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Interest Earned Calculator

Enter a balance and a rate to see how much interest you will earn per month, per year, and over the whole period.

How much interest will your savings earn? Enter your balance and the advertised annual rate (AER or APY) to see the interest per month, per year, and over any period, with an optional monthly deposit on top. For example, 100,000 at 4.5% earns 4,500 in the first year, about 368 per month to start. Everything runs in your browser, so your numbers never leave your device.

How to use

  1. Enter your starting balance, for example 100,000. Commas are fine.
  2. Enter the annual rate your account advertises as AER or APY, for example 4.5.
  3. Set the time period in years. It starts at 1 so the first result is a plain one year answer.
  4. Add a monthly deposit if you save regularly, or leave it empty.
  5. Read the interest earned, final balance, first month interest, and first year interest.

Examples

  • 100,000 at 4.5% for 1 year earns 4,500 in interest, about 368 in the first month.
  • 10,000 at 5% for 10 years grows to 16,288.95, which is 6,288.95 of interest.
  • 200,000 at 4% for 1 year earns 8,000, about 655 in the first month.
  • Starting from 0 and saving 100 a month at 5% gives about 1,228 after one year: 1,200 of deposits plus interest.

FAQs

How much interest will I earn per month?
Multiply your balance by the equivalent monthly rate. For an advertised annual rate of 4.5%, the monthly rate is about 0.368%, so 100,000 earns about 368 in the first month. The calculator shows this figure directly, and it rises slightly each month as interest compounds.
What is the difference between AER, APY, and the gross rate?
AER (annual equivalent rate, the UK term) and APY (annual percentage yield, the US term) both describe what a rate delivers after one year of compounding, so they are the number to compare accounts with and the number this calculator expects. A gross or nominal rate ignores compounding, so it understates what you actually receive when interest is paid monthly.
Does the calculator account for compounding?
Yes. The balance grows at the equivalent monthly rate every month, so interest earns interest. Twelve months of that compounding add up to exactly the advertised annual rate, which is what AER and APY mean.
Are my own deposits counted as interest?
No. The interest figure excludes everything you paid in yourself. The final balance includes your deposits, and the note under the results states the deposit total separately so the two are never mixed up.
Does this include tax?
No. Interest is shown gross. Whether tax is due depends on where you live and your allowances, such as the personal savings allowance in the UK, so check the rules that apply to you.
Is my financial information sent anywhere?
No. The calculation runs entirely in your browser. Your balance and rate never leave your device.

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