Annuity Calculator
$0.00 ending balance
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How This Annuity Calculator Works
This calculator projects the future value of an annuity: a starting balance plus a series of equal, regularly timed deposits, all growing at a compounded interest rate. Interest is compounded using the frequency you select, and deposits are converted to that same compounding period internally so the math stays consistent even if you deposit monthly but compounding is set to daily or annually. By default, deposits are assumed to land at the end of each period (an "ordinary annuity," the most common setup for retirement and savings contributions) — switch to "start of period" if your deposits post at the beginning of each period, such as some lease or insurance payment structures, since that gives each contribution one extra period to earn interest.
Why the Deposit Timing Toggle Matters
The difference between an ordinary annuity and an annuity due seems small but compounds meaningfully over decades. Moving deposits to the start of each period means every single contribution earns one additional period of interest, which can add up to thousands of dollars over a long horizon at higher rates. If you're unsure which applies to you, most payroll-deducted retirement contributions (like a 401(k)) and manual monthly transfers are ordinary annuities, since the money typically arrives near the end of the pay or billing cycle.
Accumulation vs. Payout
This tool answers "how big will my balance grow?" — the accumulation phase. If you already have a lump sum or balance and instead want to know how much you can withdraw from it on a regular schedule without running out of money, use the annuity payout calculator instead. For a broader comparison of steady saving versus lump-sum investing strategies, the investment calculator can help.
Frequently Asked Questions
What is the difference between an ordinary annuity and an annuity due?
In an ordinary annuity, each deposit is credited at the end of the period, which is the standard setup for most retirement and savings contributions. In an annuity due, deposits are credited at the start of the period, giving each one an extra period to earn interest, which slightly increases the ending balance over long horizons.
Why does changing the compounding frequency change my results if my deposit amount stays the same?
Compounding frequency controls how often interest is calculated and added to your balance, independent of how often you deposit money. More frequent compounding (like daily versus annually) lets interest start earning its own interest sooner, which slightly increases your ending balance even if your contribution schedule doesn't change.