FD Calculator
Calculate fixed deposit maturity with compound interest. Compare against simple interest.
Formula: A = P(1 + r/n)nt · tenure ≈ 3.00 years
With simple interest (I = P × r × t), you would earn ₹22,500 for a maturity of ₹1,22,500. Compounding adds ₹2,472 extra over the same tenure.
About FD Calculator
The FD / Compound Interest Calculator estimates the maturity value of a fixed deposit (or any lump-sum compound-interest investment) from principal, annual interest rate, tenure and compounding frequency. Tenure combines whole years with months (0–11), converted to a fractional year for the formula. Results show maturity amount, interest earned and principal, with INR currency formatting.
The calculator uses the standard compound formula A = P(1 + r/n)^(n·t), where r is the annual rate as a decimal and n is compounding periods per year: monthly (12), quarterly (4), half-yearly (2) or yearly (1). Banks in India commonly compound FDs quarterly; changing frequency changes maturity even when the advertised annual rate looks identical. A visual breakdown bar shows principal vs interest share of maturity.
A simple-interest comparison panel computes I = P × r × t and the corresponding simple maturity, then highlights how much extra compounding adds over the same tenure. Figures are mathematical estimates for planning. Actual bank payouts may differ due to day-count conventions, TDS, premature-withdrawal penalties or product-specific rate cards (including senior-citizen premiums you must enter yourself as a higher rate).
How FD Calculator works in practice
- 1Enter the principal amount in rupees (defaults illustrate a ₹1,00,000 example).
- 2Enter the annual interest rate as a percentage (for example 7.5).
- 3Set tenure in years and optional months (months capped at 0–11).
- 4Choose compounding: Monthly, Quarterly (default), Half-yearly or Yearly.
- 5Read maturity amount, interest earned and the principal/interest breakdown bars.
- 6Compare against the simple-interest panel to see compounding’s extra rupees for the same tenure.
Jobs this tool is built for
- Compare two bank FD offers that advertise similar rates but different compounding.
- Estimate maturity before parking an emergency fund or bonus in a short-tenure FD.
- Teach compound vs simple interest with concrete INR numbers and the on-page comparison.
- Plan toward a goal amount by trying different tenures and rates until maturity fits the target.
What you can do here
- Compound interest formula A = P(1 + r/n)^(nt)
- Compounding: monthly, quarterly, half-yearly, yearly
- Tenure as years + months (fractional year under the hood)
- Maturity, interest earned and principal summary cards
- Principal vs interest percentage breakdown bars
- Simple-interest comparison with extra-from-compounding callout
- INR formatting via en-IN currency style
Limits and honest caveats
- Does not deduct TDS or apply senior-citizen / special scheme logic automatically — raise or lower the rate yourself to model those products.
- Currency display defaults to INR formatting; the underlying math works for any numeric principal you enter.
- Zero tenure returns principal unchanged (no interest period).
- Bank day-count rules and premature withdrawal can make the credited amount differ from this continuous fractional-year model.
How the result is produced
Maturity uses compound interest. A simple-interest line is shown beside it so you can see what extra the compounding frequency adds. TDS is not deducted.
- 1.Write the annual rate as a decimal. 7.5% is 0.075.
- 2.Pick n, the number of compounding periods in a year: 12, 4, 2, or 1.
- 3.Tenure t is years plus months/12. Two years is t = 2.
- 4.Maturity A = P × (1 + r/n)^(n×t). Interest earned is A − P.
Worked example: ₹1,00,000 at 7.5% for 2 years, quarterly
r = 0.075, n = 4, t = 2, so there are 8 quarters and the quarterly rate is 0.01875. A is about ₹1,16,022, so interest is about ₹16,022. Simple interest on the same deposit is ₹15,000. The extra ₹1,022 is the compounding difference, before any TDS the bank might deduct.
Common questions about FD Calculator
Which compounding frequency should I pick?
Match your bank’s FD sheet. Quarterly compounding is common for Indian retail FDs; monthly or yearly appears on some products. Using the wrong frequency is a frequent source of maturity mismatch.
Why does quarterly beat yearly at the same headline rate?
Interest is credited to principal more often (n = 4 vs n = 1), so later periods earn interest on previously credited interest. The formula A = P(1 + r/n)^(nt) makes that difference visible.
Is TDS included?
No. If tax is deducted at source, your credited amount will be lower than the gross estimate. Adjust expectations or the rate if you want a rough after-TDS sketch.
Can I model recurring deposits (RD)?
Not in this version. It models a single lump-sum principal. For monthly deposits, use a dedicated RD calculator.
How are months converted?
Tenure t = years + months/12. For example 2 years and 6 months becomes t = 2.5 in the compound formula. Months outside 0–11 should be normalised into years for clarity.
This page was written by the ToolSink team to explain how FD Calculator works on this site — it is not syndicated, scraped, or spun from another publisher. How we write tool guides · Site updates · About ToolSink.
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