Post Office RD Calculator: Recurring Deposit Interest

The Post Office RD Calculator estimates the maturity value of a Recurring Deposit account offered by India Post. You enter your monthly deposit amount, the tenure in years, and the applicable interest rate, and it returns the total amount you will receive at maturity, including compounded interest. This is a planning tool, not an official quote, so always confirm the current rate with India Post before investing.

Formula

The maturity value (M) of a recurring deposit is calculated using the formula for compound interest on a series of equal monthly payments:

M = P × [ (1 + i)ⁿ – 1 ] / [ 1 – (1 + i)^–1/3 ]

Where:

• P = monthly deposit amount (in ₹)
• r = annual interest rate (in % per year)
• i = quarterly interest rate = r/400
• n = number of quarters = 4 × tenure in years

This formula assumes quarterly compounding, which is how India Post calculates interest on RD accounts. The exponent –1/3 in the denominator accounts for the fact that each monthly deposit earns interest for a different number of quarters (the first deposit earns for the full tenure, the last for only one month).

Worked Example

Let’s use the default values from the calculator: monthly deposit ₹1,000, tenure 5 years, interest rate 7.5% per year.

1. Quarterly rate i = 7.5 / 400 = 0.01875
2. Number of quarters n = 4 × 5 = 20
3. Compute (1 + i)ⁿ = (1.01875)²⁰ ≈ 1.449948
4. Compute (1 + i)^–1/3 = (1.01875)^{–0.3333} ≈ 0.993826
5. Numerator = 1.449948 – 1 = 0.449948
6. Denominator = 1 – 0.993826 = 0.006174
7. Fraction = 0.449948 / 0.006174 ≈ 72.878
8. Maturity value = 1000 × 72.878 = ₹72,878 (rounded to nearest rupee)

The calculator gives ₹72,878.00, matching our manual calculation. The interest earned is ₹72,878 – (1000 × 12 × 5) = ₹72,878 – ₹60,000 = ₹12,878.

How India Post RD Works

India Post’s Recurring Deposit (RD) is a small savings scheme where you deposit a fixed amount every month for a chosen tenure (usually 1 to 10 years). The key features:

• Minimum monthly deposit: ₹100 (no upper limit)
• Tenure options: 1, 2, 3, 4, 5, or 10 years (5 years is most common)
• Interest is compounded quarterly, credited at maturity
• Rate is set by the Government of India and revised quarterly
• Premature closure allowed after 1 year, with a small penalty
• Deposits qualify for tax deduction under Section 80C (up to limits)

The interest rate is not fixed for the entire tenure – it is reviewed every quarter. If rates change, the new rate applies to future deposits, but existing deposits continue at the rate that was applicable at the time of opening (for the full tenure, as per current rules).

How to Use the Calculator

Using the calculator is straightforward:

1. Enter your monthly deposit amount (e.g., 2000)
2. Select the tenure in years (1 to 10)
3. Enter the current interest rate (check the India Post website or your local post office)
4. Click calculate to see the maturity value and total interest

The result shows the maturity value as the headline number, and the interest earned below it. Use this to compare with other investment options or to set a savings target.

Common Mistakes and Misconceptions

Many people make errors when estimating RD returns. Here are the most common:

• Using annual compounding instead of quarterly: The formula must use quarterly compounding; using annual will give a slightly lower result.
• Ignoring the fractional exponent: The –1/3 term is essential because deposits are monthly, not quarterly. Omitting it overestimates the maturity value.
• Assuming the rate stays constant: The rate can change, but for a given RD account, the rate at opening is locked for the tenure. Always use the current rate for new accounts.
• Rounding too early: Keep full precision until the final step; rounding intermediate values can change the result by a few rupees.

A common misconception is that the interest is compounded monthly. It is actually quarterly, which is why the formula uses r/400 and 4n.

Limitations of the Calculator

This calculator gives an estimate based on the inputs you provide. Real-world results may differ because:

• Interest rates are revised quarterly; the rate you enter may not be the rate for the entire tenure if you open the account later.
• India Post may impose a penalty for missed deposits (usually ₹1 per ₹100 defaulted).
• Tax deductions and TDS are not considered here.
• The calculator assumes all 12 monthly deposits are made on time each year.

For exact figures, always use the official India Post RD calculator on their website or consult your post office.

Frequently Asked Questions

What is the current interest rate for Post Office RD?

Interest rates are revised quarterly by the Government of India. As of the last quarter, the rate is around 7.5% per annum (compounded quarterly). Check the India Post website or your nearest post office for the latest rate, as it can change.

Can I close my Post Office RD before maturity?

Yes, you can close the account prematurely after one year. A penalty of 1% of the maturity amount is deducted, and interest is paid at the applicable savings account rate (currently 4% per annum) for the completed quarters.

Is the interest on Post Office RD taxable?

Interest earned is taxable as per your income tax slab. However, the deposit amount (up to ₹1.5 lakh per year) qualifies for deduction under Section 80C. TDS is not deducted on RD interest, but you must declare it in your tax return.

What happens if I miss a monthly deposit?

If you miss a deposit, you can pay it later with a default fee of ₹1 per ₹100 of the missed amount. The account may be closed if you miss four consecutive deposits, and you will receive the maturity value with applicable penalties.

Can I open multiple RD accounts?

Yes, you can open multiple RD accounts, but the total deposit across all accounts cannot exceed ₹1.5 lakh per year to qualify for the 80C deduction. There is no upper limit on the monthly deposit per account.

How is the maturity amount paid?

The maturity amount is paid by cheque or credited directly to your linked savings account. You need to submit the passbook and a withdrawal form at your post office to receive the final amount.

Related

• How Much Is Decomposed Granite? Cost Guide
• Decomposed Granite Weight: Per Cubic Yard & Ton
• Decomposed Granite Calculator: How Much Do You Need?

in p | Monthly deposit | ₹ | 1000 | 0 | 1000000
in n | Tenure | years | 5 | 1 | 10
in r | Interest rate | % per year | 7.5 | 0 | 15
out m | Maturity value | ₹ | p * ((pow(1 + r/400, 4*n) - 1) / (1 - pow(1 + r/400, -1/3))) | 2
out i | Interest earned | ₹ | (p * ((pow(1 + r/400, 4*n) - 1) / (1 - pow(1 + r/400, -1/3)))) - (p * 12 * n) | 2