Banks compound RD interest quarterly. Add an inflation rate to see whether your savings are growing in real terms.
How RD maturity is calculated
Maturity = Σ R × (1 + r ÷ 4)^(months remaining ÷ 3)
- R
- Monthly deposit
- r
- Annual interest rate
- ÷ 4
- Quarterly compounding used by most banks
- Σ
- Sum over every monthly instalment
Each instalment earns interest only for the months it stays in the account, so the first deposit earns the most and the last earns the least.
RD interest is taxable at your slab rate, and banks deduct TDS when total interest crosses the yearly threshold. Missing instalments can attract a small penalty.
RD vs SIP vs FD
All three suit different needs.
- RD: fixed, guaranteed returns on monthly savings. Good for short-term goals.
- FD: fixed returns on a lump sum you already have.
- SIP: market-linked, potentially higher returns on monthly savings for long-term goals.