Annuity accumulation calculator with contribution timing
Combine a starting amount with periodic and annual deposits. The result separates cash contributed from modeled growth and provides a year-by-year accumulation schedule.
Inputs used by this calculator
Annuity Calculator uses the fields below. The starting values reproduce the page example; replace them with values from the same units and time period before using the result.
| Input | Starting example | Accepted value | How it is used |
|---|---|---|---|
| Starting principal ($) | 10,000 | 0 to 1000000000000 | Supplies the starting principal ($) quantity used by the published equation or result breakdown. |
| Annual addition ($) | 5,000 | 0 to 1000000000 | Supplies the annual addition ($) quantity used by the published equation or result breakdown. |
| Deposit each period ($) | 300 | 0 to 1000000000 | Supplies the deposit each period ($) quantity used by the published equation or result breakdown. |
| Annual return (%) | 6 | -99 to 100 | Supplies the annual return (%) quantity used by the published equation or result breakdown. |
| Years | 10 | 1 to 100 | Supplies the years quantity used by the published equation or result breakdown. |
| Deposit and compounding frequency | Monthly | Monthly · Quarterly · Annually | Supplies the deposit and compounding frequency quantity used by the published equation or result breakdown. |
| Deposits made | At end of period | At end of period · At beginning of period | Supplies the deposits made quantity used by the published equation or result breakdown. |
What this annuity calculator models
This page covers the accumulation phase: money is added over time and earns a constant entered rate. Use Annuity Payout Calculator when an existing balance is being converted into withdrawals.
Accumulation formulas
The annual nominal rate is divided by the selected frequency. The engine simulates every period so monthly deposits and a separate annual addition can coexist without hiding timing assumptions.
periodic rate=annual rate÷periods per yearending balance=starting balance+deposits+modeled interestBeginning versus end deposits
A beginning deposit earns interest during the period in which it is made. An end deposit begins earning in the following period. The difference compounds across the term.
Worked contribution example
With $10,000 initially, $300 monthly and $5,000 annually, the table shows each year's deposits, interest and ending value. Cash contributed stays separate from growth.
Annuity contracts versus the math
An annuity product may include insurer guarantees, expenses, surrender charges, riders, tax rules and payout elections. This calculator models cash flows only and does not evaluate a contract.
Testing realistic scenarios
Compare lower and higher return assumptions and add known fees by reducing the entered net rate. Constant returns smooth out market volatility, so the schedule is an illustration rather than a forecast.
Accumulation inputs
| Input | Effect |
|---|---|
| Starting principal | Receives growth from the first period |
| Periodic addition | Repeats at the selected frequency |
| Annual addition | Occurs once per year |
| Deposit timing | Controls whether new cash earns that period |
| Annual rate | Constant nominal scenario |
Frequently asked questions
Is this the same as an annuity payout calculator?
No. This tool accumulates deposits; the payout tool draws down an existing balance.
Are deposits monthly by default?
Yes. You can change the frequency to quarterly or annual.
When is the annual addition made?
It follows the selected beginning-or-end deposit convention once each year.
Are fees included?
Only if you incorporate them into the net return entered.
Is the return guaranteed?
No. It is a constant scenario supplied by the user.
Does this evaluate an insurance annuity contract?
No. Contract guarantees, fees, taxes and surrender terms require separate review.
What to keep in mind
This is a deterministic accumulation scenario, not a quote, guarantee or investment recommendation. It excludes taxes, fees, changing returns and product-specific surrender or insurance terms.
Results are rounded for display in US format, with money in dollars and cents; CSV exports keep full calculation precision. This is a calculation summary, not an official certificate.