Savings Interest Calculator

See exactly how much interest your savings could earn — with or without monthly contributions. Updated with live UK rates.

Your Savings Details

Annual rate4.50% AER
0.1%10%
£
£0£1,000,000
£
£0£5,000/mo
yrs
1 yr30 yrs

Your Projected Returns

4.50% AER · 5 years
Final Balance
£25,947.07
after 5 years
Interest Earned
£3,947.07
+17.9%
total return
Total Deposited
£22,000.00
Monthly Gain
£65.78

Balance Growth Over Time

How your pot builds up, month by month

StartingContributionsInterest

AER vs Gross Interest — What's the Difference?

When comparing savings accounts, you'll see two figures quoted: AER and gross rate. Understanding the difference helps you choose the account that actually pays more.

AER (Annual Equivalent Rate) is the standardised rate that accounts for compounding. It shows what you'd earn if interest were paid and compounded once per year, regardless of how often the account actually pays it. This makes it the fairest way to compare accounts side by side.

Gross rate is the rate before compounding is applied. If an account pays monthly, the gross monthly rate is slightly lower than AER/12 — because each month's interest is calculated on a growing balance.

Quick example

A £10,000 deposit at 4% AER with monthly compounding earns £407.74 after one year. At 4% gross (simple interest, annual), it earns exactly £400. The AER account pays more, even though the headline numbers look similar.

Lump Sum vs Monthly Contributions

Two common savings strategies produce different outcomes even at the same interest rate.

Lump sum

  • ✓ Full amount earns interest from day one
  • ✓ Compound interest works on the largest possible base
  • ✓ Best if you already have savings to deploy
  • ✗ Requires a large initial deposit

Monthly contributions

  • ✓ Builds savings from regular income
  • ✓ No large upfront amount required
  • ✓ Enforces a consistent saving habit
  • ✗ Each contribution earns interest for less time

Try the calculator above with just a starting balance versus with a monthly contribution added — you'll often find that consistent monthly contributions significantly outperform a one-off deposit over a longer period.

How to Maximise Your Savings Interest in the UK

1

Use your ISA allowance first

Each tax year you can save up to £20,000 in a Cash ISA and pay zero tax on the interest — regardless of how much you earn. Cash ISA rates have improved substantially since 2023 and now rival many standard savings accounts.

2

Consider fixed-rate bonds for money you won't need

Fixed-rate savings accounts typically offer higher rates in exchange for locking your money away for 1–5 years. If rates are high and expected to fall, locking in now can protect your returns.

3

Don't ignore your Personal Savings Allowance

Basic-rate taxpayers can earn up to £1,000 in savings interest tax-free each year. Higher-rate taxpayers get £500. If your interest would exceed this, prioritise ISAs or check our savings tax calculator.

4

Keep comparing — rates change frequently

Savings rates shift with the Bank of England base rate and competition between providers. The best rate today may not be the best rate in six months. DepositScout's comparison table is updated in real time so you can always see where the best rates are.

Common Questions

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