Compound interest calculator
₹1,00,000 today plus ₹5,000 a month, at 12% a year for 10 years, becomes ₹14,72,280 — ₹3,10,585 from the starting amount and ₹11,61,695 from the monthly additions. Most compound interest calculators only handle one of those two.
Principal, additions, frequency
What leaves your bank account every month. Type any amount — the slider is just a shortcut.
An assumption, not a promise. Equity funds are usually modelled at 10–12%; see what rate to assume.
What it becomes
What you investWhat compounding adds
| Year | Invested | Returns | Value at year end |
|---|---|---|---|
| 1 | ₹1,60,000 | ₹16,047 | ₹1,76,047 |
| 2 | ₹2,20,000 | ₹41,656 | ₹2,61,656 |
| 3 | ₹2,80,000 | ₹78,031 | ₹3,58,031 |
| 4 | ₹3,40,000 | ₹1,26,526 | ₹4,66,526 |
| 5 | ₹4,00,000 | ₹1,88,666 | ₹5,88,666 |
| 6 | ₹4,60,000 | ₹2,66,167 | ₹7,26,167 |
| 7 | ₹5,20,000 | ₹3,60,963 | ₹8,80,963 |
| 8 | ₹5,80,000 | ₹4,75,229 | ₹10,55,229 |
| 9 | ₹6,40,000 | ₹6,11,415 | ₹12,51,415 |
| 10 | ₹7,00,000 | ₹7,72,280 | ₹14,72,280 |
The two formulas at work
This page adds two separate calculations, which is why it can split the result:
- The principal:
P × (1 + r ÷ m)m × t, where m is how many times a year interest is compounded. - The monthly additions: the annuity-due formula, the same one a SIP uses.
Compounding frequency matters less than people expect. ₹1,00,000 at 12% for 10 years gives ₹3,10,585 compounded yearly against ₹3,30,039 compounded monthly. Real, but a rounding error next to the effect of adding a few more years.
The rule of 72, and where it breaks
Divide 72 by your annual rate and you get, roughly, the years to double. At 12% that is 6 years; the exact answer is 6.12. Close enough for mental arithmetic.
It degrades at the extremes. At 2% the rule says 36 years and the truth is 35.0. At 30% it says 2.4 and the truth is 2.64. Fine between roughly 5% and 15%, which covers most real decisions.
Before you rely on this
An estimate, not a forecast
This is arithmetic applied to assumptions you chose. Mutual funds carry market risk, returns are not guaranteed, and past performance does not indicate future results. Nothing here is personalised advice — for decisions of any size, speak to a SEBI-registered investment adviser.
Questions people actually ask
What is the difference between simple and compound interest?
Simple interest pays only on the original principal, so ₹1,00,000 at 10% pays ₹10,000 every year forever — ₹2,00,000 after ten years. Compound interest pays on the accumulated balance, so the same money reaches about ₹2,59,374.
The gap widens with time, which is the entire point. Over thirty years compound produces several times what simple does.
Does compounding frequency make a big difference?
Less than most people assume. Going from annual to monthly compounding at 12% adds about 0.68 percentage points of effective rate. Going from monthly to daily adds a few hundredths.
Duration and contribution size dominate. Frequency is a detail.
Can I use this for a fixed deposit or a loan?
For a deposit, yes — set additions to zero and pick quarterly compounding, which is the Indian bank convention. The FD calculator is set up for that already.
For a loan you need amortisation rather than plain compounding, because you are paying principal down each month. Use the sibling home loan EMI calculator.