Introduction
Compound interest earns interest on both principal and previously accumulated interest — producing exponential growth over time. Savings accounts, mutual fund projections, and long-term investments typically use compounding at yearly, quarterly, or monthly intervals.
Numverto supports multiple compounding frequencies and shows year-wise growth. Study the math in our compound interest guide before trusting any financial decision to calculators alone.
Compound Interest Formula
A = P(1 + r/n)nt, where A = final amount, P = principal, r = annual rate (decimal), n = compounding periods per year, t = years. CI = A − P.
Step-by-Step Examples
Example: ₹1,00,000 at 10% compounded annually for 5 years
A = 100000 × (1.10)5 = ₹1,61,051. CI = ₹61,051.
Example: Quarterly compounding
n = 4. Rate per quarter = 10%/4 = 2.5%. More periods yield slightly higher A than annual compounding.
Real-Life Applications
- Fixed deposit and recurring deposit projections
- Retirement and SIP growth estimates
- Inflation-adjusted savings planning
- Finance and MBA coursework
- Comparing bank product interest rates fairly
Advantages of Using This Compound Interest
- Annual, half-yearly, quarterly, and monthly compounding
- Year-by-year balance table
- Visual comparison of SI vs CI when applicable
- Accurate power calculations for long tenures
- Free tool with no registration
Common Mistakes to Avoid
- Using percentage instead of decimal for r in the formula
- Wrong n for the stated compounding frequency
- Comparing products with different compounding without normalizing
- Ignoring taxes on interest income in net returns
- Assuming past compounded returns guarantee future results
Learn More
What is Compound Interest?
Compound interest is often called "interest on interest." Unlike simple interest, each interest payment is added to the principal, so the next period's interest is calculated on a larger amount. This creates exponential growth, the reason investments grow faster over longer periods.
Compound Interest Formula
A = P(1 + r/n)^(nt)
- A = Final amount
- P = Principal
- r = Annual interest rate (decimal)
- n = Compounding periods per year
- t = Time in years
Compound Interest = A - P
Effect of Compounding Frequency
More frequent compounding yields higher returns. ₹1,00,000 at 10% for 5 years:
- Yearly: ₹1,61,051
- Quarterly: ₹1,64,362
- Monthly: ₹1,64,530
- Daily: ₹1,64,866
Rule of 72
Divide 72 by the interest rate to estimate years to double your money. At 10% p.a., money doubles in approximately 7.2 years.
Applications
- Fixed deposits and recurring deposits
- Mutual fund SIP returns
- Loan interest (credit cards compound daily)
- Inflation impact on savings