INCOME TAX · 2026/27

The Number HMRC Uses That You Have Never Heard Of

Adjusted Net Income determines your Personal Allowance, your Child Benefit, and your free childcare. It is also the figure you can actually control.

10 min read · Updated June 2026

Most people know roughly what they earn. Most people have a vague sense of what they take home. And most people assume that HMRC, when deciding how much tax to charge them, is working from one of those two numbers.

It is not.

HMRC uses a different figure entirely — one that does not appear on your payslip, is not shown on your P60, and has a name that most people encounter for the first time when something goes wrong. It is called Adjusted Net Income. And understanding it is one of the most practically useful things a higher earner in the UK can do.

Not because it changes how much you earn. But because, unlike your gross salary, it is a number you can influence. And the difference between your current ANI and a more favourable one can be worth thousands of pounds a year.

Your gross salary is fixed by your employer. Your Adjusted Net Income is partly set by your choices.

What Adjusted Net Income Actually Is

ANI is not complicated to understand, even if the name suggests otherwise. Start with your total income from all sources: employment salary, bonus, dividends, savings interest, rental income, taxable benefits in kind. That is your gross income.

From that total, HMRC deducts certain things. The most significant are:

Pension contributions. If your pension contribution is made through salary sacrifice or a Net Pay Arrangement, it has already reduced your gross pay before PAYE runs — so it has already reduced the starting number. If your contribution is made through Relief at Source — where you pay 80% and the provider claims 20% from HMRC — the full gross amount (100%, not the 80% you physically paid) is deducted from your ANI separately. A £800 RAS contribution reduces your ANI by £1,000.

Gift Aid donations. When you donate to charity under Gift Aid, the charity claims back 20% basic rate tax from HMRC. Your ANI is reduced by the grossed-up value of your donation — your cash amount divided by 0.8. A £800 cash donation reduces your ANI by £1,000.

Cycle to Work and other salary sacrifice deductions. Any genuine salary sacrifice — where your contractual salary has been reduced — flows through into a lower starting number for the ANI calculation.

What remains after these deductions is your Adjusted Net Income. It is this figure that HMRC uses to apply several of the most consequential rules in the UK tax system.

Four Things ANI Controls

The reason ANI matters is not theoretical. It determines four separate things that have direct, significant financial consequences for millions of UK taxpayers.

Your Personal Allowance.

Everyone in the UK is entitled to a Personal Allowance — income on which they pay no tax at all. In 2026/27 it is £12,570. Above £100,000 ANI, HMRC begins withdrawing it: £1 of allowance lost for every £2 of ANI above the threshold. At £125,140, it is gone entirely. This creates an effective marginal rate of 60% in the taper zone. Reduce your ANI below £100,000 and the full allowance is restored.

The Child Benefit High Income Charge.

Child Benefit is paid to families with children regardless of income. But if any individual in the household has ANI above £60,000, a tax charge begins clawing it back — 1% of the benefit for every £200 of ANI above £60,000. At £80,000 ANI, it is entirely repaid. This means that someone with two children earning £80,000 is effectively receiving no Child Benefit, despite claiming it and paying it back through self-assessment. Reducing ANI below £60,000 eliminates the charge.

Free childcare eligibility in England.

The 30-hour free childcare entitlement for three and four-year-olds requires both parents to have ANI below £100,000. There is no taper. One parent with ANI of £100,001 removes the additional 15 hours from the household entirely — a benefit worth between £6,000 and £8,000 per year depending on location and provider. Reducing that parent’s ANI below £100,000 restores eligibility in full.

The Self Assessment obligation.

Above £100,000 ANI, you are required to file a Self Assessment tax return each year, even if all your income is collected through PAYE. This is where you also formally claim any additional pension relief or Gift Aid relief beyond the basic rate — so the return, for many people, is not just a compliance obligation but an opportunity to reclaim money owed.

The three thresholds that matter:

£60,000 ANI: Child Benefit High Income Charge begins

£80,000 ANI: Child Benefit fully clawed back

£100,000 ANI: Personal Allowance taper begins. Free childcare eligibility lost. Self Assessment required.

£125,140 ANI: Personal Allowance fully gone. 60% effective rate throughout the taper zone.

Why the Distinction Between Gross Salary and ANI Matters

Here is the practical implication of all of this: your gross salary is set by your employer. You cannot reduce it by deciding to. But your ANI is partly within your control — because pension contributions, Gift Aid donations, and salary sacrifice deductions all reduce it.

Consider two people with identical gross salaries of £105,000.

Person A has made no pension contributions beyond their employer’s minimum, makes no Gift Aid donations, and has no salary sacrifice arrangements. Their ANI is £105,000. Their Personal Allowance is £10,070 — £2,500 of allowance has been tapered away. They pay approximately £2,000 more in Income Tax than someone earning just below £100,000.

Person B has increased their salary sacrifice pension contribution by £5,000 per year. Their ANI is £100,000. Their Personal Allowance is fully restored to £12,570. That £5,000 pension contribution — which is growing in their pension pot, invested in their name — has cost them £3,000 in reduced take-home pay. HMRC provided the other £2,000 through the restored allowance, on top of the standard 40% pension tax relief.

Same employer. Same gross salary. Different ANI. Different tax bill. The difference is choices.

Two people can earn the same salary and pay significantly different amounts of tax. ANI is often the reason.

The Gift Aid Angle

Pension contributions attract most of the attention in ANI conversations, because they are large and the saving is substantial. But Gift Aid is worth considering separately, particularly for those who give to charity regularly.

When you donate under Gift Aid, the charity receives the grossed-up amount — your cash donation plus 20% claimed from HMRC. Your ANI falls by the grossed-up total, not just the cash you paid.

For someone with ANI of £104,000, a £3,200 cash donation under Gift Aid reduces ANI by £4,000. ANI falls to £100,000. Personal Allowance is fully restored. Tax saving from the restored allowance: £2,000. The charity received £4,000 from a £3,200 donation. The donor saved £2,000 in additional Income Tax. The government effectively contributed £2,800 out of the £4,000 received by the charity.

This is not a tax avoidance scheme. It is the Gift Aid system functioning exactly as designed — with the taper zone amplifying the benefit for those who happen to be in it. Whether you would have made the donation anyway is the relevant question. If you give regularly, structuring those gifts as Gift Aid while in the taper zone costs nothing and benefits the charity significantly more.

The Relief at Source Detail

One technical point that catches people out, and that many calculators get wrong.

For pensions using Relief at Source — personal pensions, most SIPPs — you physically pay 80% of the contribution. The provider claims the remaining 20% from HMRC and adds it to your pot. Your total pension contribution is the full 100%.

For ANI purposes, HMRC deducts the full 100% — not the 80% you paid. A £800 payment to a RAS pension reduces your ANI by £1,000. This is correct. The pension received £1,000; you gave up £1,000 of income to fund it; your ANI should fall by £1,000.

The distinction matters when you are calculating whether a contribution will bring your ANI below a threshold. If your ANI is £101,000 and you want to bring it to £100,000, you need a £1,000 ANI reduction. Via RAS, that means an £800 cash payment to the pension. Via salary sacrifice or net pay arrangement, it means a £1,000 sacrifice.

Important: This article is for informational purposes only and does not constitute financial or tax advice. Based on 2026/27 HMRC rates which are subject to change. Individual circumstances vary significantly. Seek independent advice from a qualified financial adviser before making pension, Gift Aid, or salary sacrifice decisions. WageLab is not FCA regulated.

Use the WageLab calculator to see how these tax rules apply to your specific circumstances.

WageLab is not FCA regulated and does not provide financial advice. This article is for informational purposes only. Full article content coming soon.