FD Calculator

How the fixed deposit calculator works

A fixed deposit (FD), also known as a term deposit, is a low-risk investment offered by banks and credit unions where you lock in a lump sum for a predetermined period at a guaranteed interest rate. This calculator models both cumulative reinvestment fixed deposits, where interest compounds over the term, and regular payout deposits designed for steady income. All calculations execute directly in your browser without transmitting personal data to any server.

By adjusting the deposit principal, nominal rate, tenure, and compounding frequency, you can inspect exact maturity figures, total accrued interest, and the true effective annual rate (AER). If you are parking short-term cash for unexpected bills, compare your returns against an emergency fund calculator to ensure adequate liquidity. For certificates of deposit issued by American institutions, evaluate penalty structures and APY with our CD calculator.

The fixed deposit compound interest formula

Most commercial banks compound fixed deposit interest on a quarterly basis. For cumulative deposits, the interest earned each quarter is added to the principal balance, causing subsequent interest payments to grow exponentially. The standard compound interest equation determines your final maturity value:

Here, $A$ represents the maturity amount, $P$ is the initial deposit principal, $r$ is the annual nominal interest rate expressed as a decimal, $n$ is the number of compounding intervals per year, and $t$ is the total investment tenure in years.

Total interest accrued over the life of the deposit equals the difference between the maturity amount and the initial principal:

If the tenure is under six months or your agreement specifies simple interest, no compounding takes place, and interest accumulates linearly:

To explore multi-year compounding curves with recurring monthly contributions, visit our dedicated compound interest calculator.

Nominal rate versus effective annual rate (AER)

The nominal interest rate is the headline rate advertised by financial institutions. However, because interest is added to the principal multiple times a year, the actual annual yield you earn is higher. This annualized return is known as the Annual Equivalent Rate (AER) or Annual Percentage Yield (APY).

For example, a fixed deposit with a 7.00% nominal rate compounded quarterly delivers an effective annual rate of approximately 7.19%. You can test varying compounding frequencies and compare equivalent yields across lenders using our effective annual rate calculator.

Cumulative vs non-cumulative payout options

When opening a fixed deposit, depositors generally choose between two payout structures:

• Cumulative (Reinvestment): Interest is retained inside the deposit and compounded periodically until maturity. This structure maximizes total wealth accumulation and is best suited for long-term savings goals.
• Non-Cumulative (Regular Payout): Interest is credited to your savings or checking account at regular intervals (monthly, quarterly, or semi-annually). This option provides a dependable income stream for retirees or conservative investors who need cash flow while keeping principal safe.

When assessing whether a fixed deposit beats equity benchmarks over a multi-year horizon, calculate your portfolio annualized return with the CAGR calculator.

Step-by-step worked example

Suppose an investor deposits $10,000 into a 3-year fixed deposit at an annual rate of 6.00% with quarterly compounding:

1. Identify inputs: Principal $P = \$10{,}000$, rate $r = 0.06$, tenure $t = 3$ years, and compounding periods $n = 4$ per year.
2. Determine total compounding periods: $n \times t = 4 \times 3 = 12$ quarters.
3. Calculate periodic rate: $\frac{r}{n} = \frac{0.06}{4} = 0.015$ (1.50% per quarter).
4. Compute maturity amount: $A = 10{,}000 \times (1 + 0.015)^{12} = 10{,}000 \times 1.195618 = \$11{,}956.18$.
5. Total interest earned equals $\$11{,}956.18 - \$10{,}000 = \$1{,}956.18$.

Frequently asked questions