Compound interest calculator
See how a starting sum plus regular monthly saving grows over time, with interest compounding monthly. This is the single most useful number in personal finance — small, boring, monthly amounts become large ones.
Looking for a home for these savings? Compare current top-rate UK savings accounts. See today's best rates →
Stocks & Shares ISA calculator
Project the tax-free growth of an ISA. You can pay up to £20,000 per tax year into ISAs, and everything it earns — interest, dividends, gains — is free of UK tax.
Ready to open a Stocks & Shares ISA? Compare low-fee UK platforms. Compare ISA providers → Capital at risk.
Pension pot calculator
Estimate your pension pot at retirement and the annual income it could sustainably provide. Include your employer's contribution — it's free money.
Mortgage repayment calculator
Work out your monthly repayment and the total interest you'll hand the bank over the life of the loan. Try shortening the term by five years — the interest saving usually surprises people.
A whole-of-market mortgage broker can often beat the rate your bank offers. Get a free mortgage quote → Your home may be repossessed if you do not keep up repayments.
Savings goal calculator
House deposit, wedding, emergency fund — tell it the target and the deadline, and it tells you the monthly amount that gets you there.
Take-home pay estimator
A quick estimate of your after-tax pay in England, Wales or NI, using 2026/27 income tax bands and Class 1 National Insurance. Excludes student loans, pension salary sacrifice and Scottish tax bands.
Read before you decide
Calculators give you a number. These explain what the number means, using current UK rules.
Cash ISA vs Stocks & Shares ISA
Both are tax-free, but they are not interchangeable. The deciding factor is simpler than most guides suggest.
ISAsISA allowance and rules for 2026/27
£20,000 a year, four account types, and the transfer mistake that quietly wastes your allowance.
SalaryHow your take-home pay is calculated
The 2026/27 bands, why National Insurance behaves differently, and the 60% trap above £100,000.
RetirementHow much pension do I actually need?
Start from the income you want, subtract the State Pension, multiply by 25. Then work backwards.
Quick answers
How much can I put in an ISA this tax year?
The overall ISA allowance is £20,000 per tax year (6 April to 5 April), which you can split across cash ISAs, stocks & shares ISAs, and other ISA types. The allowance doesn't roll over — unused amounts are lost when the tax year ends.
What growth rate should I assume for investments?
Nobody knows future returns. Broad global stock index funds have historically returned somewhere around 5–8% a year over long periods, before inflation — but with big swings along the way, including years of losses. Using a modest figure (5–6%) keeps projections honest.
What is the 4% rule for pensions?
A common rule of thumb: withdrawing about 4% of your pot in the first year of retirement, then adjusting for inflation, has historically given a good chance of the money lasting 30 years. It's a planning guide, not a guarantee.
Is anything on this site financial advice?
No. WealthBot provides calculators and general information only. It is not regulated financial advice and doesn't consider your personal circumstances. For advice, speak to an FCA-authorised adviser.