Adjusted net income is your total taxable income for the year minus grossed-up Gift Aid donations and grossed-up pension contributions paid under relief at source, worked out before the Personal Allowance is applied. It is the figure HMRC uses to decide whether you keep your £12,570 Personal Allowance, how much Child Benefit you can retain, and whether you qualify for Tax-Free Childcare and the 30 free hours. Getting the number wrong by a few hundred pounds can push you across a threshold and cost you thousands.
The Four Steps HMRC Uses
The calculation is set out in the Income Tax Act 2007, and the order of the steps matters.1Legislation.gov.uk. Income Tax Act 2007 – Section 58
Step 1. Work out your net income. Add up every source of taxable income for the tax year (employment, self-employment, pensions, savings interest, dividends, rental income, taxable state benefits, trust distributions, and estate income), then subtract reliefs that apply at this stage such as trading losses or property losses. The result is your net income.2GOV.UK. Personal Allowances: Adjusted Net Income
Step 2. Subtract grossed-up Gift Aid donations. Take the cash amount you actually donated and multiply by 100/80 to reflect the basic-rate tax the charity has reclaimed. A cash donation of £800 has a grossed-up value of £1,000, and it is that £1,000 you deduct.1Legislation.gov.uk. Income Tax Act 2007 – Section 58
Step 3. Subtract gross pension contributions paid under relief at source. If your pension provider claims basic-rate tax back from HMRC on your behalf, gross up the amount you paid using the same 100/80 formula and deduct that figure.3GOV.UK. Tax on Your Private Pension Contributions: Tax Relief Personal pensions and stakeholder pensions typically operate this way. If £400 leaves your bank each month, the gross contribution is £500 and the annual Step 3 deduction is £6,000.
Step 4. Add back any deduction you claimed at Step 1 for payments to a trade union or police organisation. Most people never need this step.
The figure you land on is your adjusted net income for the tax year.
What Counts as Income at Step 1
Everything taxable feeds the starting total. Salary, bonuses, and overtime are obvious. Self-employment profits go in at the full amount before any pension or charitable adjustments. Taxable state benefits count too, including the State Pension, Jobseeker’s Allowance, Carer’s Allowance, and contribution-based Employment and Support Allowance.4GOV.UK. Income Tax: Tax-Free and Taxable State Benefits Savings interest and dividends are included even though they have their own separate allowances for tax calculation. Rental income, trust distributions, and income from a deceased person’s estate all form part of the total.
Benefits in Kind
Non-cash perks from an employer, such as a company car, private medical insurance, or gym membership, are taxable income reported through payroll or on a P11D at the end of the tax year.5GOV.UK. Reporting and Paying Expenses and Benefits for Employers These add to your starting income and therefore push up your adjusted net income. People close to a threshold often overlook them and get an unpleasant surprise when HMRC’s figures come in higher than expected. Check your P11D and payslip carefully if your employer provides any non-cash benefits.2GOV.UK. Personal Allowances: Adjusted Net Income
Salary Sacrifice and Net Pay Pensions
If your employer runs a salary sacrifice arrangement for pension contributions, your contractual salary is reduced before tax is calculated. That lower salary is what appears on your P60 and feeds Step 1, so the pension contribution never enters the adjusted net income calculation separately.6GOV.UK. Salary Sacrifice Reform for Pension Contributions The same applies to workplace schemes using a net pay arrangement, where contributions come out of gross pay before tax.7GOV.UK. PTM044230 – Contributions: Tax Relief for Members: Methods: Net Pay Your starting income is already reduced, so you do not deduct the pension again at Step 3. Only relief-at-source contributions belong at Step 3.
Deductions That Bring the Figure Down
Gift Aid Donations
Charitable donations made through Gift Aid are one of the most commonly used tools for pulling adjusted net income below a threshold. You deduct the grossed-up value at Step 2, not the cash you handed over. A £4,000 donation grosses up to £5,000 and the full £5,000 comes off.8GOV.UK. HS342 Charitable Giving Higher-rate and additional-rate taxpayers also get extended basic and higher rate bands as a result, which further reduces the tax owed.
Relief-at-Source Pension Contributions
Contributions to a personal pension paid from after-tax income are grossed up at Step 3 using the 100/80 formula.3GOV.UK. Tax on Your Private Pension Contributions: Tax Relief For someone hovering near £100,000, switching from relief at source to salary sacrifice can produce the same adjusted net income with less paperwork and less room for error, because salary sacrifice reduces pay before Step 1 rather than requiring a Step 3 adjustment.
Trading and Property Losses
Self-employed people can subtract qualifying trading losses from total income at Step 1, before Gift Aid or pension adjustments. Property losses work similarly.2GOV.UK. Personal Allowances: Adjusted Net Income A bad year in business can protect your Personal Allowance or childcare eligibility, but only if you claim the loss relief on your return.
Professional Subscriptions
Annual fees paid to HMRC-approved professional bodies and learned societies are deductible from employment income if the membership is relevant to your job. HMRC publishes an approved list running from the British Medical Association to the Royal Institution of Chartered Surveyors.9GOV.UK. List of Approved Professional Organisations and Learned Societies (List 3) The deduction reduces your employment income at Step 1. You cannot claim relief for fees your employer paid on your behalf, or for one-off life memberships.
Why the Number Matters
The £100,000 Personal Allowance Taper
The Personal Allowance for the 2025/26 tax year is £12,570. Once your adjusted net income exceeds £100,000, the allowance shrinks by £1 for every £2 above the threshold, and it disappears entirely at £125,140.10GOV.UK. Income Tax Rates and Personal Allowances11Legislation.gov.uk. Income Tax Act 2007 – Section 35
The result is one of the sharpest marginal rates in the system. On each extra £2 earned in that band, you pay 40% tax on the £2 and also lose £1 of tax-free allowance, meaning another £1 of your existing income is now taxed at 40%. The combined effect is an effective 60% marginal rate across the whole £100,000 to £125,140 band. A pension contribution or Gift Aid donation that pulls adjusted net income from £102,000 down to £99,000 saves the 40% tax on £3,000 and also restores £1,500 of Personal Allowance, adding a further £600 of tax saved.
The High Income Child Benefit Charge
If you or your partner receives Child Benefit and one of you has adjusted net income above £60,000, the higher earner pays the High Income Child Benefit Charge. For every £200 of income above £60,000, you repay 1% of the Child Benefit received that year, so the whole benefit is clawed back by £80,000.12GOV.UK. High Income Child Benefit Charge: Overview The charge is based on individual adjusted net income, not household income. A couple earning £59,000 each keeps everything; a household with one earner on £80,000 loses the lot. The threshold rose from £50,000 to £60,000 from the 2024/25 tax year, so anyone who used to sit safely below the old limit should check the new one.
Tax-Free Childcare and 30 Free Hours
Eligibility for Tax-Free Childcare and the extended 30-hours free childcare entitlement both require adjusted net income of £100,000 or less per parent. If either parent goes over in the relevant tax year, the family loses both.13GOV.UK. Adjusted Net Income – Tax-Free Childcare Technical Manual Tax-Free Childcare provides up to £2,000 per child per year, or £4,000 for disabled children, so losing eligibility hits families with young children hard. Because the childcare cap and the Personal Allowance taper share the same £100,000 trigger, going even slightly over costs you both at once.
If You’re Sitting Near a Threshold
Several legitimate levers can pull the figure down. Increasing pension contributions is usually the most effective. Salary sacrifice is the cleanest method because it reduces contractual pay before Step 1.6GOV.UK. Salary Sacrifice Reform for Pension Contributions If salary sacrifice isn’t available, paying into a relief-at-source pension and grossing up at Step 3 gets you to the same place.
Gift Aid works well if you already give to charity. The grossed-up deduction reduces adjusted net income pound for pound, and you can carry a donation back to the previous tax year, which is useful if you only realise you were over a threshold after the year has ended but before you file.
Self-employed people should think about the timing of loss relief. A loss claimed against total income in a year when you’re near £100,000 or £60,000 protects your allowances; carrying it forward to a lower-income year may not.
Getting It Wrong
Errors in your adjusted net income figure ripple through every threshold it touches. Understate your income and you may claim childcare support or Personal Allowance you weren’t entitled to. HMRC can charge penalties on the additional tax that results, and the rate depends on how the error happened: a careless mistake can attract up to 30% of the extra tax due, and deliberate or concealed errors carry higher penalties.14GOV.UK. Penalties: An Overview for Agents and Advisers
Most errors are not deliberate. They come from forgetting to include savings interest, overlooking a P11D benefit, or grossing up pension contributions the wrong way. If you spot a mistake after filing, telling HMRC voluntarily typically reduces any penalty substantially compared with waiting for HMRC to find it.