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.
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.
Platform fees come straight out of your return every year. Before you open an account, compare the annual platform charge, dealing fees and fund charges on each provider's own costs page — on a £20,000 pot, 0.45% is £90 a year. ISA allowance rules →
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.
Coming to the end of a fixed rate? Remortgaging is where most people save the most, and some services pay cashback on completion. Check remortgage options → Your home may be repossessed if you do not keep up repayments. Advertising — we may earn a commission.
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.
Bookmark this — the numbers will change
Tax bands reset every April, salaries change, and rates move. These are calculations you will want to run more than once. Press Ctrl + D — or ⌘ + D on a Mac.
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.
ISAsLifetime ISA: bonus, penalty, and what's changing
Up to £1,000 a year free — and a 25% exit charge that can take more than the bonus. Plus the planned 2028 replacement.
SavingsHow big should your emergency fund be?
Size it against essential spending, not salary. Where to keep it, and the point at which you should stop adding.
PropertyOverpay the mortgage or invest?
One is guaranteed and tax-free, the other is bigger on average. How to compare them, and what comes before both.
MortgagesHow much can I borrow for a mortgage?
The 4–4.5× income rule, what the affordability check really tests, and four things that raise your number.
StudentsStudent loan repayments explained
2026/27 thresholds for Plans 1, 2, 4 and 5 — and why overpaying is usually the wrong move.
GraduatesYour first salary: what to do with it
The order that works — pension first, then a buffer, then debt. Plus the lifestyle creep trap.
RetirementThe 25% tax-free pension lump sum
How the taxable 75% works, the emergency tax shock on your first withdrawal, and the MPAA trap.
RetirementThe State Pension explained
£241.30 a week, 35 qualifying years, and why filling gaps can be excellent value.
StudentsPlan 3: the student loan nobody can find
It isn't missing — Plan 3 is the Postgraduate Loan. Lowest threshold of any plan, and it stacks on top of your undergraduate one.
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.