0T Tax Code: What It Means for Your Pay

The 0T tax code appears on payslips more often than most people expect. It means HMRC has removed your personal allowance from that particular employment.

Every pound you earn gets taxed from the first, with no tax-free threshold.

The 0T tax code meaning is simple: HMRC lacks the details to assign your correct code. Or, your personal allowance has already been used up elsewhere.

Either way, you are likely paying more income tax than your situation requires.

Spotting a 0T tax code on your payslip can feel alarming at first. In most cases it is a temporary measure, not a permanent arrangement.

The OT tax code — the same code, different spelling — often follows a job change. A missing P45 or a first employment are the two most common triggers.

This guide covers why the 0T tax code appears and how it affects your pay. It also explains how to correct it and recover any tax you have overpaid. The 0T M1 and W1 variants, plus the Scottish SOT code, are covered too.

What Is the 0T Tax Code?

HMRC gives every PAYE employee a tax code. It tells your employer how much income to leave free of tax before deductions begin.

As an example for most people in 2025/26, that code is 1257L. It preserves £12,570 of annual earnings from income tax — the standard personal allowance for this tax year.

The 0T tax code removes that protection entirely. Tax applies from the first pound, with no tax-free amount at all. For a basic-rate earner, that can mean several hundred pounds extra deducted each month.

The spelling is worth clarifying upfront. The official HMRC code is 0T — a zero, then the letter T, not the letter O.

Many people search for ‘OT tax code’ because the zero looks like a capital O on a payslip. Both terms refer to the same code, and the correct form in HMRC records is always 0T.

Common Reasons HMRC Assigns a 0T Code

There are several situations that trigger a 0T. Some are temporary errors; others reflect a genuine tax position.

Starting a new job without a P45 is the most common cause. Your P45 carries your tax history from your previous employer. Without it, HMRC may lack what it needs to issue a correct code.

A new starter checklist can fill that gap. If you could not supply enough detail, the 0T code may still apply. It remains until HMRC receives the information it needs.

First-time employment is another trigger. With no prior tax record, HMRC uses a 0T while it confirms your position. Most first-time starters see this resolve within a few weeks.

Multiple jobs or pension income can also lead to a 0T. Your personal allowance applies to one income source only — typically the highest-paying one. For any additional role, the allowance may already be exhausted.

Taxable company benefits — private health cover, for example — can reduce your available allowance. If they reduce it to zero, the 0T code accurately reflects your position.

How a 0T Code Compares to BR

The 0T and BR codes are often confused because both remove the personal allowance. They work differently in practice, and the distinction matters most for higher earners.

The BR code applies a flat 20% basic rate to every pound from that source. It is predictable — you always pay 20%, nothing more.

The 0T code is progressive. It applies rates based on where your total earnings fall across the tax bands, without any tax-free offset.

The income tax rates under a 0T code for 2026/27 are:

• Basic rate — 20% on earnings up to £37,700.
• Higher rate — 40% on earnings from £37,701 to £125,140.
• Additional rate — 45% on earnings above £125,140.

These rates apply without any tax-free offset. As an example with a standard 1257L code, the first £12,570 is exempt before the bands begin.

For a basic-rate earner on £30,000, the 0T code results in roughly £6,000 in tax. Under a correct 1257L code, the figure drops to around £3,500.

For a higher-rate earner on £80,000, the excess tax under 0T can exceed £5,000 for the year. The longer the wrong code stays in place, the larger that gap grows.

Cumulative vs Non-Cumulative: M1 and W1 Suffixes

Your payslip may show 0T M1 or 0T W1 rather than a plain 0T. The suffix changes how tax is calculated each pay period. It also determines whether any overpayment corrects itself automatically.

A standard code is cumulative. Your employer tracks your earnings and tax paid across the full tax year to date.

If you overpaid in an earlier month, the system adjusts your deductions automatically in later ones.

• The M1 suffix signals monthly non-cumulative working. Each month is treated independently, as if it were the very first of the tax year. Overpayments from previous months do not feed into the calculation at all.
• The W1 suffix works the same way on a weekly pay cycle. Each week stands alone, with no year-to-date catch-up built into the payroll process.
• On 0T M1 or 0T W1, overpayments are unlikely to correct themselves through payroll. Contacting HMRC promptly is the most reliable way to limit the total amount withheld.

Is It an Emergency Code, and How Long Does It Last?

This question comes up regularly, and the answer is more nuanced than most people expect. The 0T tax code and emergency tax codes are related but distinct.

The recognised emergency codes end with a W1, M1, and X. These preserve the standard personal allowance but calculate tax on a non-cumulative basis.

The 0T tax code removes the personal allowance entirely — that is the key distinction. Emergency codes still grant you a tax-free threshold; the 0T code does not.

Most instances of the 0T tax code resolve within four to twelve weeks of HMRC receiving correct information. Processing times vary by workload and how quickly your employer applies the updated code.

If the code has not changed after two or three months, contact HMRC directly. Delays beyond that window can build a significant overpayment that takes longer to recover.

The SOT Code in Scotland

Scottish taxpayers may see SOT on their payslips instead of 0T. The S prefix means that Scottish income tax rates apply to that employment.

Scotland operates its own income tax rate structure, which differs from the rest of the UK. It has more bands, and several rates are set at different levels from the UK-wide equivalents.

The SOT code works in the same way as a standard 0T code in terms of what it removes. No personal allowance is applied, and the full income is subject to tax from the first pound.

The key difference is the rate schedule. Missing the S prefix can mean the wrong rates apply entirely, not just a missing allowance.

This matters most if you have recently moved between Scotland and another part of the UK. An incorrect S prefix can mean the wrong rate schedule is applied on top of a missing allowance.

If your residency has changed and your code does not yet reflect it, contact HMRC to update your record. An incorrect rate schedule compounds any overpayment from the missing allowance.

Recovering Overpaid Tax on a 0T Code

If a 0T code has led to higher deductions than you owed, a refund may be available. The process for recovering that money depends on when the overpayment occurred and how it was caused.

Overpayment in the Current Tax Year

Once HMRC updates your code, your employer adjusts future deductions through payroll. The cumulative PAYE system works backwards through the year to correct the balance.

Overpaid amounts from earlier months are often offset by reduced deductions going forward. In many cases, take-home pay rises noticeably once the correction is applied, without any separate claim needed.

Overpayment in a Previous Tax Year

If a 0T code was applied in error over the past four tax years, a backdated rebate may be available. HMRC issues a P800 tax calculation letter for each year it identifies an overpayment.

You may receive a P800 automatically at the end of the relevant tax year. In other cases, contacting HMRC directly is needed to prompt a review and start the refund process yourself.

Claims beyond four tax years are generally outside the permitted timeframe (eg the claim window for 2026/27 runs back to 2022/23), so acting promptly is important.

Acting Quickly to Limit the Overpayment

The most common reason refunds are delayed is late action after a job change. Each additional month on the wrong code adds to the total overpaid and the time it takes to recover.

Providing your P45 to your new employer on day one is the simplest way to avoid the 0T code altogether. Contact HMRC as soon as you notice a 0T on your payslip if that was not possible.

Next steps

The 0T tax code removes the personal allowance from a source of income. Every pound earned through that role is taxed until HMRC assigns the correct code.

It most often appears after a job change — particularly when a P45 is missing. It can also reflect a genuine position where the allowance is already committed elsewhere.

Knowing how 0T differs from BR and what the M1 and W1 suffixes mean helps you spot errors quickly.

Understanding the Scottish SOT variant ensures you are on the correct rate schedule. For more on tax codes and take-home pay, visit the tax codes section on taxrebateservices.co.uk.

Key Takeaways: 0T Tax Code at a Glance

• The 0T tax code removes your personal allowance, so income tax applies from the very first pound you earn in that employment.
• It is typically temporary, issued when HMRC lacks the information needed to assign your correct code — most often after a job change without a P45.
• Unlike the BR code’s flat 20%, the 0T code applies progressive rates: 20% at basic rate, 40% at higher rate, and 45% at additional rate.
• The 0T M1 and 0T W1 variants are non-cumulative — overpayments do not self-correct through payroll, so contacting HMRC promptly is advisable.
• Scottish residents may see SOT rather than 0T; both remove the personal allowance but SOT uses Scottish income tax rates.
• Overpaid tax can potentially be reclaimed for up to four previous tax years, either through automatic PAYE adjustment or by contacting HMRC directly.

Tax Code 0T FAQs

Q1  What does the 0T tax code mean?

The 0T tax code means HMRC has not applied a personal allowance to that employment. Every pound you earn from that job is taxed from the first, at whichever income tax rate applies to your total earnings. It is most often a temporary measure used while HMRC gathers the information it needs to assign your correct code.

Q2  Why do I have a 0T tax code?

The most common reason is starting a new job without providing a P45 or completing a starter checklist. Other causes include having multiple jobs where your personal allowance is already used up against another income, starting your first ever employment, or receiving taxable company benefits that reduce your available allowance to zero.

Q3  How much tax do I pay on a 0T tax code?

The 0T tax code applies income tax progressively: 20% on earnings up to £37,700, 40% on earnings between £37,701 and £125,140, and 45% above £125,140, all without any tax-free personal allowance. For a basic-rate earner on £30,000, that typically means paying around £2,500 more in tax than under a standard 1257L code for the year.

Q4  Is the 0T tax code an emergency tax code?

The 0T tax code is not officially classified as an emergency code, though it is triggered by similar circumstances. The recognised emergency codes for 2025/26 are 1257L W1, 1257L M1, and 1257L X, which preserve your personal allowance but calculate tax on a non-cumulative basis. The 0T code differs because it removes the allowance entirely.

Q5  Can I get a refund if I was on a 0T tax code?

If the 0T code was applied incorrectly and you overpaid tax as a result, a refund may be available. For the current tax year, overpayments are often corrected automatically through payroll once the right code is in place. For previous tax years, HMRC issues a P800 tax calculation letter, and you can reclaim overpaid tax going back up to four years.