Savings and Compound Interest Calculator
See how regular savings or investments could grow over time with compound interest. Includes an option to adjust for inflation.
Your savings
Before tax and charges. Not guaranteed.
Up to 60.
Your results
After 20 years
£84,919
You paid in
£49,000
Growth
£35,919
In today's money
£57,148
allowing for 2% inflation
Year by year
| Year | Paid in | Balance | Chart |
|---|---|---|---|
| 1 | £3,400 | £3,507 | |
| 2 | £5,800 | £6,142 | |
| 3 | £8,200 | £8,912 | |
| 4 | £10,600 | £11,824 | |
| 5 | £13,000 | £14,885 | |
| 6 | £15,400 | £18,102 | |
| 7 | £17,800 | £21,484 | |
| 8 | £20,200 | £25,039 | |
| 9 | £22,600 | £28,775 | |
| 10 | £25,000 | £32,703 | |
| 11 | £27,400 | £36,832 | |
| 12 | £29,800 | £41,173 | |
| 13 | £32,200 | £45,735 | |
| 14 | £34,600 | £50,530 | |
| 15 | £37,000 | £55,571 | |
| 16 | £39,400 | £60,870 | |
| 17 | £41,800 | £66,440 | |
| 18 | £44,200 | £72,295 | |
| 19 | £46,600 | £78,450 | |
| 20 | £49,000 | £84,919 |
An illustration, not a forecast. Investments can fall as well as rise and you may get back less than you put in. Tax and charges are not included.
How compound growth works
Compound interest means you earn interest not only on the money you put in, but also on the interest you have already earned. Over short periods the effect is small. Over decades it becomes the biggest part of the result, which is why starting early matters so much for long-term goals such as retirement.
This calculator adds interest every month and assumes you pay in your monthly amount at the end of each month. Enter any lump sum you are starting with, a regular monthly saving, an expected annual rate of growth and the number of years.
Real versus nominal value
Prices rise over time, so £1,000 in 20 years will buy less than £1,000 does today. If you enter an inflation rate, the calculator also shows the result in "today's money" so you can see what your savings might really be worth. The Bank of England aims for inflation of 2% a year, but actual inflation varies.
Important limits
This is an illustration, not a forecast. Cash savings pay interest at rates that change over time. Investments do not grow in a straight line: values can fall as well as rise and you may get back less than you put in. The calculator does not include tax, charges or platform fees, which can reduce returns significantly over time. Check the current ISA allowance and pension rules on GOV.UK before planning.
Common questions
What growth rate should I assume?
It depends on what you are saving in. Cash savings pay the interest rate on your account, which changes. For investments, try several scenarios such as 3%, 5% and 7% rather than relying on one number, and remember that none is guaranteed.
Does the calculator include tax and charges?
No. Tax, fund charges and platform fees would all reduce the result. Using a tax-efficient wrapper such as an ISA or pension can help with tax, but charges still apply.
Why show the result adjusted for inflation?
Because the pounds you have in future will buy less than pounds today. The inflation-adjusted figure shows roughly what the final amount would be worth in today's money.
Related guides
These calculators give estimates based on the figures you enter and the assumptions listed above. They are not financial advice. Your numbers are worked out in your browser and are not sent to us.
This page provides general information only. It is not personalised financial, legal or tax advice, and rules and figures can change. Your situation is unique — please check official sources such as GOV.UK and MoneyHelper, and speak to a qualified, FCA-authorised adviser before making important decisions about your money.