PPF Calculator

What is PPF?

Public Provident Fund is the longest-running, most reliable savings scheme that the Indian government runs. It was introduced under the PPF Act of 1968 and has stayed mostly unchanged since, except for the interest rate (which is reset every quarter) and the annual contribution ceiling (raised from ₹70,000 to ₹1 lakh in 2011, then ₹1.5 lakh in 2014). Any resident Indian, salaried or self-employed, can open a PPF account at any post office or authorized bank branch with PAN, Aadhaar and a small initial deposit.

The defining features are a 15-year lock-in, annual compounding at a government-set rate, and an unbeatable tax treatment. PPF qualifies as EEE under Section 10(11) of the Income Tax Act. Contributions get a deduction under Section 80C (₹1.5 lakh cap, old regime only). The interest credited every year is fully tax-free. The maturity proceeds are fully tax-free. There is no other Indian product that delivers all three exemptions at the same time. EPF is EEE but only up to ₹2.5 lakh annual contribution. NPS gets you tax-free corpus only on the 40% withdrawn at exit; the remaining 60% gets taxed as annuity income.

How PPF interest is calculated

Interest each month is computed on the lowest balance held between the 5th of the month and the last day of the month. That sum is credited as a single annual amount on 31 March. The lowest-balance rule is the reason almost every PPF advisor tells you to deposit your entire year's contribution before 5 April. A ₹1.5 lakh deposit on 4 April earns interest for the full 12 months; the same deposit on 6 April earns interest for only 11 months, which costs you roughly ₹950 at the current 7.1% rate.

For long-horizon projections, the lowest-balance rule reduces to a simple annual compounding formula assuming contributions land at the start of each year:

Maturity = A × [((1+r)^n − 1) / r] × (1+r)

Where A is the yearly contribution, r is the annual rate as a decimal, and n is the tenure in years. The trailing (1+r) factor is what makes this an annuity-due rather than an ordinary annuity, reflecting the start-of-year deposit assumption.

Worked example

You contribute the maximum ₹1,50,000 every year for the standard 15-year tenure at the current 7.1% rate.

The factor (1.071)^15 works out to about 2.8043. Plug it in: 150000 × ((2.8043 − 1) / 0.071) × 1.071. That comes to ₹40,82,500 approximately. Of this, ₹22.5 lakh is your contribution and ₹18.32 lakh is tax-free interest. The ratio of interest to contribution crosses 1 between year 9 and year 11 depending on the exact rate path, which is when compounding visibly takes over.

Now extend by one 5-year block to a 20-year tenure with continued ₹1.5 lakh contributions. Maturity rises to about ₹66.6 lakh against ₹30 lakh contributed, with ₹36.6 lakh tax-free interest. The marginal year-16 onwards contributions grow at a much better rate than fresh contributions to a new PPF account would, which is why most PPF experts treat the 15-year mark as a milestone, not a finish line.

Common mistakes to avoid

The biggest mistake is depositing late in the financial year. Money sitting in a savings account till March earning 2.5%, then transferred to PPF on 31 March, loses 11 months of 7.1% compounding. For a ₹1.5 lakh contribution that is roughly ₹950 every year, and over a 15-year tenure with reinvestment that compounds into ₹25,000 of lost maturity value. Set up an auto-transfer on 1 April or pay before 4 April manually.

Skipping a year by accident is the second most common error. The minimum deposit is just ₹500 per financial year, and missing this turns the account "inactive". Reactivation requires a ₹50 penalty plus paying the ₹500 minimum for each skipped year. Even on tight cash flow, depositing the bare minimum keeps the account alive.

Don't double-up PPF for both Section 80C and emergency liquidity. The 15-year lock-in is real. Partial withdrawal is allowed only from the 7th year onwards, and even then is capped at half the 4th-year-prior balance. PPF is the wrong place for money you might need in 5 years. Use a short-duration debt mutual fund or a 3-year tax-saver FD for the medium horizon.

Final trap, comparing PPF to equity returns without adjusting for risk. PPF gives 7.1% guaranteed and tax-free, which is equivalent to about 10.3% pre-tax in the 30% slab. Equity mutual funds have averaged 11-13% pre-tax over 15-year windows but with real drawdowns of 30-50% along the way; the SIP calculator shows what a parallel ₹1.5 lakh per year commitment to an equity fund looks like over the same horizon. The right comparison for the guaranteed portion of your savings is PPF vs other debt: FD, EPF, NSC, RBI Floating Rate Bonds, government securities. PPF wins or ties on every metric for retail amounts under ₹1.5 lakh per year.