AER Calculator (Annual Equivalent Rate Returns)

Our AER calculator shows the actual yearly rate of interest you earn on savings, after compounding is taken into account.

1 years
3.75 %

What is AER?

In the UK, AER stands for Annual Equivalent Rate.

AER shows the actual yearly rate of interest you earn on savings, after compounding is taken into account. In other words, it assumes any interest paid during the year is added to your balance and itself earns interest.

It is a very important calculation as it lets you compare savings accounts fairly, even if one pays monthly and another annually

A higher AER always means more interest over a year, assuming the same balance

For example:

If you save £1,000 at 3% AER means you’ll have £1,030 after one year if interest paid annually.

But, if interest is paid monthly, the AER returns would be £1030.42.

Its a AER vs gross rate calculation.

  • Gross rate = the headline interest before compounding
  • AER = the true annual return once compounding is included

You’ll usually see AER used for savings and current account interest, while EAR (Equivalent Annual Rate) is used for overdrafts and borrowing.

How to use the AER calculator to prediction you annual equivalent rate returns)

Understanding how much your savings will grow over time is key to making smart financial decisions. Our AER Calculator helps you compare savings accounts by showing the effective annual return — taking into account how often interest is paid and compounded.

1. Enter Your Initial Deposit

Type in the amount of money you plan to save.
💡 Example: £5,000

  • No commas or symbols needed — just the number.

  • This is the amount you start with before any interest is earned.

2. Choose the Interest Rate

Enter the interest rate offered by the savings product.
💡 Example: 3.5 for 3.5%

  • Use the nominal interest rate (the rate advertised before compounding).

  • Don’t include the % symbol.

3. Select the Compounding Frequency

Pick how often interest is added to your savings:

Option Explanation
Yearly Interest is added once a year
Half-yearly Twice a year
Quarterly Four times per year
Monthly Twelve times per year
Daily Every day

💡 More frequent compounding = slightly more earnings.

4. Choose the Time Period

Select how long you plan to keep the money in the account:

  • Enter the number of years (e.g., 1, 3, 5)

  • You can include up to decimal values if needed (e.g., 0.5 for six months).

5. Click “Calculate”

The calculator will instantly show you:

✅ AER (%) — the true annualised return
✅ Total Value After Interest — how much your savings grow to over your chosen period

No spreadsheets, no manual maths — just clear results.

📘 How to Interpret the Results

Annual Equivalent Rate (AER %)

This tells you:

✔ What your savings effectively earn each year
✔ A fair way to compare different savings accounts

👉 Higher AER = better return (assuming the same risk and access terms).

Total Value After Interest

This shows:

✔ How much your initial deposit will be worth after your selected time period
✔ The impact of compounding interest

🧠 Tips for Using the Calculator

✨ Try different scenarios — see how increasing your deposit or choosing different compounding frequencies affects earnings.

💰 Compare savings accounts — enter different interest rates from real accounts to see which gives you the best return.

📆 Longer timeframes grow faster — the longer you save, the more compounding helps.

📌 Example

Let’s say you put in:

  • £10,000

  • Interest rate: 3%

  • Compounding: Monthly

  • Time: 2 years

The calculator will show you:

📈 AER — e.g., 3.04%
💷 Total Value after 2 years — e.g., £10,619

This means your savings effectively grew at 3.04% per year, and you earned £619 in interest in total.

❓ Common Questions

Q: Can I compare multiple results?
Yes — run the calculator several times with different rates and time periods to compare.

Q: Why does AER differ from the basic interest rate?
Because AER includes compounding — how often interest is added matters.

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