Compound Interest Calculator

Calculate compound interest with different compounding frequencies — monthly, quarterly, annually. See the power of compounding over time with interactive charts.

Compound Interest Calculator

Monthly, quarterly, annual compounding — the magic of earning interest on interest

Principal amount Rs 1,00,000
Rs 1KRs 1Cr
Rs
Annual interest rate 12%
1%30%
%
Time period 10 years
1 yr40 yr
yrs
Compounding frequency
Total amount
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principal + CI
Compound interest
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earned on interest too
CI beats SI by
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compounding advantage
Principal---
Rate (nominal)---
Compounding frequency---
Compound interest earned---
Simple interest (for comparison)---
Rule of 72 — doubles in---
Total amount---
Principal vs compound interest earned
Principal: ---
CI earned: ---

Estimates for personal financial planning. Consult a financial advisor for personalised advice.

Principal vs CI growth over time
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ThriftRupee Insight

Einstein allegedly called compound interest the "eighth wonder of the world." Rs 1 lakh at 12% for 30 years = Rs 29.96 lakh with annual compounding, Rs 35 lakh with monthly compounding — a Rs 5 lakh difference just from compounding frequency. The lesson: reinvest returns immediately, choose monthly-compounding instruments, and give time maximum opportunity to work.

Compound Interest Calculator — Earn Interest on Interest

Compound interest is the foundation of wealth creation. Unlike simple interest (calculated only on principal), CI earns interest on accumulated interest too. At 12% compounded monthly, Rs 1 lakh grows to Rs 3.3 lakh in 10 years — vs Rs 2.2 lakh under simple interest.

Frequently asked questions

What is the compound interest formula?▼
A = P × (1 + r/n)^(n×t), where A = final amount, P = principal, r = annual interest rate (decimal), n = number of times interest compounds per year, t = time in years. CI = A − P. For monthly compounding (n=12), a 12% annual rate becomes 1% monthly, leading to 12.68% effective annual rate (EAR).
What is the Rule of 72?▼
Rule of 72: divide 72 by the annual interest rate to get the approximate number of years to double your money. At 12% → 72/12 = 6 years to double. At 8% → 72/8 = 9 years. At 6% → 72/6 = 12 years. This works well for rates between 6-20%. It is a quick mental math tool for comparing investment options.
Monthly compounding vs annual compounding — which is better?▼
Monthly compounding is always better for investors (but worse for borrowers). At 12% annual rate: Annual compounding = 12% effective rate. Monthly compounding = 12.68% effective annual rate. The more frequently interest compounds, the higher the effective return. FDs in India compound quarterly, not monthly — this is why the effective rate is higher than the nominal rate.

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