How to Optimise Your 2026/27 Tax Year (Starting Now)

The New Tax Year Is Here — What's at Stake?

April 6th marks the start of the 2026/27 UK tax year, and if you earn between £100,000 and £125,140, the clock is already ticking.

That income band is where the £100k personal allowance trap hits hardest. For every £2 you earn above £100k, you lose £1 of your £12,570 tax-free Personal Allowance — creating an effective 60% marginal tax rate. Add National Insurance and you're looking at 62%. That's higher than the 45% additional rate paid by those earning over £125,140. If you're not familiar with how the trap works, we break it down in detail in our £100k tax trap guide.

The trap doesn't just hit your tax bill. Earning above £100,000 adjusted net income can also affect your eligibility for 30 hours free childcare and Tax-Free Childcare — benefits worth thousands per year to families with young children.

For a full breakdown of what you could be losing and how to check your position, try our UK tax calculator or work through the tax optimisation checklist.

The Solution: Salary Sacrifice

The most effective way to bring your adjusted net income (ANI) below £100,000 is salary sacrifice — typically into your workplace pension.

With salary sacrifice, you agree to reduce your contractual gross pay. Your employer redirects that amount into your pension before tax and National Insurance are calculated. This means:

• Your adjusted net income drops, preserving your Personal Allowance
• You save on income tax at your marginal rate (effectively 60% in the trap band)
• You save on employee National Insurance (2% above the Upper Earnings Limit)
• Your employer saves on employer National Insurance (15%) — and many will pass some of that saving back to you
• Your pension grows tax-free

Other salary sacrifice schemes — such as cycle-to-work, electric car leasing, or additional holiday purchase — can also reduce your ANI, though pension contributions offer the greatest impact.

For someone earning £120,000, sacrificing £20,000 into their pension to hit the £100k threshold doesn't cost £20,000 in take-home pay. Thanks to the 60% marginal rate, it costs closer to £7,600 — meaning £12,400 goes straight to tax and NI savings, all landing in your pension pot.

We'll cover the mechanics of salary sacrifice in more detail in a dedicated article soon. In the meantime, our salary sacrifice calculator can model your exact position.

Why Starting Early Matters (With Examples)

Here's the part most people miss: salary sacrifice must be planned in advance. You can only sacrifice future salary — you can't retrospectively reduce pay you've already received. And your employer can't reduce your pay below the National Minimum Wage (approximately £2,000/month for a full-time worker in 2026).

This creates a simple but brutal constraint: the later you start, the harder it gets.

Let's look at three scenarios for someone earning £120,000/year (£10,000/month gross) who needs to sacrifice £20,000 to bring their ANI down to £100,000:

Scenario 1: Start in April 2026 (12 months available)

• Monthly sacrifice needed: £1,667
• Monthly gross after sacrifice: £8,333
• Feasible? Absolutely — comfortable and sustainable
• Result: Full £12,570 Personal Allowance restored. Maximum tax savings achieved.

Starting from day one spreads the sacrifice evenly. You barely notice the difference month-to-month, and your pension benefits from a full year of contributions and growth.

Scenario 2: Start in November 2026 (5 months remaining)

• Salary already earned: £70,000 (April–October)
• Monthly sacrifice needed: £4,000
• Monthly gross after sacrifice: £6,000
• Feasible? Yes, but it's tight

You can still hit the £100k target, but you're sacrificing 40% of your remaining gross pay each month. That's a significant hit to your disposable income — especially over the winter months when household costs tend to be higher. Many people in this position either can't afford the reduced take-home or aren't willing to accept it, and end up only partially optimising.

Scenario 3: Start in February 2027 (2 months remaining)

• Salary already earned: £100,000 (April–January)
• Monthly sacrifice needed: £10,000 (your entire remaining salary)
• Feasible? No — it's impossible

Your employer cannot reduce your pay below National Minimum Wage. With a minimum gross of approximately £2,000/month, the maximum you can sacrifice is £8,000/month — or £16,000 over two months.

That leaves you £4,000 short. Your ANI lands at £104,000 instead of £100,000, meaning you still lose £2,000 of your Personal Allowance and pay roughly £1,200 more in tax than if you had started earlier.

You've done a lot of effort for an incomplete result — simply because you ran out of time.

The Takeaway

The exact same £120,000 salary produces three very different outcomes depending on when you start planning. April gives you full control. November makes it painful. February makes it impossible.

How TaxPilot Can Help

This is exactly what TaxPilot was built for.

Our UK tax calculator lets you enter your salary, bonuses, and benefits to see your exact position in the £100k trap. You can model different salary sacrifice amounts and instantly see the impact on your take-home pay, tax bill, and childcare eligibility.

Whether you're planning for the full year ahead or trying to work out what's still achievable, TaxPilot shows you the numbers that matter — so you can make informed decisions, not guesses.

The 2026/27 tax year started today. The earlier you plan, the more options you have — and the more you save.

Try the TaxPilot calculator now →