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Compound interest + future value
Project a savings/investment balance with monthly compounding + monthly contributions.
What this is
The 8th wonder of the world
Compound interest = earning interest on your interest. The longer the time horizon, the more dramatic the growth. This is the single most powerful concept in personal finance.
- ·$500/mo at 7% return for 30 years → ~$612,000. You contributed $180k; compound interest delivered the other $432k.
- ·Rule of 72: years to DOUBLE = 72 ÷ rate%. At 7%, money doubles every ~10.3 years.
- ·CAGR (Compound Annual Growth Rate) = the steady annual return that gets you from the starting amount to the ending amount.
Future value
$300,851
Total contributed
$130,000
Interest earned
$170,851
Implied CAGR
4.28%
At 7.0% annual return, money doubles every ~10.3 years (Rule of 72).
Balance growth over time
Contribution vs growth at year 20
Educational projection. Real returns are noisy and taxes + fees erode the headline rate. For RRSP/TFSA growth, use the marginal-tax-aware calculators instead.