Interest Calculator
Calculate simple and compound interest to see how your savings or investments grow over time. Add optional monthly contributions, choose your compounding frequency, and instantly see your future value and total interest earned.
Secure & Private Client-Side
This tool runs entirely in your browser. No data is sent to any server, ensuring your information remains private and secure.
About Interest Calculator
Calculate simple and compound interest to see how your savings or investments grow over time. Add optional monthly contributions, choose your compounding frequency, and instantly see your future value and total interest earned.
Frequently Asked Questions
What is the difference between simple and compound interest? expand_more
Simple interest is calculated only on the original principal. Compound interest is calculated on the principal plus any previously earned interest, so it grows faster. Toggle between both modes in the [Interest Calculator](/tools/interest-calculator/).
How does compounding frequency affect growth? expand_more
The more often interest compounds (daily vs. annually), the more you earn, because interest starts earning its own interest sooner. The difference is small at low rates but grows significantly over long periods.
Can I include monthly contributions? expand_more
Yes! Add a recurring monthly contribution to model a SIP or systematic savings plan. The tool computes the future value of your contributions alongside your initial principal.
What is the compound interest formula? expand_more
The formula is A = P(1 + r/n)^(nt), where P is principal, r is the annual rate, n is the number of times interest compounds per year, and t is the number of years.
Is this calculator accurate for real investments? expand_more
It gives a solid estimate assuming a constant rate of return. Real investments fluctuate, and the tool does not account for taxes, fees, or inflation. Use it for planning, not as financial advice.
Common Use Cases
- Investment Growth: See how a lump sum grows with compound interest over years of saving.
- Recurring Savings: Add a monthly contribution to project the future value of a SIP or savings plan.
- Compare Compounding: Switch between annual, monthly, and daily compounding to see the difference.
- Simple Interest: Toggle simple-interest mode for fixed deposits, bonds, or short-term loans.