Side Hustle Tax When You Earn Over £100k: The 60% Trap Explained

What is the 60% tax trap, in plain English?

The 60% effective tax rate is not an official tax band. It is the result of two things happening at once. First, income above £100,000 is taxed at the 40% higher rate. Second, for every £2 you earn above £100,000, HMRC removes £1 from your tax-free Personal Allowance. In 2026/27 the standard Personal Allowance is £12,570. By the time your income reaches £125,140, that allowance has been completely withdrawn.

The combined effect is brutal. You pay 40% tax on the extra income, and you also lose allowance that would have sheltered other income from tax, which costs you another 40% on that sheltered amount. Add those together and the effective rate is 60%. According to The Second Income UK, no other part of the UK income tax system produces an effective rate this high for an equivalent nominal band. For a side hustle earner already sitting near £100,000 in salary, this is the most important number in the tax calendar.

For a full grounding in how HMRC treats additional income streams, the second income tax guide covers the basics before you reach this level of complexity.

Worked example: a £130k salary plus a £10k side hustle

Here is a concrete illustration. Suppose your day-job salary is £130,000 in 2026/27. Your Personal Allowance is already fully withdrawn at that point, because £130,000 is above £125,140. You are paying 40% on income between £50,270 and £125,140, and 45% additional rate on everything above that.

Now add a £10,000 side hustle profit. That £10,000 sits entirely in the additional rate band, so it is taxed at 45%. You will also pay Class 4 National Insurance at 2% on profits above £12,570 (the lower profits limit for 2026/27), adding roughly £200. Your effective take on that £10,000 is around £5,300 after tax and NI, which is uncomfortable but not the worst scenario.

The nastier version is when your salary lands between £100,000 and £125,140. Say your salary is £110,000. You add a £10,000 side hustle. That extra income sits entirely within the taper zone. You pay 40% higher rate tax, plus you lose £5,000 of Personal Allowance (half of £10,000), which costs you another £2,000 in tax (40% of £5,000 lost allowance). Total extra tax: £6,000 on £10,000 of income. That is your 60% in action.

Who does this apply to, and who escapes it?

The taper catches anyone whose adjusted net income, which is gross income minus certain reliefs, crosses £100,000. That includes employment income, self-employment profits, rental profits, interest, and dividends above the dividend allowance. As Raisin explains in their overview of the £100k tax trap, the salary figure on your payslip is not the only thing that matters; it is your total adjusted net income that triggers the taper.

If your salary is, say, £95,000 and you earn a £10,000 side hustle profit, your adjusted net income becomes £105,000. You are now inside the taper zone for £5,000 of your allowance. You lose £2,500 of Personal Allowance, costing you an extra £1,000 in tax on top of the 40% you already pay. The first £5,000 of that side income costs 40%; the next £5,000 costs 60%.

Who escapes? If your employer handles bonuses via a salary sacrifice arrangement into a pension, those contributions reduce your adjusted net income before the taper calculation applies. Also, anyone earning above £125,140 from salary alone is already past the taper and into additional rate territory, so their side hustle income is taxed at a painful but simpler 45% (plus Class 4 NI) rather than the 60% effective rate.

How dividend income from your own limited company interacts with the taper

Many higher earners run a side hustle through a limited company and pay themselves via dividends. In 2026/27 the dividend allowance is £500. Dividends above that are taxed at 33.75% (higher rate dividend tax). But if those dividends push your adjusted net income above £100,000, or deeper into the taper zone, the effective rate climbs sharply.

The Second Income UK found that a director-shareholder with a £100,000 salary taking £10,000 in dividends faces the same taper mechanics as any other higher earner: the allowance is withdrawn, the 60% effective rate applies to the band where income and taper overlap. The fact that dividends carry a lower headline rate does not shelter them from the Personal Allowance withdrawal calculation.

One nuance: corporation tax has already been paid on the company's profit before it becomes a dividend. The Ltd company pays 19% (for profits up to £50,000) or up to 25% (for profits above £250,000) corporation tax. That reduces the pool available to distribute, so the combined tax burden, corporation tax on profits plus personal dividend tax plus allowance taper loss, can climb above 60% when all layers are counted.

For context on how HMRC treats side hustle income at the level of registration and reporting, HMRC's tax rules for side hustles gives a solid starting point before the Ltd question even arises.

Mitigation: the cleanest fixes available in 2026/27

Pension contributions

The most effective and widely used tool is a personal pension contribution. When you make a contribution to a pension, HMRC reduces your adjusted net income by the gross contribution amount. A £12,570 gross pension contribution (a typical figure chosen to bring adjusted net income back to exactly £100,000) can eliminate the taper zone entirely. Lloyds Bank's pensions guide on the 60% tax trap sets out how this works in practice, including the basic rate top-up added by the pension provider before HMRC processes the relief. You effectively get 60p of tax back for every £1 contributed into the taper zone, making pension saving exceptionally efficient at this income level.

Salary sacrifice

If your employer offers salary sacrifice for pension contributions, this is even cleaner because the sacrifice happens before PAYE is calculated, removing the income from your adjusted net income automatically. Love Electric's guide to salary sacrifice solutions for the 60% trap also covers electric vehicle salary sacrifice, which can reduce adjusted net income and carry additional tax efficiency. A £10,000 annual salary sacrifice into a pension or EV scheme could move £10,000 of income clean out of the taper zone.

Charitable giving via Gift Aid

Gift Aid donations also reduce adjusted net income for taper purposes. If you donate £4,000 to a registered charity under Gift Aid, the gross donation is £5,000, and that £5,000 is subtracted from your adjusted net income. For someone in the taper zone this means a £3,000 effective tax saving on a £4,000 cash donation, a 75% return of sorts, making Gift Aid one of the more powerful but underused levers available.

St. James's Place covers all three of these mitigation routes in detail if you want a professional financial planner's perspective before acting.

When the trap flips: above £125,140 the maths changes

Once your total income clears £125,140, the Personal Allowance is fully gone. There is no more taper to worry about. The effective rate does not drop to zero, obviously; it drops from 60% back to a still-significant 45% additional rate (47% for Scottish taxpayers on non-savings income in 2026/27, since Scotland applies its own bands above £75,000).

Class 4 National Insurance on self-employment profits adds 2% on profits above £12,570. So a self-employed side hustle profit above £125,140 of adjusted income costs you 47% in combined tax and NI (45% income tax plus 2% Class 4 NI). That is clearly cheaper than 60%, which is a strange thing to say but accurate. The Second Income UK explains this as the point where the marginal rate actually falls as income rises, a counterintuitive but mathematically real feature of the taper design.

This means that if your total income is hovering just above £100,000, a relatively modest side hustle could cost you far more per pound than a larger side hustle would cost a higher earner. The worst place to be is £100,001 to £125,139.

Practical checklist: should you take the side hustle through a Ltd, defer income, or accept the tax hit?

There is no single right answer, but here is a structured way to think through it. First, check where your salary sits before any side hustle income. If it is below £100,000, you may be outside the taper entirely, and the side hustle tax overview explains the standard rates that apply instead.

If your salary is between £100,000 and £125,140, run through this checklist:

• Can you make a pension contribution to bring your adjusted net income below £100,000? If yes, this is almost always the first move. The 60% effective relief makes it the most efficient savings decision available to you.
• Does your employer offer salary sacrifice? If yes, increasing your sacrifice to reduce adjusted net income is simpler than making personal contributions and claiming relief through Self Assessment.
• Is the side hustle income timing flexible? Sole trader and freelance income is taxable in the tax year it is earned. If you can defer invoicing to the next tax year, and that year your salary will be lower (perhaps due to a career change or retirement), deferring can move income out of the taper zone entirely.
• Is a limited company worth it? Retaining profits inside a limited company defers personal taxation. You only pay personal tax when you extract the income as salary or dividends. However, running a Ltd adds accountancy costs of roughly £800–£1,500 per year, and corporation tax has risen to up to 25%, so the numbers need careful modelling before assuming a Ltd saves money.
• Is the side hustle income below £1,000? If so, the trading allowance means you owe no tax at all, regardless of your salary, since the allowance shelters the first £1,000 of gross trading income.
• Have you factored in Class 4 NI? Self-employed profits above £12,570 attract Class 4 NI at 6% (up to £50,270) and 2% above that. At income levels we are discussing, the 2% rate applies, adding roughly £200 per £10,000 of profit above the taper zone.

As The Second Income UK recommends, anyone in this position should file a Self Assessment return accurately and on time. HMRC does not flag the taper issue proactively through PAYE; you discover the bill when you complete your return. If your total income could cross £100,000 in any tax year, register for Self Assessment early and plan contributions before 5 April.

Frequently Asked Questions

Sources

• HMRC: Tax rules for side hustles explained
• St. James's Place: How you can beat the 60% tax trap
• Lloyds Bank: How to avoid the 60% tax trap via pensions
• Love Electric: How to avoid the 60% tax trap via salary sacrifice
• Raisin: Understanding the £100k tax trap