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Compound vs Simple Interest Comparison
Compound vs simple interest table over 1–30 years.
Simple interest applies only to the original principal. Compound interest reinvests earnings. The gap widens dramatically over long horizons.
$10,000 principal at 7% annual rate — simple vs compound (monthly)
| Years | Simple Interest (7%) | Compound Interest (7%, monthly) | Difference |
|---|---|---|---|
| 1 | $10,700 | $10,723 | $23 |
| 5 | $13,500 | $14,176 | $676 |
| 10 | $17,000 | $20,097 | $3,097 |
| 20 | $24,000 | $40,387 | $16,387 |
| 30 | $31,000 | $81,007 | $50,007 |
Rule of 72
Divide 72 by the annual rate to estimate years to double: at 7%, money doubles in roughly 72/7 ≈ 10.3 years with compound interest.
Frequently asked questions
How do I use this Compound Interest reference?
Find your category or range in the table, then use the linked calculator to compute an exact value for your inputs.
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Compound Interest Calculator