Projection inputs
Build a growth projection
Change one assumption at a time to see how contributions, growth, and inflation affect the path.
This deterministic estimate does not model taxes, fees, volatility, or guaranteed returns.
Savings and investing
Compound Interest Calculator
Project compound growth with an initial balance, recurring contributions, contribution growth, and inflation context.
Compound growthMonthly contributionsSavings goal
Scenario planning
Saved scenarios
Save different assumptions locally and compare their projected outcomes.
No saved scenarios yet. Save the current assumptions to compare them later.
Projection result
Ending balance
$342,889.18
Total principal and deposits
$155,784.22
Interest and growth
$187,104.96
Inflation-adjusted balance
$189,849.42
Balance and contributions
| Year | Balance | Interest |
|---|---|---|
| Year 1 | $16,919 | $919 |
| Year 2 | $24,463 | $2,343 |
| Year 3 | $32,678 | $4,315 |
| Year 4 | $41,615 | $6,886 |
| Year 5 | $51,331 | $10,107 |
| Year 6 | $61,883 | $14,034 |
| Year 7 | $73,334 | $18,729 |
| Year 8 | $85,753 | $24,255 |
| Year 9 | $99,212 | $30,684 |
| Year 10 | $113,789 | $38,091 |
| Year 11 | $129,569 | $46,556 |
| Year 12 | $146,639 | $56,167 |
| Year 13 | $165,098 | $67,016 |
| Year 14 | $185,049 | $79,205 |
| Year 15 | $206,602 | $92,841 |
| Year 16 | $229,877 | $108,041 |
| Year 17 | $255,001 | $124,928 |
| Year 18 | $282,111 | $143,637 |
| Year 19 | $311,355 | $164,311 |
| Year 20 | $342,889 | $187,105 |
Read the projection
Separate deposits from growth
The projection records deposits and interest separately so you can see whether a target depends more on saving behavior or market assumptions. The savings mode also solves the monthly contribution implied by a target amount and horizon.
Model assumptions
Contributions are treated as end-of-month deposits. Annual rates are converted to an effective monthly rate for the projection, and inflation is shown as a purchasing-power context.
Planning estimate only. Returns are not guaranteed and actual investments can lose value.
Compound interest questions
Does compound interest include monthly contributions?
Yes. Deposits are added each month and are shown separately from interest and growth.
What does inflation-adjusted balance mean?
It expresses the projected balance in today's purchasing-power terms using the inflation assumption you enter.
Are investment returns guaranteed?
No. The result is a deterministic scenario, not a promise of future performance.
Need a change for Compound Interest Calculator?
About this calculator
Method, formulas, and limits.What this does
The Compound Interest Calculator converts the inputs you provide into a documented estimate with visible assumptions.
Who it is for
Anyone who wants a quick planning check before opening a spreadsheet or consulting a qualified professional.
How it works
The calculation runs locally in the browser using a pure TypeScript calculation function and the selected assumptions.
Limitations
Investment returns are not guaranteed. This projection does not model taxes, fees, volatility, or sequence-of-returns risk.
Key calculations
- Transparent model
- Inputs are normalized, calculated locally, and displayed with the underlying estimate rather than hidden rounding.
How to use it
- 1.Enter the inputsUse the form fields that match your scenario.
- 2.Review assumptionsRead the notes and formula explanation before relying on the result.
- 3.Compare scenariosChange one assumption at a time to understand sensitivity.
Investment returns are not guaranteed. This projection does not model taxes, fees, volatility, or sequence-of-returns risk.
No. The calculation is performed in your browser and the form does not send calculator inputs to a calculation service.
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