Most PPF calculators assume you put the whole year's money in on day one. Many people actually pay monthly, and PPF pays interest in a particular way: on the lowest balance between the 5th and the end of each month, added once a year. This free Excel sheet does both, and runs the account past 15 years in 5-year extensions.
⬇ Download: PPF calculator in Excel (.xlsx, free)What's in the sheet
- Yearly tab: your yearly deposit, the rate, and how many 5-year extensions you want (0 closes the account at 15 years, 2 runs it to 25), with or without deposits during the extension.
- A year-by-year table: opening balance, deposit and closing balance for up to 50 years.
- Monthly tab: a fixed deposit every month by the 5th, worked out on the monthly-balance rule, next to what the same money earns if paid once by 5 April.
- The old-regime tax saving on the yearly deposit.
The formula, so you can check it
If you deposit the full amount by 5 April each year, the year's interest is the whole balance × rate, so the closing balance is (opening balance + deposit) × (1 + rate). In Excel that is =(B+C)*(1+7.1%) down a column. With ₹1,50,000 a year at 7.1%, 15 years comes to ₹40,68,209: ₹22,50,000 deposited and ₹18,18,209 of tax-free interest. Keep depositing for two 5-year extensions and 25 years comes to about ₹1.03 crore.
With monthly deposits, each one earns interest only for the months it was in the account by the 5th. ₹12,500 a month (the same ₹1,50,000 a year) for 15 years comes to ₹39,44,599, about ₹1.24 lakh less than paying the year's money by 5 April. Pay after the 5th and that month earns nothing on the new money.
Source: Small savings rates for Oct–Dec 2026: PPF 7.1% (Business Today, 30 Sep 2026)
Rules worth knowing before you plan
- Deposits: ₹500 to ₹1,50,000 a financial year. Missing the minimum makes the account inactive until you pay a small penalty.
- The account matures after 15 full financial years, counted from the end of the year you opened it.
- After that you can extend in 5-year blocks, with deposits or without. Without deposits the balance keeps earning interest.
- The rate is set by the government every quarter, so a 15-year plan is an estimate. 7.1% has held since 2020.
- Interest and maturity are tax-free. Deposits get the old-regime deduction up to ₹1.5 lakh a year; the new regime gives none.
Frequently asked questions
- How do I calculate PPF in Excel?
- Make a year column, then closing balance = (opening balance + deposit) × (1 + rate), with each year's opening balance equal to the last year's closing balance. That assumes you deposit by 5 April. The free sheet on this page has it set up, plus a monthly tab.
- How much will ₹1.5 lakh a year in PPF become in 15 years?
- About ₹40.68 lakh at 7.1%, if you deposit by 5 April every year. ₹22.5 lakh of that is your money and the rest is tax-free interest.
- Is it better to deposit in PPF yearly or monthly?
- Paying the year's amount by 5 April earns the most, because every rupee earns interest for the full year. Monthly deposits by the 5th earn a little less; deposits after the 5th miss that month's interest.
- Can I continue PPF after 15 years?
- Yes, in blocks of 5 years, with or without fresh deposits. Set the extension cell in the sheet to see 20, 25 or 30 years.