About the rd calculator
A recurring deposit pays noticeably less than a fixed deposit of the same total, and people are often surprised by that. The reason is simple: in an RD your money arrives a month at a time, so the final instalment earns interest for a single month while only the first earns for the whole term. Half your money is invested for less than half the tenure.
This calculator works instalment by instalment rather than applying a single formula, so you can see exactly what each month contributes. The first instalment in a two-year RD grows for 24 months; the last grows for one. The schedule makes that visible, which is usually the moment the lower return stops feeling like a mistake.
Interest compounds quarterly, matching the Indian bank standard, with each instalment credited for the fraction of a compounding period it was actually invested. Tenures are in months because that is how recurring deposits are sold — the instalment is monthly, so a tenure in odd days has no coherent final payment. Enter 6, 12, 24, 60 or anything between.
There is an optional TDS calculation on the same terms as the fixed deposit tool: editable rate and threshold, because those change and a hard-coded figure quietly goes stale.
If you are weighing an RD against a lump sum you already hold, run the same money through the fixed deposit calculator. The FD will win on returns; the RD wins when you do not have the lump sum yet and the discipline of a monthly transfer is the actual point.