Savings Calculator
Use this for cash savings goals. Enter what you already have, what you can add each month and the target you want to reach.
Enter your savings figures
This calculator assumes monthly saving and monthly compounding. Interest rates can change, and tax may affect the return you actually keep.
Your savings estimate
Your result will update as you change the figures.
Save or share this scenario
The page URL captures everything you've entered above. Copy it to come back later or share these inputs with someone.
Year-by-year savings
See how the estimate changes over time.
| Year | Total paid in | Estimated interest | Estimated savings |
|---|
Understanding the savings calculator inputs
The calculator above uses four straightforward inputs. Small changes to any of them can move the answer significantly over long periods.
Starting balance
What you already have in the account today. Leave it at zero if you're starting fresh.
Monthly deposit
What you'll add each month. Setting up a standing order on payday makes this much easier to stick to.
Interest rate (AER)
The Annual Equivalent Rate the account pays. UK accounts must advertise an AER so you can compare them fairly.
Time period
How long you'll save for. The maths is most interesting beyond 3-5 years, when compounding starts to add up.
How quickly could your savings grow?
These examples assume a 4% AER on a zero starting balance with monthly contributions. They're illustrative; real-world rates change.
| Monthly saving | Balance after 5 years | Balance after 10 years | Balance after 20 years |
|---|---|---|---|
| £100/month | £6,652 | £14,774 | £36,800 |
| £250/month | £16,629 | £36,936 | £91,999 |
| £500/month | £33,258 | £73,872 | £183,998 |
| £1,000/month | £66,516 | £147,745 | £367,997 |
These figures don't account for tax on interest, inflation, or changes in the interest rate. Use them as a feel for the shape of the maths, not a forecast.
What interest rate should I use?
UK savings rates depend on the type of account and the Bank of England base rate. The three broad categories below give a useful frame.
Easy-access accounts
Money in and out whenever you want, but the rate is variable. Providers can drop the rate after you open the account, so it's worth reviewing yearly.
Notice accounts
You give 30, 60 or 90 days' notice before withdrawing. The trade-off is usually a slightly higher rate than easy-access.
Fixed-rate bonds
You lock the money away for 1-5 years in exchange for a guaranteed rate. Useful for money you definitely won't need before the term ends.
Always compare the AER, not the gross rate, and check whether interest is paid monthly or annually; monthly interest compounds slightly faster.
What about tax on UK savings interest?
The calculator above shows gross interest. In reality, UK savers may pay tax on some of it depending on their income.
The Personal Savings Allowance lets basic-rate taxpayers earn £1,000 of interest a year tax-free. Higher-rate taxpayers get £500. Additional-rate taxpayers don't get the allowance at all. Beyond that, interest is taxed at your marginal rate.
A Cash ISA is the standard way to shelter savings interest from tax in the UK. The annual ISA allowance covers cash and investments combined. Any interest earned inside a Cash ISA is tax-free regardless of your income, which makes it especially valuable as your balance grows or rates rise.
Common savings calculator mistakes
The calculator is only as accurate as the assumptions you feed it. Watch for these.
Using a stale rate
UK savings rates move with the base rate. The 5% you opened the account at last year may be 3.5% now.
Forgetting tax
If you breach the Personal Savings Allowance, the effective rate you keep is lower than the headline AER.
Ignoring inflation
If inflation runs higher than your interest rate, your money loses purchasing power even though the number goes up.
Treating cash like investing
Cash savings rarely keep pace with long-term stock market returns. For goals more than 5-10 years away, mixing in investments may help.
Not using an ISA wrapper
If you're earning meaningful interest, holding it inside a Cash ISA can be the difference between keeping it and giving some back in tax.
Setting and forgetting
Easy-access rates often drop after a year. A 10-minute rate review every spring usually pays for itself.
Savings Calculator FAQs
Quick answers to the questions people most often ask about the calculator and how to use it.
How is this different from an investment calculator?
A savings calculator assumes a fixed interest rate on cash. An investment calculator models money in the market, where returns vary and your capital can go down as well as up.
What interest rate should I enter?
Use the AER advertised by the account you have, or are comparing. Don't enter the gross rate; AER reflects compounding and is the apples-to-apples figure.
Does this account for tax on interest?
No. Results are gross. Check the Personal Savings Allowance and consider a Cash ISA if your interest is likely to be taxable.
Should I save monthly or in lump sums?
Both work; the calculator handles both via the starting balance and monthly deposit fields. Regular monthly deposits suit most people because they fit naturally with monthly income.
Tax and official tools
Interest is shown before tax. Most basic and higher-rate taxpayers have a Personal Savings Allowance, and interest above it is taxable; interest inside a cash ISA is tax-free.
Sources used for this calculator:
Sources, assumptions and review date
Last reviewed: 19 May 2026. The calculator shows gross savings growth before tax and inflation.
- Personal Savings Allowance: currently £1,000 for basic-rate taxpayers, £500 for higher-rate taxpayers and £0 for additional-rate taxpayers.
- ISA allowance: £20,000 for the 2026/27 tax year across ISA types.
- Savings interest tax rates are expected to change from April 2027, so tax-sensitive savings content should be reviewed before the 2027/28 tax year.
Primary sources: GOV.UK tax-free savings interest and GOV.UK ISA rules.