How to use this PPF calculator
Enter what you plan to pay in each financial year, from ₹500 to ₹1,50,000. The ₹1,50,000 limit covers your own account and any you run for a minor, together. The rate starts at 7.1%, the rate for October to December 2026. The government resets it every quarter, so a long projection at one rate is an estimate.
Choose a lump sum by 5 April or twelve equal monthly deposits, each by the 5th. Total period counts financial years of deposits: 15 is the standard term, and each step above it adds a five-year extension with deposits. The calculator assumes no loans or withdrawals.
How PPF interest is calculated
Under the PPF Scheme, 2019, each month earns interest on the lowest balance between the close of the 5th day and the end of the month. The monthly amounts are added up and credited once, at the end of the financial year, so interest compounds yearly. Money paid in on the 6th or later earns nothing for that month.
Take an opening balance B, a yearly deposit D and a rate r. A lump sum by 5 April earns (B + D) × r for the year. Twelve deposits of D ÷ 12 earn each month's balance × r ÷ 12, added up, which comes to B × r + D × r × 13 ÷ 24. Over n years of lump sums the balance is D × (1 + r) × ((1 + r)^n − 1) ÷ r.
Worked example: ₹1,50,000 a year at 7.1%
Paid by 5 April, the first deposit earns ₹10,650.00 in year one, so the account holds ₹1,60,650.00 on 31 March. With 1.071^15 at about 2.7980, the 15-year factor is about 27.1214, and the account matures at ₹40,68,209.22. You pay in ₹22,50,000, so the interest is ₹18,18,209.22.
Paid as ₹12,500 by the 5th of each month, the same money earns ₹5,768.75 in year one: the monthly balances run from ₹12,500 to ₹1,50,000 and add up to ₹9,75,000. After 15 years the account holds ₹39,44,599.22, which is ₹1,23,610.00 less than paying the full amount in April.
Maturity and five-year extensions
The account matures 15 full financial years after the end of the year it was opened. You can then close it, keep it without deposits for as long as you like, or extend it with deposits in blocks of five years by giving Form-4 within a year of maturity. Without that form, any new deposit is refunded without interest.
During an extension with deposits, withdrawals in each block can add up to 60% of the balance at its start. An account kept without deposits allows one withdrawal of any amount a year, and once it has gone more than a year without deposits it cannot take them again. Two extensions at ₹1,50,000 a year take the example to ₹1,03,08,014.97 after 25 years.
Tax on PPF deposits and interest
As of November 2026, deposits count towards the ₹1,50,000 yearly deduction in section 123 of the Income-tax Act, 2025, which took over from section 80C on 1 April 2026. That limit is shared with life insurance premiums, employee provident fund contributions and the other items in Schedule XV, and it is available only under the old regime, not the default new regime in section 202.
Interest credited each year and the balance paid at maturity are not taxed under either regime, so the calculator's figures need no tax adjustment.