Savings & Deposit Interest Calculator

Calculates what a one-time deposit or a monthly savings plan pays at maturity, with simple or compound interest and tax on the interest. Use it to compare accounts or to see in advance how much you will receive.

How to use

1. Choose "Deposit (one lump sum)" or "Savings plan (monthly)" at the top, and pick the "Currency" if needed.
2. Enter the "Deposit amount" or "Monthly payment", the "Annual interest rate" and the "Term" in months.
3. Choose the "Interest type" and enter the "Tax on interest"; the amount at maturity appears at once.
4. To find how much you need to put in, enter a "Target amount at maturity".

How it works

• Simple interest on a deposit = principal × annual rate × months ÷ 12; on a monthly plan = monthly payment × n(n+1)/2 × annual rate ÷ 12, where n is the number of months. Yearly compounding gives simple interest on leftover months.
• Payments are assumed at the start of each month. Interest and tax are each rounded down to the currency's smallest unit, so a bank's figure can differ slightly.
• The tax rate is 0% by default; enter the rate that applies to your account.

Questions and answers

How much interest does a monthly savings plan at 5% earn?

Paying 1,000 a month for 12 months at 5% simple interest earns 1,000 × 78 × 0.05 ÷ 12 = 325 before tax, less than the 600 that 12,000 earns as a one-year deposit, because later payments earn interest for fewer months.

What is the difference between simple and compound interest?

Compound interest is also paid on interest already earned. 10,000,000 at 4% for 12 months earns 400,000 with simple interest and 407,415 compounded monthly, before tax.

How is the interest after tax calculated?

The tax is the interest × the tax rate. With 325 of interest and a 10% tax, the tax is 32.50 and 292.50 remains.

How much do I need to save each month to get a certain amount?

On "Savings plan (monthly)", enter the "Target amount at maturity" to see the monthly payment needed, after tax.