Annuity Calculator
Value a stream of equal payments, or find the payment a lump sum can sustain.
What the Annuity Calculator does
An annuity is a series of equal payments. This calculator works both directions: what a lump sum can pay out over a fixed period, and what a stream of payments is worth today. Money left in the pot keeps earning, which is why total payouts exceed the starting sum.
Formula
PV = PMT × (1 − (1 + r)⁻ⁿ) ÷ rPMT = PV × r ÷ (1 − (1 + r)⁻ⁿ)Annuity due adjusts by a factor of (1 + r)
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| What do you want to find? | one of 2 options | Yes | — |
| Lump sum available | selected currency | In some modes | Accepts more than 0. Shown What do you want to find? is Payment a lump sum can provide. |
| Payment per period | selected currency | In some modes | Accepts more than 0. Shown What do you want to find? is Value of a payment stream. |
| Annual interest rate | % | Yes | — |
| Number of years | years | Yes | Accepts more than 0, up to 100. |
| Payment frequency | one of 3 options | Yes | — |
| Payments occur | one of 2 options | Yes | — |
| Currency | one of 10 options | Optional | — |
How to use it
- Choose What do you want to find? and Payment frequency.
- Enter Annual interest rate and Number of years.
- Fill in the remaining inputs the form shows for your choice.
- Select Calculate.
Worked example
$500,000 paying out monthly over 25 years at 5%.
- Mode
- Payment
- Lump sum
- 500000
- Rate
- 5
- Years
- 25
$2,922.95 a month, totalling $876,885 across the term.
Frequently asked questions
Does this account for inflation?
No — payments stay flat in nominal terms. Their purchasing power falls over time, so use a real (inflation-adjusted) rate if you want constant buying power.