What is the Rule of 72?

It approximates how many years an investment takes to double: 72 ÷ annual return %. The Rule of 72 calculator shows that estimate instantly.

When should I use CAGR vs compound interest?

CAGR summarises growth between a start and end value over years. Compound interest projects a principal forward at a stated rate. Pick the tool that matches the question you have.

Can I use these for EMI or SIP math?

For loans and SIPs, prefer the dedicated EMI and SIP calculators — they use the right payment formulas. Everyday tools help with supporting percentage and inflation checks.

CalcMantra · India

Percentage, Interest & Everyday Math Calculators

Free percentage, discount, simple and compound interest, CAGR, inflation, and Rule of 72 calculators — quick INR-friendly math on CalcMantra.

These everyday CalcMantra tools cover the math behind discounts, growth rates, inflation drag, and doubling time. Use them alongside loan and SIP pages when you need a quick intermediate number.

They are general-purpose calculators: useful for school, shopping, and finance homework, with the same transparent formula style as our India money tools.

Compound interest CAGR Inflation Percentage

Compound Interest CalculatorFree compound interest calculator — compound a lump sum yearly, quarterly, or monthly.Open calculator →Simple Interest CalculatorFree simple interest calculator — interest on the original principal only using I = P × r × t.Open calculator →CAGR CalculatorFree CAGR calculator — compound annual growth rate between a start value and end value over years.Open calculator →Inflation CalculatorSee what today’s rupees become in future money, and the real return after inflation.Open calculator →Percentage CalculatorFree percentage calculator — what is x% of y, and what percent one number is of another.Open calculator →Discount CalculatorFree discount calculator — price after a percentage off MRP, with rupees saved.Open calculator →Rule of 72 CalculatorFree Rule of 72 calculator — rough years to double money using 72 ÷ annual return %.Open calculator →

Everyday calculators FAQs

What is the Rule of 72?: It approximates how many years an investment takes to double: 72 ÷ annual return %. The Rule of 72 calculator shows that estimate instantly.
When should I use CAGR vs compound interest?: CAGR summarises growth between a start and end value over years. Compound interest projects a principal forward at a stated rate. Pick the tool that matches the question you have.
Can I use these for EMI or SIP math?: For loans and SIPs, prefer the dedicated EMI and SIP calculators — they use the right payment formulas. Everyday tools help with supporting percentage and inflation checks.

Looking for scenario answers with tables? See popular finance questions or the calculator guides.