A Recurring Deposit (RD) is a savings scheme offered by banks and post offices. You deposit a fixed amount every month for a set tenure, earning interest compounded quarterly.
M = R ร [(1+i)^n โ 1] / (1 โ (1+i)^(โ1/3))
Where: M = Maturity value R = Monthly deposit i = Quarterly interest rate (annual rate / 4 / 100) n = Number of quarters