Work a savings target both ways: how long it takes at your monthly amount, and the monthly amount that hits your date. Your rate, your inputs.
A savings target is one question asked in two directions, and this calculator answers both at once. Saving £150 a month from a £2,500 start reaches £15,000 in 5 years 11 months at 4% AER; hitting the same target in 5 years flat takes £180.70 a month. Swap in your own target, balance and rate below — the 4% is an example, not a rate anyone is promising you.
One target, two questions: how long at what you can save now, and what a month to hit a date. The rate is an example until you change it.
Saving £150.00 a month reaches £15,000.00 in 5 years 11 months, with £13,150.00 paid in by then.
To get there in 5 years instead, save £180.70 a month — £13,342.00 paid in, with interest taking the balance to £15,000.18.
Deposits are added at the end of each month, after that month's interest. The rate here is yours to set, not a market rate: promotional and bonus rates that expire, withdrawal limits and provider changes are not modelled. A planning estimate, not financial advice.
| Tax/source year | 2026/27 |
|---|---|
| Region | UK-wide: savings interest is taxed on the UK bands and thresholds in every UK nation, including for Scottish taxpayers |
| Account rates | Never assumed. Any interest rate in a savings calculation is an input you set, stated beside the result. |
| Your other income | Wages and pension income decide how much Personal Allowance and starting rate are left for interest, and which Personal Savings Allowance band applies. |
|---|---|
| The interest itself | Interest counts towards the income that sets your band, so a large interest year can shrink the allowance that was meant to cover it. |
| The account's wrapper | The same balance at the same rate is taxed outside an ISA and untouched inside one; the wrapper, not the rate, decides whether the allowances are needed. |
| What is not decided here | PayBreakdown does not decide payroll correctness, lender approval, benefit entitlement or employer compliance, and does not give regulated financial, mortgage, debt, tax, payroll or legal advice. |
|---|
Direction one takes the monthly amount you can actually manage and reports how long the target takes — whole months, rounded up, because you cannot make a fraction of a deposit. Direction two takes the date you want and reports the monthly amount that gets there, rounded up to the penny, so saving exactly that amount lands on or just before the date rather than just after it. Feed one answer into the other and they agree: that round trip is asserted by this calculator's test suite across the whole input range, not assumed.
A target the arithmetic cannot reach says so. If the monthly amount is too small to get there within fifty years, the calculator reports that plainly instead of printing a year no one plans around.
Over short horizons, the monthly amount does nearly all the work and the rate is a rounding error; over long ones, compounding grows into a real contributor. On the example figures above, £13,342 of deposits and £1,658.18 of interest together reach £15,000.18 — the interest share is real but the deposits dominate. The practical reading: pick the monthly amount first, and treat a better rate as a bonus rather than the plan. This calculator never suggests where to find a better rate; comparing accounts is a different job with a different, regulated set of rules.
The same limits as the savings projection calculator, because it is the same arithmetic pointed at a target: promotional rates that expire, withdrawal limits and provider changes are outside the model, the rate is held constant, and interest is reported before any tax. Deposits are added at the end of each month, after that month's interest. If the target is a first home, note that the Lifetime ISA has its own rules and its own government bonus — the Lifetime ISA calculator on the savings hub works both endings through, charge included.
Change any figure above and the result moves with it. A payslip can differ from any calculator because payroll works pay period by pay period, so a tax-code change, a bonus, arrears or a refund can land in one month and not the next. See how each deduction is worked out.
No — with any interest at all, it comes out below the straight division. Dividing the gap by the number of months ignores interest; the calculator counts the interest your growing balance earns along the way, so the required deposit is smaller than the division suggests, and the gap widens with longer terms and higher rates. At a rate of zero the two agree exactly.
The calculator says the target is already met: zero months in the first direction, and nothing a month in the second. It never reports a negative deposit.
Not on this page — a goal is usually a nominal number, like a deposit or a boiler. The savings projection calculator has an optional inflation input that restates an end balance in today's money if you want that view.
Last updated 2026-08-28. Checked by Sean Elsmore. Rates last checked against GOV.UK on 2026-08-07. Estimates are for planning and should be checked against official records where the decision matters.