Investing calculators and tools
Free calculators to help you understand your own numbers: how investments could grow, what tax relief is worth, what fees cost and more. Each one uses the official 2026/27 rules, shows its workings and links to a guide that explains the rules in plain English.
- Compound interest calculatorSee how a lump sum and regular investing could grow, and how much fees take.
- Pension tax relief calculatorWhat a pension contribution really costs after tax relief, and how much extra you can claim.
- Platform fee calculatorCompare what investment platforms would cost you a year, based on your balance and how you invest.
- ISA allowance checkerSee how much of your £20,000 ISA allowance is left, days until 5 April and the new cash ISA limit.
- Dividend and Capital Gains Tax calculatorWork out tax on dividends and gains outside an ISA in 2026/27, and what an ISA would save.
- Lifetime ISA calculatorSee what a Lifetime ISA could be worth for a first home or at 60, including the 25% bonus.
- Savings goal calculatorFind out how much to save or invest each month to reach a target by a set date.
- Pension drawdown calculatorSee how long your pension might last if you take a regular income from it.
- Junior ISA calculatorSee what regular payments into a Junior ISA could be worth when your child turns 18.
How our calculators work
Every calculator runs entirely in your browser, so nothing you enter is sent to us or stored. Tax calculations use one set of 2026/27 rates and allowances, taken from GOV.UK and HMRC and tested against HMRC's own worked examples. When the rules change at the start of a new tax year, we update them in one place and every calculator follows. Each page lists the sources it relies on and the date its figures were last checked.
What the results can and can't tell you
The results are illustrations, not predictions or advice. Growth calculators assume a steady return, but real investments rise and fall, sometimes sharply, and you could get back less than you put in. Tax calculators cover the common situations and explain their assumptions, but your own position can depend on things they don't include, such as other income, allowances already used or where you live. If a decision depends on the result, check it with HMRC or a regulated adviser. Free, impartial guidance is available from MoneyHelper.
Guides to go with the tools
Each calculator links to the guide behind it, so you can see why the numbers come out as they do. Browse by topic:
- Investing for BeginnersStart investing in the UK with plain-English guides on how investing works, the risks, what it costs and the tax-free accounts you can use.
- ISAs ExplainedHow ISAs work in the UK: the annual allowance, the different types of ISA, the tax rules and how cash ISAs differ from stocks and shares ISAs.
- Investment Platforms and FeesHow UK investment platforms charge: account fees, dealing charges, fund costs and currency fees, and how small percentages add up over decades.
- Funds, ETFs and Index FundsWhat funds, ETFs, index funds and investment trusts are, how they differ, what they cost and how to read the key numbers on a fund factsheet.
- Pensions and SIPPsHow UK pensions and SIPPs work: tax relief, contribution limits, when you can access your money and how a SIPP differs from a workplace pension.