Reverse Calculators

Start with the answer you want. Work out what you need.

Take-home → gross salary

Savings goal → monthly saving

Why reverse calculators

Most calculators ask “what's my answer given these inputs?”. Reverse calculators flip that: you start from the answer you want — £3,000/month after tax, £50,000 saved in 5 years — and they tell you the input you need. That's far closer to how people actually plan: target first, work back to what gets you there.

Salary side: gross vs take-home

Each take-home reverse page accounts for income tax bands, National Insurance, and the standard £12,570 personal allowance for 2024/25. They do not assume student loans, pension contributions, or salary sacrifice schemes — those reduce gross-required figures, so treat the numbers as an upper bound. Scottish taxpayers should use the marginal rate entry to adjust.

Savings side: realistic returns

Savings goal pages assume a 4% annual return compounded monthly — roughly the long-run average of a UK Cash ISA in a normal-rate environment. For higher horizons (5+ years) where you'd be in a Stocks & Shares ISA, the actual required monthly contribution is typically 30–40% lower than the figure shown. See the compound interest calculator to model your own rate.