Why Two Rates Exist — and Which One Applies to You
When you look at a savings account or a loan offer, you will almost always see a percentage rate advertised. The problem is that banks use different rate labels — APR, AER, gross rate — and they don't always explain which one does what.
APR is the Annual Percentage Rate. It expresses the yearly cost of borrowing, including fees, on products like personal loans, credit cards, and mortgages. If you want to understand debt, APR is your number. Our guide to key borrowing terms covers APR in the context of debt in more detail.
AER is the Annual Equivalent Rate. It's specifically designed for savings. It tells you how much interest your deposited money will earn over a full year, and — crucially — it factors in how often that interest is compounded (added back to your balance so it can earn interest too).
Understanding the difference keeps you from accidentally comparing loan costs to savings returns as if they're the same thing.
APR on savings products: a source of confusion
Occasionally you'll see an APR figure mentioned alongside a savings product, which can be confusing. For savings, AER is the relevant and standardised measure. If a provider only displays APR for a savings account and not AER, ask them directly for the AER before comparing it to other options.
What AER Actually Tells You
Here's why AER matters for savers: interest isn't always added to your account once a year. Some accounts credit interest monthly, some quarterly, some daily. Each time interest is added, your balance grows — and the next round of interest is calculated on that larger balance. This is compounding, and it means the timing of interest payments affects your actual return.
AER converts all of these different schedules into one comparable annual figure. So if Account A pays interest monthly and Account B pays it annually, you can look at both AERs and know exactly which one earns you more — without doing the math yourself.
Our article on how compound interest works explains the mechanics behind this in plain terms with worked examples.
AER
Standard rate label for UK savings accounts
UK regulations require savings providers to display the AER so consumers can compare accounts on a consistent basis.
12x
How often monthly-interest accounts compound annually
An account that credits interest monthly compounds 12 times a year, meaning the AER will be slightly higher than the stated gross rate.
What Banks Don't Always Make Obvious
Banks are required to display the AER on savings products, but that doesn't mean it's always the most prominent figure on the page. Here are a few things to watch for:
- Introductory or bonus rates: Some accounts advertise a high AER that only applies for the first 12 months. After that, the rate can drop significantly. Always check what the rate becomes after any promotional period ends.
- Gross rate vs. AER: The gross rate is simply the interest rate before any compounding is factored in. It will often appear lower than the AER (when interest compounds more than once a year) or equal to it (when interest is paid annually). Focus on AER for comparisons.
- Variable vs. fixed rates: A variable AER can be changed by the bank at any time. A fixed AER is locked in for a specific term. Neither is automatically better — it depends on your needs and what you think rates will do — but you should know which type you're signing up for.
For a broader view of how savings, credit, and debt connect, see Your Financial Starting Point.
Quick comparison tip for savings accounts
When comparing two savings accounts, write down only the AER for each — ignore the gross rate and any headline figures. Then check the terms for access restrictions and whether the rate is fixed or variable. Those three data points will tell you almost everything you need to make a sound comparison.
How to Use This Knowledge When Comparing Accounts
When you're looking at savings options, a simple checklist helps cut through the noise:
- Find the AER for every account you're considering — not the gross rate, not a promotional teaser figure.
- Check whether the rate is variable or fixed and for how long any special rate applies.
- Look at access conditions — notice accounts and fixed-term accounts often offer higher AERs in exchange for limiting when you can withdraw.
- Confirm the minimum deposit required to earn the advertised AER.
None of this requires financial expertise. It just requires knowing which number to look for. The AER is the one standardised figure that lets you make a genuine like-for-like comparison between savings accounts, regardless of how each bank has structured its interest payments.
This article is for general informational and educational purposes only. It is not personalised financial advice. For guidance tailored to your own situation, consider speaking with a qualified financial adviser.
