Calculate simple interest, total interest earned, and maturity value from your principal, interest rate, and investment duration with instant results and a clear growth projection.
Optimizing tool for speed and clarity
Calculate simple interest, total interest earned, and maturity value instantly. No accounts, no tracking, just calculations.
Currency affects display only — no exchange-rate conversion is applied.
Note: Estimates only, based on standard interest formulas. Actual financial products may differ due to product terms, taxes, fees, or calculation methods. Confirm exact figures with your financial institution.
Calculate simple interest and the total maturity value on a principal amount. Enter your principal, annual interest rate, and duration in years to see exactly how much interest accrues without any compounding.
This calculator is useful for estimating short-term loans, basic savings scenarios, or any situation where interest is calculated only on the original amount. Results are estimates — confirm exact figures with your bank or lender.
Estimate the total interest earned or owed over the selected duration.
See the principal plus interest combined into a single maturity figure.
Model different principal amounts, interest rates, and durations up to 100 years.
See a year-by-year chart of how the value grows over the investment period.
Review the principal, interest, and maturity value together.
Calculate simple interest from phones, tablets, laptops, or desktop browsers.
Enter the starting amount you're investing or lending.
Enter the annual simple interest rate applicable to your scenario.
Enter how long the amount stays invested, in years, up to 100.
Check the estimated total interest and the maturity value.
This calculator is built for anyone who needs a quick, no-compounding interest estimate.
The standard simple-interest formula is:
I = P × r × t
I = interest earned
P = principal amount
r = annual interest rate expressed as a decimal
t = time in years
Maturity value is the principal plus the calculated interest: A = P + I. Actual financial products may use different rules or add fees.
Suppose you invest ₹1,00,000 at an annual simple interest rate of 7% for five years. Using I = P × r × t with P = 1,00,000, r = 0.07, and t = 5, the interest earned is ₹35,000, giving a maturity value of ₹1,35,000.
This example matches the calculator's default values above, so you can verify it yourself: ₹35,000 interest on ₹1,35,000 total.
| Factor | Simple Interest | Compound Interest |
|---|---|---|
| How interest is earned | Only on the original principal | On principal plus previously earned interest |
| Growth over time | Linear — grows by the same amount each year | Accelerating — grows faster each period |
| Formula | I = P × r × t | A = P(1 + r/n)^(nt) |
| Typical use case | Short-term loans, simple savings estimates | Bank deposits, long-term investments |
Want to see how compounding changes the outcome, or plan a fixed or recurring deposit instead? Try our other savings calculators.
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A simple interest calculator estimates the interest earned or owed on a principal amount using a fixed rate applied only to the original principal, without compounding.
Simple interest is calculated as I = P × r × t, where P is the principal, r is the annual interest rate as a decimal, and t is the time in years.
Simple interest is earned only on the original principal for the entire period. Compound interest is earned on the principal plus any interest already added, so it grows faster over time.
You need the principal amount, the annual interest rate, and the time period over which interest is calculated.
Yes, for this calculator the duration is entered in years. If you have a period in months, convert it to years first (for example, 6 months is 0.5 years).
Yes, some loans and short-term financial products use simple interest. However, many loans use amortizing or compound structures, so check the specific product's terms.
The result depends on the interest rate you enter. Use the calculator with ₹1,00,000 as the principal, your expected rate, and 5 years to see the estimated interest and total value.
Yes, for simple interest, interest earned increases linearly with time when the principal and rate stay the same, since it isn't affected by compounding.
Yes, you can use it to estimate a simple-interest scenario in any currency, including INR. Confirm the actual terms with your bank or lender, since real products may use different rules.
Interest income can be taxable under applicable tax rules depending on your jurisdiction and circumstances. This calculator estimates interest and does not calculate personal tax liability.
Yes. The calculator is free to use and does not require registration.
No. The calculator runs entirely in your browser — the numbers you enter are used only to compute the result on your device and are not uploaded or saved.
Yes, use the export button above the projection chart to generate a PDF report of your principal, rate, duration, and results.
Results are estimates based on the values entered and the standard simple-interest formula. Actual financial products may differ because lenders and institutions can use different rates, day-count conventions, fees, or calculation rules. Confirm the applicable terms with the relevant institution before making a decision.