The £100k Tax Trap: Why Earning More Can Leave You With Less

You've worked hard to increase your income. But is your money working just as hard to build your future?

You've worked hard for that promotion, pay rise or bonus. You've built a successful career, taken on more responsibility and perhaps finally reached that six-figure salary you've been working towards.

But here's something worth thinking about.

Just because you're earning more, does that mean you're actually building more wealth?

Because earning £100,000 a year and building long-term financial security are two very different things.

And there's something else that might surprise you. Once your income crosses £100,000, the UK tax system can take a considerably bigger share of your earnings than you might expect.

What Is the £100k Tax Trap?

The £100k tax trap refers to an effective 60% marginal income tax rate that applies to income between £100,000 and £125,140 in England, Wales and Northern Ireland.

For the 2026/27 tax year, most people are entitled to a tax-free Personal Allowance of £12,570.

However, once your adjusted net income exceeds £100,000, you begin losing £1 of that allowance for every additional £2 you earn.

By £125,140, your Personal Allowance has disappeared completely.

Because you're paying 40% income tax while also losing your tax-free allowance, the effective marginal income tax rate becomes 60%. For employees, National Insurance can increase the combined marginal deduction to 62%.

HMRC — Income Tax rates and Personal Allowances

What Does This Mean in Practice?

Imagine you're earning £100,000 and receive a £10,000 bonus.

You might expect to keep £6,000 after paying 40% income tax.

But because your income has increased to £110,000, you also lose £5,000 of your Personal Allowance.

The result?

You pay approximately £6,000 in additional income tax on that £10,000 bonus.

You're left with just £4,000 before National Insurance.

And if you have young children, the financial implications can be even greater.

The Hidden Impact on Working Parents

For working parents, crossing the £100,000 threshold can have consequences beyond income tax.

If either parent expects their adjusted net income to exceed £100,000, the household may lose eligibility for Tax-Free Childcare and the additional government-funded childcare available to eligible working parents in England.

Tax-Free Childcare alone can be worth up to £2,000 per child annually, or £4,000 for a disabled child.

Depending on your circumstances, losing childcare support could mean that a pay rise or bonus leaves your household financially worse off.

This is why understanding your finances becomes increasingly important as your income grows.

HMRC — Tax-Free Childcare

How Can You Reduce the £100k Tax Trap?

The good news is that there are legitimate, tax-efficient ways to manage your adjusted net income.

1. Pension Contributions

One of the most effective options can be increasing your pension contributions.

If you're earning £110,000, an eligible £10,000 gross pension contribution could reduce your adjusted net income to £100,000, potentially restoring your full Personal Allowance.

In this example, the £10,000 contribution could effectively cost you approximately £4,000 after income tax relief.

Rather than receiving £4,000 today, you could have £10,000 invested towards your retirement.

And that money has the potential to grow over time.

The precise tax relief depends on how your contributions are made. Pension money is generally inaccessible until the minimum pension age, and contribution limits apply.

For 2026/27, the standard pension annual allowance is £60,000, although it may be lower depending on your circumstances.

HMRC — Tax relief on pension contributions

2. Gift Aid Donations

Eligible charitable donations made through Gift Aid can also reduce your adjusted net income.

If charitable giving is already part of your financial plans, understanding the tax treatment could be beneficial.

3. Understand Your Total Income

Your adjusted net income isn't necessarily the same as your salary.

Bonuses, dividends, taxable savings interest and rental profits can all affect the calculation.

Understanding your overall income position allows you to make more informed financial decisions before the tax year ends.

A Six-Figure Salary Doesn't Guarantee Financial Freedom

This is where I believe the conversation needs to go beyond tax.

After more than 25 years working in investment banking, one of the most important lessons I've learned is that earning money and building wealth require two very different approaches.

You can have an excellent salary, a successful career and a comfortable lifestyle, yet still feel uncertain about your financial future.

Perhaps you have substantial savings sitting in cash. Maybe you've accumulated pensions from several employers but haven't reviewed how they're invested. Or perhaps you know you should be investing more, but you're unsure where to start.

A high income gives you the opportunity to build wealth. It doesn't automatically create it.

Building wealth means understanding what happens to the money you earn.

How much should you keep in cash? How much should you invest? Are you making the most of your pension and ISA allowances? And are your investments aligned with your long-term goals?

Because ultimately, wealth isn't simply about accumulating money.

It's about creating choices.

The choice to reduce your working hours, change careers, start a business or retire when you're ready, rather than when you can finally afford to.

That's what becoming Wealth Intelligent is about. Understanding your finances, making informed decisions and building a future where you have greater financial freedom.

Frequently Asked Questions

At What Income Does the £100k Tax Trap Start?

The Personal Allowance taper begins when your adjusted net income exceeds £100,000. You lose £1 of your allowance for every additional £2 earned.

Can Pension Contributions Reduce the 60% Tax Trap?

Yes. Eligible pension contributions can reduce adjusted net income and potentially restore some or all of your Personal Allowance. The amount of relief depends on your circumstances.

Does My Bonus Count Towards the £100,000 Threshold?

Yes. Bonuses count towards your adjusted net income, along with other taxable income such as dividends, savings interest and rental profits. Eligible deductions, including certain pension contributions, can reduce the final figure.

You've Built Your Career. Now Build Your Wealth.

If you're approaching or already earning £100,000, you've achieved something significant.

But don't assume that a six-figure salary means your financial future is taken care of.

Take the time to understand your tax position, review your pensions and investments, and consider whether the decisions you're making today are helping you build the future you want.

Because the goal isn't simply to earn more.

It's to build enough wealth that one day, working becomes a choice rather than a necessity.

You've spent years investing in your career.

Now it's time to invest in your financial future.

Ready to Make Your Money Work Harder?

If you're earning a good income but aren't sure whether you're making the most of it, I can help you understand your financial position and develop a clearer plan for building long-term wealth.

Book a free 20-minute Wealth Strategy Call to explore where you are today and what you want to achieve.