APY calculator (UK)
Convert a quoted interest rate into the effective annual yield, and see what compounding adds.
APY calculator
Assumes the rate holds for the full period and interest is left in the account. Most savings rates are variable. In the United Kingdom this figure is usually quoted as AER — annual equivalent rate.
Estimate only. This result is produced from the figures you entered and the assumptions listed on this page. It is not financial advice, not a quotation and not an offer, and no provider is bound by it. Check current terms with the provider before acting. Nothing you type here is sent anywhere — the calculation runs entirely in your browser.
How this is worked out
APY = (1 + r ÷ n)^n − 1What this assumes
A calculator is only as good as what it leaves out. These are the assumptions built into the result above.
- The rate stays the same for a full year. Most savings rates are variable.
- Interest is left in the account to compound rather than withdrawn.
- Tax is not deducted.
Educational information only. This page explains how something works in the United Kingdom. It is not financial advice and does not take account of your circumstances. Rates, fees and eligibility change without notice — check the provider’s own terms before you act.
For free, impartial guidance, see MoneyHelper. To complain about a firm, contact the Financial Ombudsman Service.
Guides that go with this tool
What Is AER on a Savings Account?
AER shows what a savings account returns over a year once interest compounds. It exists so accounts paying monthly and annually can be compared honestly.
UK Savings Accounts: Which Type Fits Your Money
Easy access, notice, fixed-rate bonds, cash ISAs and regular savers — what each is for, and how to decide between them.
APR vs AER: What's the Difference?
APR is what borrowing costs. AER is what saving earns. Both are annual percentages, both are regulated, and they measure opposite things.