Compound Interest Calculator

Calculate compound interest with regular contributions, any compounding frequency, and inflation-adjusted results. Year-by-year table and growth chart included.

Runs in your browser

Investment details

$
%
$
Use a negative amount for regular withdrawals.
Contribution timing
%
Leave empty to skip the inflation-adjusted result.

Result

Final balance
$16,470.09
Total contributions
$0.00
Total principal
$10,000.00
Total interest
$6,470.09
Effective annual rate (APY)
5.116% nominal 5% compounded Monthly
Time to double
13 yr 11 mo rule of 72: 14 yr 5 mo
Formula
FV = 10,000 × (1 + 0.05/12)^(12 × 10) = $16,470.09

Interest is added on the contribution schedule, so a compounding frequency that differs from the deposit frequency is converted exactly.

Growth

Year 1: $10,511.62Year 2: $11,049.41Year 3: $11,614.72Year 4: $12,208.95Year 5: $12,833.59Year 6: $13,490.18Year 7: $14,180.36Year 8: $14,905.85Year 9: $15,668.47Year 10: $16,470.091610
Initial Contributions Interest $16,470.09

Year by year

YearContributionsInterestBalance
10.00511.6210,511.62
20.00537.7911,049.41
30.00565.3111,614.72
40.00594.2312,208.95
50.00624.6312,833.59
60.00656.5913,490.18
70.00690.1814,180.36
80.00725.4914,905.85
90.00762.6115,668.47
100.00801.6316,470.09

How to use

  1. Enter the initial amount, the annual interest rate and the term in years and months.
  2. Pick a compound frequency — daily, monthly, quarterly, annually or continuously.
  3. Add a contribution amount and frequency, and set its timing to end or beginning of period.
  4. Enter an inflation rate to also get the balance in today’s money, or leave it empty.
  5. Read the final balance and total interest, then use Copy table or Download CSV for the years.

FAQ

What is the compound interest formula?

FV = P × (1 + r/n)^(n×t). With regular deposits add PMT × ((1+i)^N − 1) / i, where i = r/n and N = n×t.

Does compounding frequency really matter?

Yes, but less than people expect. $10,000 at 5% for 10 years grows to $16,288.95 compounded annually and $16,470.09 compounded monthly — about $181 more.

Should deposits be at the beginning or end of the period?

Beginning-of-period deposits (an annuity due) earn one extra period of interest each time, so they always finish higher: $1,000 at 8% for 20 years with $200/year ends at $13,813.35 (end) vs $14,545.54 (beginning).

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