Compound Interest Calculator
Calculate future value with compound interest, periodic contributions (SIP), and growth charts.
Financial
Compound Interest Calculator
Generated on April 25, 2026
Add periodic contributions (SIP / monthly savings)
Future Value after 10 years
$22,196
Principal
$10,000
Total Interest
$12,196
Year-by-Year Growth
Step-by-step calculation
Formula
FV = P(1 + r/n)^(nt) + PMT × [((1 + r/c)^(ct) − 1) / (r/c)]
- 1Principal P = $10,000
- 2Annual rate r = 8% = 0.0800
- 3Compounded monthly (n = 12 times per year)
- 4Time t = 10 years
- 5No periodic contributions
- 6Future value = $22,196
- 7Total interest earned = $22,196 − $10,000 − $0 = $12,196
?What is the Compound Interest Calculator?
The Compound Interest Calculator computes the future value of an investment that earns interest on both the initial principal and the accumulated interest from previous periods — the famous 'interest on interest' that Einstein reportedly called the eighth wonder of the world. It supports periodic contributions (SIPs, monthly savings, retirement deposits), multiple compounding frequencies (daily, monthly, quarterly, annually), and renders a year-by-year growth chart that visually separates principal, contributions, and interest earned. This is the foundation of every long-term investing decision: a small amount saved monthly for 30 years, compounded at a reasonable rate, dwarfs much larger sums saved for shorter periods.
The Formula
The first term is the future value of the lump-sum principal compounding at rate r/n every period for nt total periods. The second term is the future value of a series of equal periodic contributions (an annuity), assuming each contribution earns interest from the moment it's deposited. The compounding frequency matters: $10,000 at 8% for 10 years yields $21,589 if compounded annually, $22,196 if compounded monthly, $22,253 if compounded daily — the difference shrinks as compounding gets more frequent (the limit being continuous compounding: P × e^(rt)).
Future value of $10,000 at 8% annual return, compounded monthly
How time and additional monthly contributions transform a starting investment.
| Years | No contributions | +$100/mo | +$500/mo | +$1,000/mo |
|---|---|---|---|---|
| 5 | $14,898 | $22,254 | $51,679 | $88,460 |
| 10 | $22,196 | $40,475 | $113,712 | $204,260 |
| 15 | $33,069 | $67,650 | $206,781 | $381,996 |
| 20 | $49,268 | $108,164 | $345,514 | $646,495 |
| 25 | $73,402 | $168,553 | $552,277 | $1,040,679 |
| 30 | $109,357 | $258,567 | $860,431 | $1,627,929 |
Put It in Perspective
If Christopher Columbus had invested $1 in 1492 at 6% annual return, today (~530 years later) it would be worth $13 quadrillion — more than all global wealth combined. (This illustrates why compound interest is so powerful — and why it doesn't actually scale infinitely in practice.)
Warren Buffett earned 99% of his net worth after age 50 — proof that compound interest rewards patience above all else.
$1 saved per day at 7% return becomes $109,000 over 50 years.
Practical Examples
$10,000 invested at 8% annual return, compounded monthly for 30 years, grows to $108,920 — over 10× the original.
Saving $500/month for 25 years at 7% return reaches $396,000 — total contributions of $150K plus $246K of compound growth.
The 'Rule of 72' approximation: divide 72 by your annual rate to estimate doubling time. At 8%, money doubles roughly every 9 years.
A 25-year-old who saves $200/month until 65 at 7% return retires with ≈$525,000 from total contributions of just $96,000.
Pakistan National Savings Scheme (Bahbood / Pensioners) historically yields 11–13% — at 12%, an investment doubles every 6 years.
Islamic finance alternative: profit-sharing accounts (Mudarabah) compound similarly but with returns based on actual business profit, not a fixed interest rate.
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