Estimate recurring deposit growth
- Enter the same amount for each monthly deposit.
- Enter a fixed annual nominal rate and the number of monthly deposits.
- Calculate and download monthly checkpoints.
Timing and formula
Each deposit arrives at the beginning of a month. Maturity is at the end of the final month, so the first deposit grows for n months and the last for one month. Quarterly nominal growth is 1 + annual rate ÷ 400. Equivalent equal-month growth i = (1 + annual rate ÷ 400)1/3 − 1.
Maturity = P × [(1 + i)n − 1] ÷ i × (1 + i). At 0% rate, maturity is P × n. P is each monthly deposit; total deposits are P × n. Interest is maturity minus total deposits.
Example: twelve 100-unit monthly deposits at 0% produce 1,200. At a nominal 12% quarterly-compounded rate, one 100-unit deposit over one equal month grows to about 100.99.
HDFC Bank’s RD explanation describes quarterly compounding. Its RD product information specifies Actual/Actual quarterly compounding. This tool deliberately uses equal months and fractional-quarter growth, so actual-date results can differ.
Assumptions and limits
Fixed monthly deposits, fixed nominal rate, no missed or late instalments and all interest retained. No taxes/TDS, fees, penalties, premature closure, special rates, holidays or actual day counts. The fractional-quarter model is a mathematical estimate; it does not apply a particular bank’s partial-quarter rules. Monthly deposit 0.01–1 billion units; rate 0–100%; term 1–600 whole months. Bounds are numeric limits, not product eligibility.
This is an estimate, not advice, a deposit quote or guarantee. The CSV gives monthly cumulative deposits, projected value and interest using six decimals, with scientific notation for tiny nonzero amounts, plus the inputs and timing assumptions. The checkpoints show modeled growth, not actual bank postings. Display uses currency precision.
Privacy
Inputs and projections stay in browser memory without uploads or saved financial values. Editing clears stale output; Reset restores illustrative defaults. Undo restores the previous inputs, currency search and projection after Reset or a without-interest comparison, including after recalculation. Editing a field discards that recovery snapshot.
How is this different from SIP?
This RD model uses a nominal rate compounded quarterly and beginning-of-month deposits. The SIP calculator instead takes an effective annual investment return and lets you choose contribution timing.
Why does my bank quote differ?
Actual deposit dates, day counts, quarter boundaries, taxes, rounding and missed instalments can change the result. Use the bank’s agreement and quote for the actual amount.