How it works
A Public Provident Fund (PPF) account is a general-purpose, government-backed long-term savings vehicle open to any Indian resident — no age limit, no income proof, and no link to a child's education or marriage goal. You contribute once a year (or in instalments totalling up to ₹1.50 lakh), the government credits interest annually, and the corpus compounds untouched for the full 15-year statutory lock-in. Because PPF sits in the EEE tax basket — exempt at contribution, exempt on interest, exempt at maturity — every rupee of growth shown by this calculator is what you actually receive.
This calculator takes your yearly investment, the prevailing interest rate, and the time period, then projects the maturity value. The default period is 15 years (the mandatory lock-in), but you can model a 5-year extension block if you plan to continue after maturity.
The formula
M = P × [((1 + r)^n − 1) / r] × (1 + r)
Where P is the yearly investment, r is the annual interest rate (as a decimal), and n is the number of years. This is the future value of an annuity due — each deposit is assumed to be made at the start of the financial year, so it earns interest for that full year.
Worked example
You open a PPF account and deposit ₹1,50,000 every year — the maximum eligible for Section 80C tax deduction. The current government-set rate is 7.1% p.a. The mandatory lock-in is 15 years.
| Input | Value |
|---|---|
| Yearly investment (P) | ₹1,50,000 |
| Interest rate (r) | 7.1% = 0.071 |
| Time period (n) | 15 years |
Step-by-step:
- Add 1 to the rate: 1 + 0.071 = 1.071
- Raise to the 15th power: 1.071¹⁵ ≈ 2.6897
- Subtract 1: 2.6897 − 1 = 1.6897
- Divide by r: 1.6897 / 0.071 ≈ 23.7986
- Multiply by (1 + r): 23.7986 × 1.071 ≈ 25.4897
- Multiply by yearly investment: ₹1,50,000 × 25.4897 ≈ ₹38,23,450
Over 15 years you contribute ₹22,50,000 in total. The interest earned is roughly ₹15,73,450, bringing the maturity value to about ₹38.23 lakh — entirely tax-free.
Things to watch
Timing of deposits matters. The formula above assumes you invest at the start of each financial year (ideally before 5th April), so each deposit earns a full year's interest. If you deposit late or in monthly instalments, the effective corpus will be lower than the calculator projects.
The rate is not guaranteed long-term. The government revises PPF rates every quarter based on benchmark government securities. The current 7.1% has held for several quarters, but future rates could change — your actual maturity may differ if the rate shifts mid-way.
The ₹1.5 lakh cap is strict. Deposits above this amount in a financial year earn no interest and provide no additional tax benefit. If you want to invest more, consider supplementary instruments rather than overfunding PPF.
Extensions are optional but powerful. After the 15-year lock-in, you can extend in 5-year blocks while continuing contributions. Each extension compounds the already-grown corpus further.
This calculator gives an estimate based on a fixed rate and yearly contributions. PPF rates are revised quarterly by the government, and actual returns may vary. The figures shown are for planning purposes, not professional financial advice.