Compound Interest Calculator
Finance & InvestmentSee what compounding turns your money into, and what it adds over simple interest.
Runs entirely in your browser — nothing is uploaded
Features
- Yearly, half-yearly, quarterly or monthly compounding.
- Shows simple interest beside it, so you can see what compounding adds.
- Effective annual return, not just the headline rate.
- Works for deposits, loans and any growing balance.
- Runs entirely in your browser — nothing you enter is uploaded.
How to use the Compound Interest Calculator
- 1Enter the principal, the rate and how long it is invested.
- 2Pick how often interest is added — this matters more than people expect.
- 3Compare the compound and simple figures to see the difference.
Frequently asked questions
What is the compound interest formula?
A = P(1 + r/n)^(nt), where P is the principal, r the annual rate as a decimal, n how many times a year interest is added, and t the number of years. The interest earned is A − P. The calculator does this and also shows the simple-interest figure for comparison.
Why does compounding frequency change the answer?
Because each time interest is added it starts earning interest itself. At 10% on ₹1,00,000 for five years, yearly compounding gives ₹1,61,051 and monthly gives ₹1,64,531 — same rate, different result. It is why two products quoting the same rate can pay differently.
What is the difference between compound and simple interest?
Simple interest is always calculated on the original principal, so it grows in a straight line. Compound interest is calculated on the balance including past interest, so it accelerates. Over short periods the gap is small; over twenty years it is usually larger than the principal itself.
What does the effective annual return mean?
It is the single yearly rate that would produce the same final amount. When interest compounds more often than yearly, the effective return is higher than the quoted rate — that is the number to compare two products with.