Compound Interest Calculator
A savings account or investment that compounds interest grows faster than simple interest over time, because each period's interest gets added back to the principal and starts earning its own interest. This calculator works out exactly how much a deposit grows under compound interest, factoring in how often the interest compounds.
Why compounding frequency changes the result
The same annual interest rate produces a different final amount depending on how often it compounds — monthly compounding grows money slightly faster than annual compounding at the same stated rate, because interest gets added back to the principal (and starts earning its own interest) more frequently. The formula used is Amount = Principal × (1 + rate/100/n)^(n×time), where n is the number of compounding periods per year.
Where this calculation is useful
Projecting how a fixed deposit or savings account will grow over several years at a bank's advertised compound rate. Comparing two investment products with the same headline interest rate but different compounding frequencies (annual vs. monthly) to see which actually earns more. Understanding roughly how a long-term investment like a retirement fund might grow under compound returns, as a simplified starting estimate before consulting a financial advisor for a full plan.
Frequently Asked Questions
Which compounding frequency should I select if I'm not sure? Check your bank or investment product's terms and conditions — it will state whether interest compounds annually, semi-annually, quarterly, or monthly; when unsure, annual compounding is the most conservative (lowest growth) estimate.
Does this account for additional regular deposits over time? No — this calculates growth from a single lump-sum principal only; regular additional contributions would need a more advanced calculator that factors in periodic deposits.
Is my financial data saved anywhere? No — the calculation runs entirely in your browser using JavaScript; nothing is stored or transmitted.