How it works
Sukanya Samriddhi Yojana (SSY) is a government small-savings scheme designed specifically for a girl child. An account can be opened any time from her birth until she turns 10, and it matures when she reaches 21. You make yearly deposits for the first 15 years; after that the account simply earns interest on the accumulated balance until maturity. This makes the SSY timeline unique: it is tied to the child's age, not a fixed calendar term.
Two things distinguish SSY from a generic long-term deposit. First, eligibility is restricted — only a girl child under 10 can be the account holder (a parent or legal guardian operates it). Second, the 21-year maturity is measured from her date of birth, so if you open the account late the deposit window and maturity both shift. Both features set SSY apart from PPF, which is open to any Indian resident regardless of age or purpose and matures after a fixed 15-year statutory lock-in.
Deposits qualify for deduction under section 80C (up to ₹1.50 lakh per year), and the interest earned each year plus the final maturity corpus are tax-exempt — the scheme sits in the EEE basket.
The formula
M = D × (((1 + i)^15 − 1) / i) × (1 + i)^6
Here M is the maturity amount, D is the yearly deposit, i is the annual interest rate in decimal (e.g. 0.082 for 8.2%), 15 is the deposit-paying period, and 6 is the gap between the last deposit year and the 21-year maturity. The first part is the future value of an annuity for 15 yearly deposits; the second part compounds that accumulated balance forward for the remaining 6 years with no fresh deposits.
Worked example
A parent opens an SSY account for a daughter aged 3, depositing ₹1,00,000 every year. The interest rate is 8.2% p.a. Deposits are made for 15 years (from age 3 to 17), after which the balance grows untouched until she turns 21 — a 6-year compounding tail. Because the deposit window and maturity are both anchored to the child's age, the timeline runs from age 3 to 21, not a flat 21-year deposit period.
Step-by-step:
- Yearly deposit (D): ₹1,00,000
- Interest rate (i): 8.2% → 0.082
- Deposit period: 15 years
- Compounding tail: 21 − (3 + 15) = 3 years? No — this is a common miscount. Maturity is at age 21, so from age 3 to 21 is 18 years; deposits cover 15 of those, leaving a 3-year tail. Let's recompute with the correct tail of 3 years.
Revised step-by-step with the correct 3-year tail:
- Yearly deposit (D): ₹1,00,000
- Interest rate (i): 0.082
- Deposit period: 15 years
- Tail period: 21 − (3 + 15) = 3 years
- Annuity factor: (((1.082)^15 − 1) / 0.082) = (3.4017 − 1) / 0.082 ≈ 29.289
- Balance after 15 deposits: ₹1,00,000 × 29.289 ≈ ₹29,28,900
- Compounding factor for 3 years: (1.082)^3 ≈ 1.2668
- Maturity amount: ₹29,28,900 × 1.2668 ≈ ₹37,11,600
So the estimated corpus at age 21 is roughly ₹37.1 lakh. Over the 15 deposit years the parent contributes ₹15 lakh; the remaining ₹22.1 lakh is tax-exempt interest.
| Year of deposit | Deposit | Cumulative deposits | Approx. balance at year-end |
|---|---|---|---|
| 1 | ₹1,00,000 | ₹1,00,000 | ₹1,08,200 |
| 5 | ₹1,00,000 | ₹5,00,000 | ₹6,38,000 |
| 10 | ₹1,00,000 | ₹10,00,000 | ₹15,90,000 |
| 15 (last) | ₹1,00,000 | ₹15,00,000 | ₹29,28,900 |
| 18 (maturity) | — | ₹15,00,000 | ₹37,11,600 |
Things to watch
The interest rate is notified by the Ministry of Finance each quarter, so the rate used at the start may not hold for all 21 years. This calculator assumes a flat rate throughout — use it as an estimate, not professional advice. Also remember the deposit window is the first 15 years from account opening, not the first 15 years of the child's life; if you open late, the tail between the last deposit and age 21 shrinks, reducing compounding. The minimum yearly deposit is ₹250 and the maximum is ₹1.50 lakh; deposits above ₹1.50 lakh do not get 80C relief but can still be credited.