If I go over £100,000, do I automatically get a bill next year?

Not automatically. The taper increases income tax due for the tax year. Whether PAYE has already collected that amount depends on your tax code and whether HMRC or your employer adjust in-year. Any shortfall can be collected later through a coding change, a P800 calculation, or Self Assessment — or it may already have been collected.

Does my tax code show the personal allowance taper?

A common cumulative code assumes the full personal allowance of £12,570. The taper that withdraws allowance between £100,000 and £125,140 is an annual adjusted-net-income test. A code that still assumes a full allowance can under-collect relative to the year-end position while you are in that band.

A P800 is HMRC’s end-of-year calculation for many PAYE taxpayers who are not on Self Assessment. It compares tax due with tax paid and may show tax owed or a refund. It is one of several ways a shortfall or overpayment can surface — not the only one.

Is childcare reclaim the same as a tax underpayment?

No. Tax-Free Childcare top-ups paid while a parent was over £100,000 of adjusted net income can be reclaimed under the childcare rules. That is separate from income tax collected through PAYE or Self Assessment. See the childcare guide for that cliff.

Does this calculator rebuild my PAYE from my tax code?

No. It applies the statutory personal allowance and the adjusted net income taper for the England, Wales and Northern Ireland rules used here. Your payslip tax code is useful context (and an S prefix signals Scottish income tax, which is not modelled), but the result is not a payslip PAYE rebuild.

2026/27 tax year · England, Wales and Northern Ireland

PAYE codes, the taper, and collecting tax after £100,000

Crossing £100,000 of adjusted net income changes how much income tax is due for the year. It does not, by itself, promise a “next year bill”. What matters is whether PAYE has kept up with the annual taper arithmetic.

Two different clocks

PAYE spreads an assumed personal allowance across the tax year using your tax code. The personal allowance taper is different: it looks at adjusted net income for the whole year and withdraws £1 of allowance for every £2 of income above £100,000, until the allowance is gone at £125,140.

If your code still assumes the full £12,570 allowance while your year-to-date position is already deep into that band, deductions from pay may lag the tax that the annual rules imply. The calculator’s “cost of the taper” figure is that annual extra tax relative to keeping the full allowance — not a forecast of a future invoice.

How shortfalls can be collected

When PAYE has under-collected relative to the year, HMRC has several routes. None of them is guaranteed for every person:

In-year coding. The tax code can change so later months collect more (or less).
P800 / simple assessment. An end-of-year calculation compares tax due with tax paid.
Self Assessment. If you file a return, the balancing payment is the usual place the year is squared up.

Some people never see a separate “payback” because the code already caught up, or because they were never under-collected. The 60% band explanation covers why the extra tax exists; this page covers why timing of collection can differ from a monthly payslip.

What the tax code field is for on this site

If you import a payslip, the tool may read a tax code. An S prefix marks Scottish income tax, which this calculator does not model for income tax. Other codes are shown for sense-checking; they do not rebuild PAYE week by week.

For the £100,000 question, adjusted net income and the statutory taper matter more than the letters on the slip. Build ANI with the adjusted net income guide or the calculator below.

See the taper cost on your figures

Figures update as you type. There is nothing to submit.

Your figures never leave your browser. Payslips are read on your device — not uploaded, not sent to an AI. The calculation runs here too. Nothing you type is stored, logged, or passed to analytics.

Where do you pay income tax?

Scottish income tax rates and bands differ and are not covered by this tool.

England, Wales or Northern IrelandScotland

How do you want to enter your pay?

Drop a payslip to fill year-to-date figures, or enter amounts yourself below. The rest of the calculator appears once you confirm.

Use figures from a payslip

Drop a file below, check the figures, then apply. Or type year-to-date totals by hand.

Drop a payslip or P60 here

or click to choose a file

PDF preferred; a clear photo works too. Read on your device only — never uploaded. One month’s slip is enough to project the year and check the £100,000 line.

Figures are extracted in your browser (text layer or on-device OCR). The file is never sent to us, never passed to an AI provider, and is gone when you close this tab.

Choose how to enter your pay above to see your figures.

Enter figures yourself, or drop a payslip. The rest of the form appears once you confirm.

Childcare reclaim is a different story

Parents sometimes mix up an income-tax underpayment with HMRC reclaiming Tax-Free Childcare top-ups after a year over £100,000. Those are separate systems. Eligibility and reclaim risk for childcare are covered under bonuses and childcare.

What this page does not claim

It does not predict that you will receive a bill next year.
It does not estimate “tax still to pay” from PAYE deducted year-to-date versus annual liability.
It does not replace your Personal Tax Account, P800, or Self Assessment software.

Where money is due or disputed, use HMRC’s published figures and a qualified adviser or accountant. The taper cost shown here is an estimate from the numbers you enter.