What Is the Tax-Free Personal Allowance and How Does It Work?

Everyone in the UK gets a personal allowance before they pay a single pound of income tax — but not everyone knows what it does, how much it is, or how to keep it intact. The tax-free personal allowance is the chunk of income you earn each year that HMRC won't tax. For the 2025/26 tax year, that's £12,570. Earn below that and you pay no income tax. Earn above it and you only pay tax on the overage. But here's the catch: if you earn over £100,000, that allowance shrinks. For every £2 you earn above that threshold, you lose £1 of your allowance. Lose it all at £125,140, and suddenly you're in a 60% marginal tax band. This guide explains how the personal allowance works, who's affected, and how to make sure you're not overpaying.

What Is the Personal Allowance?

The personal allowance is a threshold — the amount of income that's exempt from income tax. It's not a rebate, not a credit, not a deduction. It's simply income you don't pay tax on at all.

For the 2025/26 tax year, the income tax bands are:

Personal allowance: £0–£12,570 — no income tax
Basic rate band: £12,571–£50,270 — 20% income tax
Higher rate band: £50,271–£125,140 — 40% income tax
Additional rate: £125,141+ — 45% income tax

When a job advert says "£35,000 a year," that's gross. You don't pay tax on the first £12,570. You pay 20% on the remaining £22,430, which is £4,486. Your net pay before National Insurance is £30,514. The personal allowance is why.

These thresholds are set by HMRC each April. The personal allowance stayed at £12,570 for five years between 2017 and 2022 — not because it's a magic number, but because the government chose to freeze it. It's reviewed annually, so check GOV.UK each April for the current year's figures.

How the Taper Works — and the 60% Marginal Rate

Here's where many high earners stumble. If your income exceeds £100,000, your personal allowance doesn't just reduce gently. It shrinks by £1 for every £2 you earn over the threshold. This creates an effective tax bracket that's far steeper than 40%.

Worked example:
You earn £110,000. That's £10,000 over the £100,000 taper threshold. You lose half of that in personal allowance: £5,000. So instead of £12,570 tax-free, you only get £7,570. The £5,000 of lost allowance is now taxed at your marginal rate (40% income tax, plus 2% National Insurance contributions above the upper earnings limit). That's 42% on the lost allowance itself — plus you've forfeited the tax relief the allowance would have given you, another 20% in effective terms.

For income between £100,000 and £125,140, the true marginal rate is 60%: 40% income tax plus 2% National Insurance plus the hidden cost of the lost allowance. It's an easy trap for contractors, freelancers, and business owners who don't expect a sudden spike in their tax bill.

Your Tax Code Tells You How Much Allowance You Have

Your payslip has a tax code. If you're a standard employee earning under £100,000, it probably says 1257L. That "1257" is shorthand for £12,570 — your personal allowance. The "L" means you get the basic rate allowance.

If your code is different — maybe K, T, or a number that doesn't match £12,570 — it means HMRC is adjusting your allowance because:

You have a second job, and HMRC split the allowance between them
You owe tax from a previous year
You have benefits liable to income tax (e.g., a company car)
Your employer applied an emergency code because they don't have your details
You're using the Marriage Allowance and have transferred some of it to your partner

An incorrect code can mean you're overpaying tax every single month. If you think yours is wrong, check it on the HMRC website or call the tax helpline (0300 200 3300, free from most phones).

Strategies to Protect Your Personal Allowance

Understand the £100,000 taper. If you're close to six figures, paying 60% marginal tax on the lost allowance is a serious cliff edge. Some people structure bonuses or pension contributions to stay below the threshold. Others accept the taper as the cost of higher income. You can't dodge it legally, but you can plan for it.

Claim the Marriage Allowance. If you're married or in a civil partnership, and one of you earns under £12,570 while the other earns between £12,570 and £50,270, you can claim the Marriage Allowance. The lower earner transfers 10% of their personal allowance (£1,257) to the higher earner. That saves £251 per year at basic rate tax. Apply on GOV.UK in five minutes, and you can backdate it up to four years.

Don't waste your allowance on low-interest savings. Your personal allowance is most valuable for income taxed at your marginal rate. Basic rate savers get a £1,000 savings allowance; higher rate savers get £500. These cover most savings interest before the personal allowance is needed.

Separate your allowances. You get £12,570 personal allowance per year for all income. You also get a £20,000 ISA allowance per year for savings and investments (interest and growth tax-free). These are independent. If you earn £12,570 from a job and put £20,000 into an ISA, both work at full value.

Self-employed? Track your actual profit. Your personal allowance works the same way — £12,570 is tax-free. But you only pay income tax on profit, not turnover. If you sell £40,000 of goods but spend £25,000 on stock, premises, and costs, your profit is £15,000. You pay tax on £2,430 (£15,000 minus the allowance), not £40,000. Keep detailed records of every business expense. If your profit is under £1,000, the tax-free trading allowance simplifies things.

Understand dividend tax. Company owners and shareholders have a separate £500 dividend allowance — £500 of dividends per year, tax-free. This is in addition to your personal allowance, not instead of it. Dividends are taxed after your personal allowance is used up.

Common Mistakes That Cost You Money

Missing the trader's allowance. If you're self-employed and profit under £1,000, you can claim the trading allowance and pay no income tax on that profit — without proving individual expenses. Many freelancers don't know this exists.

Ignoring your tax code. An emergency code means you might overpay tax from salary, only to reclaim it later. That's a short-term loan to HMRC at zero interest. Fix it now.

Not spreading income across partners. You can't split one job's salary, but if you're in a partnership, you can split partnership profit. Both partners get a personal allowance, so you can earn up to £25,140 combined before paying income tax.

Forgetting Marriage Allowance. One application (10 minutes, free) saves £251 per year. Backdate it four years, and that's up to £1,004.

Frequently Asked Questions

Q: Is the personal allowance the same as a tax-free allowance?
A: Yes. The personal allowance is the main tax-free threshold. There are others for specific income types — trading allowance (up to £1,000 profit for self-employed), savings allowance (£1,000 for basic rate, £500 for higher rate), and dividend allowance (£500). But "personal allowance" always means the £12,570 threshold for employment and self-employment income.

Q: What happens if I don't earn enough to use my personal allowance?
A: Nothing bad. If you earn £8,000, you don't get a refund or credit for the unused £4,570. It simply doesn't exist next year; the allowance resets each tax year. That's why Marriage Allowance is valuable — the lower earner's unused allowance transfers to the higher earner.

Q: Do I pay National Insurance on the personal allowance?
A: No. National Insurance is separate. It applies to earnings above £11,908 (2025/26). So earning £12,570 means no income tax (due to the allowance) but some National Insurance.

Q: Does the personal allowance apply to pensions, dividends, and investment income?
A: The personal allowance applies to all income types. But investment income has its own allowances: savings allowance for interest, dividend allowance for dividends. If you earn employment income, investment income, and have a pension, they all count toward one personal allowance threshold.

Q: If I have two jobs, do I get two personal allowances?
A: No. One allowance of £12,570 per tax year, regardless of job count. HMRC usually assigns it to your main job and gives an emergency code (no allowance) on the second job. You reclaim overpaid tax at year-end on self-assessment.

Q: Can I carry forward an unused allowance to next year?
A: No. It's use-it-or-lose-it each tax year. However, you can transfer unused allowance to your spouse via the Marriage Allowance.

Q: What if I move abroad — do I lose the allowance?
A: It depends on residency and immigration status. UK residents get the full allowance. Non-residents and temporary residents have different rules. If you're moving, check HMRC's residency guidance before you go.

Q: When does the age-related allowance kick in?
A: The main personal allowance (£12,570) applies from age 16 to 64. From age 65, you might get a higher age-related allowance, though this is being phased out. Check current age-related rates on GOV.UK — they change every tax year.

See Your Exact Numbers

Your personal allowance is the foundation of your UK tax bill. The UK income tax guide breaks down how all the bands work together. Once you understand the allowance, the rest makes sense. Run your actual salary through a calculator to see exactly how much of your gross pay becomes take-home after the allowance, income tax, and National Insurance all apply.