Annuity Calculator

How it works

Accumulating a stream of contributions

An annuity accumulation calculation models a sequence of contributions growing over time. Earlier contributions usually remain invested for more periods than later ones, so timing matters. Compare the total contributed with the ending balance and keep the payment schedule aligned with the selected mode. Contract charges, changing returns, or withdrawals need explicit treatment before this becomes a model of a particular annuity product.

Accumulate an annuity: formula and assumptions

FV = PV(1+i)^n + PMT[(1+i)^n−1]/i.

Annuity here means a stream of equal cash flows. Insurance product fees, guarantees, and mortality pricing are excluded.

Monthly + annual contributions: formula and assumptions

Ending balance = opening growth + each contribution grown from its event time − modeled interest tax.

The annual stream is additional to twelve monthly contributions. Increases apply separately to each stream. Tax settles at year ends and the final partial year; inflation adjusts purchasing power.

Worked example

Reference example currency: USD. These fixed examples do not change with your calculator preferences.

Using the Accumulate an annuity example:

Starting balance ($)

10000

Periodic contribution ($)

500

Annual effective return (%)

5

Years

20

Contributions per year

Monthly

Payment timing

End

FV = PV(1+i)^n + PMT[(1+i)^n−1]/i.

Example result

These are illustrative inputs. Change the values to explore a different scenario.

Formula references

• Investor.gov: financial tools (opens in a new tab)

References explain the underlying methods; they do not imply endorsement or individual professional review of Finflo.

Common questions