Compound Interest Calculator
Calculate compound interest on a lump sum plus monthly SIP contributions. See how your money grows with yearly, monthly and daily compounding.
Add a fixed amount saved every month to see the combined growth.
Maturity value
$196,715
After 10 year(s)
Total interest earned
$96,715
Interest + growth on investments
Total invested
$100,000
Your principal only
Your money grows by
96.7%
Gain over the total invested
How it works
A = P × (1 + r/n)^(n×t). SIP adds the future value of each monthly contribution.
Example: ₹1,00,000 at 7% yearly for 10 years → ₹1,96,715.
Last updated: September 2026
How this calculator is verified
Checked by Rahim Virani on
- Yearly, monthly and daily compounding verified against P(1+r/n)^(nt)
- Additional monthly contribution applied at period boundaries, not pro-rated mid-period
- Effective annual rate reported alongside nominal so the difference is visible
The full verification method is on our how we verify page. Found an error? Tell us and we will re-check it.
When to Use This Calculator
Use the compound interest calculator whenever you want to see what your money becomes when interest earns interest — the single most important idea in Indian personal finance. It answers questions like what a monthly SIP grows into over 20 years, or what a one-time lump sum becomes by retirement. Salaried investors use it to compare a recurring deposit, a mutual fund SIP and a fixed deposit on identical assumptions, since all three are compound growth with different rates. Enter the lump sum, monthly contribution, expected return and years, and read the corpus, the amount invested and the interest earned separately, so the growth card makes visible how much of the final figure is your own money versus compounding. Re-run it whenever the rate assumption changes.
How to Use This Calculator
- Step 1: Enter the starting lump sum, such as an amount you are moving into a deposit or mutual fund.
- Step 2: Enter the annual interest rate and the number of years you plan to stay invested.
- Step 3: Choose the compounding frequency: yearly, monthly or daily, since more frequent compounding grows the balance faster.
- Step 4: Optionally add a monthly SIP contribution to see the combined growth of the lump sum and the regular deposits.
Worked Example
A retiree in Chennai invests a lump sum of ₹1,00,000 at 8% per year compounded annually for 10 years. Enter 100000 as the principal, 8 as the annual rate and 10 as the years, keeping the compounding frequency at yearly. The maturity value is about ₹2,15,892, so the interest earned is about ₹1,15,892. Switching the frequency to monthly compounding raises the maturity value slightly, because interest is credited more often, and adding a monthly SIP contribution on top grows the total much faster.
Tips and Common Mistakes
- •Tip 1: For the same nominal rate, monthly compounding beats yearly compounding, so compare frequencies at the same rate before choosing a deposit.
- •Tip 2: Use the SIP field for recurring investments such as mutual fund contributions, since a lump-sum-only result understates the growth.
- •Tip 3: Tax treatment differs by product, so the gross figure shown is before tax on interest or capital gains.
- ✗Mistake 1: Entering a monthly rate when the calculator asks for the annual rate, which compounds the wrong number every period.
- ✗Mistake 2: Reading the maturity value as profit; the profit is maturity value minus the total money you put in.
Frequently Asked Questions
What is compound interest?
Compound interest is interest earned on both your original principal and the interest already added to it. Over time your money grows faster because each period's interest is calculated on a larger balance.
How is compound interest calculated?
The formula is A = P × (1 + r/n)^(n×t), where P is the principal, r is the annual rate as a decimal, n is the number of compounding periods per year and t is the time in years.
What is the difference between simple and compound interest?
Simple interest is only ever calculated on the original principal, so it grows linearly. Compound interest also earns interest on the interest, so the balance grows faster the longer it stays invested.
Why does compounding more frequently give higher returns?
The more often interest is added to your balance, the sooner it starts earning its own interest. Monthly compounding therefore returns slightly more than yearly compounding at the same nominal rate.
Can I use this for SIP and FD planning?
Yes. For a lump-sum fixed deposit, keep the monthly contribution at 0. For SIP planning, add a monthly amount to see the combined growth of a lump sum plus regular investments.
Does this account for tax on interest?
No. The result is the gross pre-tax value. Interest on fixed deposits is taxable at your slab rate, while equity mutual funds have their own capital-gains rules. Treat the output as a pre-tax estimate.
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