Income & Take-home · 2026/27 tax year
Weekly tax set-aside calculator UK 2026/27
Work out exactly how much to set aside from each week or month of self-employed income to cover your Self Assessment bill.
Set aside exactly
£202
every week
Understanding your results
A weekly percentage is a behavioural tool more than a precision tax forecast. If your income swings, the right percentage moves too — revisit the figure quarterly. The goal is that your separate savings account always covers the next January instalment plus July payment on account without touching operating cash.
Effective rates rise with profit, so a flat 20% rule that felt generous at £25,000 of profit becomes dangerously thin at £70,000. When you get a raise in the form of higher day rates or more clients, update the percentage the same week, not after HMRC writes to you.
VAT-registered businesses should segregate VAT collected from income tax savings mentally and physically. Mixing them in one bucket is how people accidentally spend HMRC’s money thinking it is “tax savings.” Two pots — or labels inside one bank’s spaces feature — beats one optimistic heap.
If you use the Budget Payment Plan with HMRC, you are still responsible for reconciling totals. Automated smoothing does not remove the need to understand whether this calculator’s annual estimate matches what your return will show after expenses and pensions.
Finally, celebrate small wins: if you sweep more than needed and January shows a surplus, resist treating it as a windfall until you confirm next July’s payment on account is also covered. Cash buffers are the real product of disciplined set-asides, not the spreadsheet row alone.
Disclaimer: This is a guidance estimate based on the 2026/27 tax year. It is not personal tax advice — consult an accountant or HMRC for your specific circumstances.
About this calculator
The single hardest thing about being self employed is not the work — it is having a tax bill arrive in January for income you spent six months ago. The cure is to put a chunk of every invoice straight into a separate savings account before you ever touch it.
How much? It depends on your profit level. A sole trader making £25,000 has an effective tax and NI rate of around 14% — about £140 of every £1,000. At £50,000, the rate climbs to roughly 24%. At £80,000, you should be holding back nearer 32% to cover the higher-rate band and Class 4 NI.
This calculator estimates your annual tax bill at your current run rate, then divides it by 52 (or 12) to give you a clean weekly or monthly figure. The percentage shown is your effective tax rate — useful as a quick rule of thumb if your income varies.
A common system is to open a separate savings account, transfer the recommended amount the moment a client pays you, and forget about it until January. Set up a standing order if your income is predictable.