Project how money grows with compound interest across compounding frequencies, with or without regular contributions, and see the balance for every single year. Runs entirely in your browser — your numbers never leave this device.
| Year | Balance | Contributed | Interest earned |
|---|---|---|---|
| 1 | $1,051.16 | $1,000.00 | $51.16 |
| 2 | $1,104.94 | $1,000.00 | $104.94 |
| 3 | $1,161.47 | $1,000.00 | $161.47 |
| 4 | $1,220.90 | $1,000.00 | $220.90 |
| 5 | $1,283.36 | $1,000.00 | $283.36 |
| 6 | $1,349.02 | $1,000.00 | $349.02 |
| 7 | $1,418.04 | $1,000.00 | $418.04 |
| 8 | $1,490.59 | $1,000.00 | $490.59 |
| 9 | $1,566.85 | $1,000.00 | $566.85 |
| 10 | $1,647.01 | $1,000.00 | $647.01 |
| Annual rate | Value after 10 years | Interest earned |
|---|---|---|
| 3% | $1,343.92 | $343.92 |
| 5% | $1,628.89 | $628.89 |
| 7% | $1,967.15 | $967.15 |
| 10% | $2,593.74 | $1,593.74 |
Compound interest means each period's interest is added to the balance, so the next period earns interest on the interest as well as on the original money. Growth therefore accelerates: the balance curve bends upwards over time instead of rising in a straight line. The calculator applies the growth period by period and prints the balance at the end of every year, so you can watch the acceleration in the actual numbers rather than trusting a single final figure.
Compounding frequency matters, but less than people expect. The same rate compounded monthly produces a slightly higher final balance than the same rate compounded annually, because interest starts earning its own interest sooner. Daily compounding adds a little more again. The examples below quantify the gap on the same deposit so you can see it is real but modest — the rate and the number of years move the result far more than the frequency does.
Regular contributions are handled as an annuity on top of the lump sum: each contribution compounds for the time it is actually invested, so early contributions grow the most. The calculator keeps the two parts visible — what you put in versus what growth added — because a final balance that is mostly your own deposits tells a very different story from one that is mostly growth.
Simple interest is paid only on the original principal; compound interest is paid on the principal plus all interest already earned. On $1,000 at 5% for 10 years, simple interest earns a flat $50 a year for $1,500 total, while compounding reaches $1,628.89 — and the gap widens every year because the compound balance keeps growing.
Less than the rate or the time period. At 5% over 10 years on $1,000, annual compounding gives $1,628.89, monthly gives ≈ $1,647.01 and daily would give a little more again — differences of tens of dollars. Raising the rate from 5% to 7%, by contrast, lifts the annual-compounding result to $1,967.15. Frequency is a fine-tuning knob, not the engine.
Because interest is a percentage of the current balance. At 5%, a $1,000 balance gains $50 in a year; a $10,000 balance gains $500 in a year at the same rate. Early on the balance is small so the gains are small, but every gain permanently enlarges the base the next percentage is applied to.
A shortcut for doubling time: divide 72 by the annual rate (as a percentage) to estimate the years needed for money to double. At 5% that is 72 / 5 = 14.4 years — check the table logic: $1,000 at 5% reaches $1,628.89 in 10 years and would pass $2,000 at about year 14. At 10% it doubles in about 7.2 years, which fits the table above: $1,000 at 10% passes $2,000 during year 8 and reaches $2,593.74 by year 10.
No. It projects the nominal balance from the rate you enter. Tax on interest and inflation both reduce what the final balance is really worth; if you want a rough real-terms figure, enter a rate net of your expected inflation (for example 5% growth with 3% inflation behaves roughly like 2% real growth) or use the Inflation Calculator alongside this one.
No. The projection runs entirely in your browser — nothing you type is uploaded, stored or tracked, and closing the page clears everything.
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