Interest Per Month Calculator

An annual interest rate is quoted for the year, but most loans and savings accounts charge or credit interest monthly. Converting is a simple division — yet the difference between the "annual" headline and what actually happens every month is where most interest confusion lives.

The formula

Monthly rate = annual rate ÷ 12
Monthly interest = principal × monthly rate ÷ 100

Worked example

A loan of ₹50,000 at 12% per annum:

Monthly rate = 12 ÷ 12 = 1%
Monthly interest = 50,000 × 1% = ₹500
Over 12 months: 500 × 12 = ₹6,000 total interest

Simple vs compound

This calculator uses simple interest — the same principal every month. In reality:

• Loans amortize: you pay interest on a shrinking balance, so interest declines each month (see the EMI calculator).
• Fixed deposits compound: interest is added to the principal, so each month earns a little more (see the FD calculator).

For monthly budgeting, simple interest is a great ballpark — for exact repayment, use the amortizing loan calculators.

Converting the other way

Have a monthly rate and want the annual? Multiply by 12: a 1% monthly rate ≈ 12% per annum (nominal) or about 12.68% effective when compounded monthly. Note the compounding side effect: an institution quoting "12% p.a., compounded monthly" on a deposit pays you the effective 12.68%, while the same quote on a loan is the nominal 12% — the two sides of the same phrase are not always the same number.

Where monthly rates hide in plain sight

• Credit cards charge about 3% per month (≈ 36% or more per year). At ₹50,000 rolled over, that is ₹1,500 of interest a month — more than many people's groceries. Card issuers advertise daily or monthly rates because "1.5% daily-periodic" reads smaller than "42% a year".
• Personal loans and gold loans quote monthly in India ("1% per month" is a common lending pitch). On a ₹1 lakh gold loan that is ₹1,000 a month — sneaky cheap, expensive yearly.
• Savings accounts in India pay roughly 2.5–4% a year but credit interest monthly, compounding your savings balance a little every statement.

Practical tips

• Always convert a quoted monthly rate to an annual one before comparing offers: multiply by 12, then ask whether it compounds (and by what period).
• For a budget, monthly simple interest is close enough. For deciding between two loans, use annual effective rates or the EMI calculator — the difference can flip the cheaper loan.
• Annual-rate inputs here accept up to 60%, so the tool also covers credit-card and urgent-loan territory where monthly rates exceed what a yearly 12% suggests.