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Formula & explanation
Interest Calculator uses the following calculation:
This is a simplified model intended for planning and education. Real-world offers from lenders, institutions, or tax authorities may include additional fees, rules, or adjustments not reflected here.
Frequently asked questions
What's the difference between simple and compound interest?
Simple interest is calculated only on the principal, while compound interest is calculated on the principal plus any interest already earned — so it grows faster over time.
How much does compounding frequency matter?
More frequent compounding (daily vs. annually) slightly increases returns at the same stated rate, though the effect is usually modest compared to the rate and time horizon.
What's the biggest lever for growing my balance?
Time in the market and consistent contributions typically matter more than trying to time the best rate.