Savings interest calculator
Work out how much a fixed-term deposit or savings account will pay you, and how much is left after tax.
Savings interest calculator: what it is and how it works
Interest is what a bank pays you for lending it your money. A fixed-term deposit usually pays simple interest: it is calculated on the original amount and paid at maturity. An account that pays interest every month and adds it to the balance uses compound interest, which earns a little more.
Tax rules depend on where you live. If you are tax-resident in Spain, savings income is taxed at 19 % up to €6,000, 21 % up to €50,000, 23 % up to €200,000, 27 % up to €300,000 and 30 % above. Tick the box to apply those rates, or leave it unticked to see gross interest only.
How to use it
- Enter the amount, the annual interest rate and the term in months.
- Choose simple or compound interest and whether to apply Spanish tax.
- Read the gross and net interest and the equivalent AER.
Simple: I = P × rate × months ÷ 12 · Monthly compound: I = P × ((1 + rate ÷ 12)^months − 1)Worked example
A €10,000 deposit at 2.5 % for 12 months earns €250 gross. After Spanish withholding of 19 % (€47.50), you receive €202.50 net.
Frequently asked questions
What is the difference between simple and compound interest?
Simple interest is always calculated on the original deposit. Compound interest is added to the balance at each payment and earns further interest.
Is deposit interest taxed?
In most countries, yes. In Spain it is taxed as savings income from 19 % to 30 %; in the UK a personal savings allowance may apply. Check the rules where you are tax-resident.
Are deposits protected?
In the EU, deposit guarantee schemes cover up to €100,000 per person and bank; in the UK the limit is £85,000.
What is the equivalent AER?
The annual return that matches the interest earned, useful for comparing deposits with different terms.