Quick calculator · ≈ 1 min · Saving & growth
Compound Growth Calculator
Watch how a starting amount and steady monthly contributions grow over time.
Showing example defaults — change any input to use your own
Growth projection
Balance after 25 years
$391,147
You'd put in $160,000 total; compounding at 6% adds $231,147 on top — 144% more than you contributed.
- Total contributions
- $160,000
- Growth earned
- $231,147
- Doubling time (Rule of 72)
- ≈ 12 years
Balance vs. contributions
View data table
| Balance | Contributions | |
|---|---|---|
| Yr 0 | $10K | $10K |
| Yr 2 | $24K | $22K |
| Yr 4 | $40K | $34K |
| Yr 6 | $58K | $46K |
| Yr 8 | $78K | $58K |
| Yr 10 | $100K | $70K |
| Yr 12 | $126K | $82K |
| Yr 14 | $154K | $94K |
| Yr 16 | $187K | $106K |
| Yr 18 | $223K | $118K |
| Yr 20 | $264K | $130K |
| Yr 22 | $310K | $142K |
| Yr 24 | $363K | $154K |
| Yr 25 | $391K | $160K |
What this may mean for you
The gap between the lines is compounding — small early, then dominant. It's why starting matters more than optimizing: a year of delay costs you your best year of growth, the last one.
Results are estimates for educational purposes and may not reflect your complete financial or tax situation.
Understanding this calculator
Compounding is growth earning growth. Early on, your contributions dominate the balance; give it a decade or two and the growth line takes over, which is why the same monthly amount is worth so much more to a 35-year-old than a 55-year-old. The chart's split between contributions and growth makes that handoff visible.
A handy mental shortcut is the Rule of 72: divide 72 by your return to estimate doubling time. At 6%, money doubles about every 12 years — so a dollar invested 36 years before retirement has three doublings ahead of it.
Assumptions and methodology
- Monthly compounding at your annual rate, contributions added at month-end.
- Taxes, fees, and volatility are not modeled — this is the smooth-curve view of growth.
Last reviewed August 30, 2026. Year-specific figures show their tax or data year in the tool; data is reviewed when the IRS, SSA, and CMS publish annual updates.
Common questions
Why monthly compounding?
It matches how most people save (per paycheck or per month) and closely approximates continuous market growth for planning purposes.
Next step
See how this fits your whole retirement
One number is a start. The plan builder puts income, spending, savings, and taxes together year by year — free, no account, and every answer can be changed later.
Keep going
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- InflationSee what today's expenses could cost in the future — and what future dollars are worth today.Calculator
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