significant decimal digits internally; half-even currency display at 2 places. Tiny nonzero amounts are marked. Inputs stay in browser memory. No per-period cent rounding, withdrawals, varying rates or inverse solving.

Keep rate, deposits and count in the same period

For a monthly rate, enter a monthly deposit and count months. Eighteen monthly periods means 18, not 1.5. No annual-rate conversion is inferred.

Read the complete future value guide

Formula and methodology

q = 1 + R/100; FV = Pq^N + CΣ(q^k), k=0…N−1
Beginning timing multiplies only the deposit term by q.
At zero rate: FV=P+CN. At zero periods: FV=P, no recurring deposit.

Set i=R/100 and q=1+i. Grown starting money is Pq^N. End-period deposits contribute C×sum(q^k, k=0…N−1); beginning deposits multiply only that sum by q. Future value is the sum of those two grown components. Actual contributions are P+CN, and interest is future value minus actual contributions. At zero rate use P+CN; at zero periods use P with no recurring deposit.

Verified worked examples

Start with 1,000, deposit 100 at each month-end, use 1% per month and count 18 months. Grown starting money is 1,196.1474756867; grown deposits are 1,961.4747568666. Future value is 3,157.6222325533 (3,157.62 displayed), actual contributions are 2,800 and interest is 357.6222325533. Moving the same 18 deposits to period starts gives 3,177.2369801220 (3,177.24 displayed). These are hypothetical assumptions, not expected returns.

Inputs and interpretation

Choose a display market. Enter starting amount and deposit (explicit 0 for a lump sum), then rate per period and complete period count. Choose beginning or end timing. Check that all three period units match, inspect the deposit timeline, and read contributed capital separately from interest. Use Clear values to remove the in-memory scenario.

Assumptions and limitations

The supplied rate and deposit apply to exactly the same equal period. A monthly rate needs a monthly deposit and a count of months. Growth is constant and reinvested; payments are level and timing is explicit. No calendar dates, leap-day accrual or day-count adjustments are inferred. No per-period cent rounding is imposed.

Supported domain and common mistakes

P and C each range from 0 through 10^15. R must be greater than −100% and at most 1000% per period; N is a whole count from 0 through 36500. Inputs use ungrouped decimal points, at most 12 fractional places and 48 characters. Ending values above 10^30 are rejected. No withdrawals, changing rates, fractional payment counts, annual-rate conversion, inverse solve, taxes, fees, inflation or FX are included.

Do not enter an annual effective yield as a monthly rate or divide it by 12 without deriving the correct convention. Eighteen monthly periods are 18, not 1.5 periods. Beginning timing moves the same N deposits earlier; it does not add an extra payment. Positive deposits here correspond to negative PV/PMT outflows in the Excel FV convention.

Frequently asked questions

What does rate per period mean?

It is the growth percentage for one supplied equal period. If you enter a monthly rate, enter a monthly deposit and count months. There is no automatic conversion from annual nominal or effective quotes.

Can I calculate the future value of a lump sum?

Yes. Enter the starting amount, enter an explicit 0 deposit, and supply the rate and whole period count. Deposit timing then has no effect. Blank deposits are not silently treated as zero.

How many deposits occur at the beginning?

For N positive periods and a nonzero payment, beginning timing uses exactly N deposits at indices 0 through N−1. End timing uses 1 through N. At zero periods neither option adds a recurring deposit.

Can the rate be zero or negative?

Yes. Zero gives starting amount plus deposit times count. Negative rates greater than −100% reduce each existing balance per period; contributions can still increase the ending amount. Rates of −100% or below are outside this model.

Does 18 periods mean 18 months?

Only if your rate and deposit are monthly. Periods have no hidden calendar unit. The calculator accepts a complete integer count and does not infer dates, leap years or fractional payment counts.

Why does Excel FV sometimes show a negative answer?

Excel uses cash-flow signs. To compare with positive savings P and C here, use FV(R/100,N,-C,-P,type), where type is 0 for end or 1 for beginning. Match the rate period and assumptions; this is not a full Excel compatibility guarantee.

Does choosing INR, USD or another currency convert my result?

No. USD, GBP, CAD, AUD and INR affect formatting only. Inputs stay numerically unchanged and there is no exchange-rate, tax or inflation model.

Sources and educational scope

Educational scenario arithmetic, not personalized investment advice, a product quotation or a guaranteed forecast. Real cash flows, fees, tax, inflation, risk and agreement-specific posting rules can materially change outcomes. Verify the assumptions before using a result for a decision.

Reviewed 2026-11-04. AI-assisted content under operator editorial responsibility; no independent expert financial review is claimed.