How to use this calculator
- Enter or choose starting amount.
- Enter or choose payment per period.
- Enter or choose interest rate (per year).
- Enter or choose years.
- Enter or choose periods per year.
- The future value updates as you type. Use Copy result or Share to keep it.
Method
FV = PV × (1 + i)ⁿ + PMT × ((1 + i)ⁿ − 1) ÷ i × (1 + i if paid at the start)
- i
- annual rate ÷ periods per year
- n
- years × periods per year
- PMT
- payment each period
Worked example
- i = 6% ÷ 12 = 0.5% and n = 120; (1.005)¹²⁰ = 1.819397.
- Lump sum: 1,000 × 1.819397 = $1,819.40.
- Payments: 100 × (1.819397 − 1) ÷ 0.005 = $16,387.93; total $18,207.33.
$1,000 plus $100 a month at 6% grows to $18,207.33 in 10 years, of which $5,207.33 is interest.
What the result means
The gap between the two chart lines is interest. It widens over time because earlier interest earns interest of its own.
Assumptions and limits
- A constant rate, compounded once per payment period.
- Equal payments at regular intervals.
- Tax, fees and inflation are not deducted; use the Inflation Calculator to see the result in today’s money.
Questions
How is this different from the compound interest calculator?
It uses one period length for both compounding and payments and lets you choose payments at the start or end of each period, the standard time-value-of-money set-up used in finance courses and spreadsheets.
What is an annuity due?
A series of payments made at the start of each period. Each payment earns one extra period of interest, so the future value is (1 + i) times higher.
Please note: Returns are illustrations at a constant rate, not predictions or guarantees. Investments can lose value. This is not investment advice.