Free calculatorTax year 2026/27
Savings calculator
Project the future value of regular savings, accounting for interest and inflation.
The calculator
How the savings calculator works
Project the future value of regular savings. Enter your starting balance, monthly contribution, expected interest rate and time horizon, and the calculator estimates what your pot could grow to — optionally adjusted for inflation so you can see the real, spending-power value.
Tax-efficient wrappers such as ISAs and pensions can significantly improve the outcome. We can help you plan savings and investments around your wider tax position.
Tax on savings interest
Interest is taxable, but most people pay nothing on it. There is a personal savings allowance, larger for basic-rate taxpayers than for higher-rate ones and unavailable at the additional rate, and a starting rate for savings that helps people with low earned income. Interest inside an ISA is outside all of this and does not need reporting at all.
Banks report interest to HMRC directly, so where tax is due it is usually collected through a change to your tax code rather than a demand — which is why a code can change without anything else in your life changing.
Compounding and the rate that matters
The frequency of compounding changes the outcome, which is what AER is for: it expresses the return on a common basis so two accounts can be compared honestly. Compare AER rather than headline rates, and check whether a headline rate includes a bonus that expires — a rate that drops after twelve months is a different product from one that does not.
Frequently asked
Should I save in an ISA?+
ISAs let your savings grow free of income and capital gains tax up to the annual limit. Whether an ISA or pension is better depends on your goals and tax position — we can advise.
Do I pay tax on savings interest?+
Often not. A personal savings allowance covers a band of interest tax-free, larger for basic-rate taxpayers, and there is a starting rate for savings for those with low earned income. Above that it is taxable and usually collected through your tax code. Interest inside an ISA is outside all of it.
Why does the bank ask about tax if they already report it?+
They report the interest; they do not deduct the tax. HMRC generally collects any tax due by adjusting your code, which is why a code can change with no other change in your circumstances.
Related
Beyond the tools
An estimate is a starting point, not a plan.
Bring us the number you just worked out and we will tell you what it means for your position — and what to do about it.
Or call 07480 281548