BRM1 Tax Code Explained: What BR M1 Means for Your Pay in 2026/27

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Last Updated On – 05-10-2026

Seeing BR M1, sometimes written as BRM1, on a payslip can be confusing, especially if it appears after starting a new job, taking a second job or receiving pension income.

BR M1 is not a special business tax regime, a penalty or a code for “high-risk” taxpayers.

It is a PAYE instruction telling payroll two important things: BR means income from that particular job or pension is taxed at the basic rate, while M1 means the calculation is being operated on a Month 1, non-cumulative basis.

For 2026/27, the standard Personal Allowance remains £12,570, while the basic Income Tax rate for England and Northern Ireland remains 20%.

The correct code for an individual, however, depends on all their employment, pension and allowance circumstances.

What Does the BRM1 Tax Code Mean?

The BRM1 tax code is better understood when separated into BR and M1.

HMRC defines BR as a code under which all income from that particular employment or pension is taxed at the basic rate. It is usually associated with someone who has more than one employment or pension because their Personal Allowance may already be allocated elsewhere.

You can check the official definitions through what your tax code means.

M1 has a different function. It tells payroll that the code is being operated on a Month 1 basis.

Rather than looking at income and tax from the beginning of the tax year, payroll calculates the current month independently.

So BR M1 effectively combines:

BR: Tax the income at the basic rate.
M1: Do not perform the normal cumulative year-to-date calculation.

A closely related issue is whether BR is an emergency tax code. BR on its own is not one of HMRC’s standard emergency markers; the M1 element is what indicates emergency or non-cumulative treatment.

Why Might HMRC Use a BR M1 Tax Code?

HMRC Use a BR M1 Tax Code

There is no single reason why BR M1 may appear.

In many cases, it reflects HMRC or payroll working with incomplete or changing information rather than anything being wrong with the taxpayer.

Common situations include:

Starting a second job.
Receiving income from more than one pension.
Beginning a new job before previous employment details have been fully processed.
Payroll not having complete previous pay and tax information.
Starting pension income.
A temporary change while HMRC reviews employment records.
Special payroll circumstances requiring basic-rate Month 1 treatment.

HMRC’s published rules show that BR is normally appropriate where all income from a job or pension should be taxed at the basic rate, while M1 tells payroll to use only the current month’s figures.

Second Jobs and Pensions

A second job is one of the clearest examples.

Suppose someone has:

Main job: £30,000
Second job: £6,000

Their £12,570 Personal Allowance may already be allocated to the main employment.

If HMRC expects the second job’s earnings to remain within the basic-rate band, BR can be an appropriate code for that second employment.

The important question is therefore not simply “Is BR bad?” but “Is BR being used on the correct income source?”

Someone with several PAYE sources may legitimately have different codes for each one.

Why Does M1 Change How PAYE Is Calculated?

Most ordinary PAYE codes operate cumulatively.

A cumulative code looks at:

Income received since 6 April.
Tax already deducted.
Personal Allowance used so far.
Unused allowance from earlier periods.
The taxpayer’s overall PAYE position during the year.

Month 1 treatment does not do that.

Each monthly payment is considered independently.

Feature	Cumulative calculation	M1 calculation
Earlier income considered	Yes	No
Earlier PAYE considered	Yes	No
Current month considered	Yes	Yes
Unused earlier allowance considered	Usually	No
Can rebalance previous PAYE automatically?	Often	Not through the M1 calculation

This is the same core principle explained in more detail for non-cumulative tax codes.

HMRC’s current emergency-code guidance confirms that M1 means tax is calculated using the current month’s pay rather than total income for the tax year so far.

The official explanation is available under emergency tax codes.

Is BR M1 the Same as the Standard Emergency Tax Code?

No.

This distinction is important for 2026/27.

HMRC’s standard emergency-code baseline is 1257L, with emergency operation shown as:

1257L W1
1257L M1
1257L X

The standard Personal Allowance for 2026/27 is £12,570. HMRC’s published PAYE starting points are £242 per week and £1,048 per month.

BR M1 is different because BR does not allocate the £12,570 Personal Allowance to that income source.

Compare the two:

Code	Personal Allowance	Tax treatment	Basis
1257L	£12,570 normally	Normal tax bands	Usually cumulative
1257L M1	One month’s share of standard allowance	Normal tax bands	Non-cumulative
BR	None through that source	Basic rate	Normally basic-rate treatment
BR M1	None through that source	Basic rate	Non-cumulative

Someone wanting to understand the distinction in more detail can compare BR M1 with the 1257L M1 tax code.

How Much Tax Do You Pay on BR M1?

For an employee in England or Northern Ireland, BR normally means 20% Income Tax is deducted from all taxable pay from that employment or pension.

There is no Personal Allowance allocated against that source.

For example:

Monthly BR M1 income	Approximate Income Tax at 20%
£1,000	£200
£1,500	£300
£2,500	£500
£3,000	£600
£4,000	£800

These simplified examples ignore National Insurance, pension deductions, student loans and other payroll adjustments.

BR M1 should also not be confused with National Insurance. A PAYE tax code determines how Income Tax is deducted; National Insurance uses separate categories and thresholds.

Can BR M1 Make You Pay Too Much Tax?

Yes, but not in every case.

BR M1 may result in excessive deductions where the code is being used on someone’s main or only employment even though they are entitled to unused Personal Allowance.

For example, suppose a monthly-paid employee earns £2,500 and would ordinarily qualify for the standard £12,570 Personal Allowance.

With BR:

£2,500 × 20% = £500

A simplified calculation using one month’s standard Personal Allowance would leave approximately £1,452.50 taxable:

£2,500 − £1,047.50 = £1,452.50

At 20%, that is approximately:

£290.50

The difference is approximately £209.50 for that month.

Actual payroll calculations can differ, but the example shows why an unexpected BR code on someone’s only job deserves checking.

It can also work in the opposite direction.

If someone has substantial combined income and part of their second-job income should actually fall into the higher-rate band, taxing the entire second employment at 20% could lead to too little tax being deducted.

BR therefore does not automatically mean overpayment.

Is BR M1 Normal for a Second Job?

It can be.

HMRC usually allocates tax-free allowances according to the taxpayer’s overall PAYE record.

If the Personal Allowance is already being used against the main job, the second job may receive BR so that the additional income is taxed from the first pound.

This can be appropriate where that second income falls entirely within the basic-rate band.

However, BR may need reviewing where:

Your second job pushes total income into higher-rate tax.
BR appears on your main job instead of the secondary one.
An old employment is still shown as active.
HMRC has allocated your allowance to the wrong source.
Your employment circumstances recently changed.

If several codes appear across different employers, it is worth checking whether your tax code is correct rather than judging one code in isolation.

Why Can BR M1 Appear After Starting a New Job?

New employment is a common time for PAYE problems to appear.

Your employer normally uses your P45 to establish your previous pay, tax and tax-code information.

If a P45 is unavailable, the employer should obtain the relevant information through the starter process.

HMRC says an emergency code may be used where your new employer does not yet have previous income and tax details.

Once information from your old and new employers has been received, HMRC can update the code.

Missing or incorrect starter information can also lead to BR or 0T being applied temporarily. HMRC specifically identifies this issue in its guidance for people whose codes change after starting a new job.

The 35-Day Rule

The frequently quoted 35-day period needs to be understood correctly.

HMRC says that after someone starts a new job, updating the tax code after receiving the necessary employment information can take up to 35 days from the date the job started.

That does not mean every tax-code correction takes 35 days.

If you use HMRC’s service to correct information yourself, HMRC says it will normally tell you and your employer the new code within 15 working days.

For a monthly-paid employee, the new code should normally appear on the next or following payslip.

Can Your Employer Change BR M1 for You?

Not simply because you ask payroll to use a different code.

Employers have to operate the PAYE code they are authorised to use.

A payroll department can:

Check which code is currently recorded.
Check whether your P45 was processed.
Confirm starter information.
Confirm whether a later coding notice has been received.
Apply a new code once HMRC instructs them to do so.

But payroll should not simply replace BR M1 with 1257L because an employee believes the latter is correct.

HMRC issues coding notices to employers when a code needs changing. Employers are expected to update payroll records when they receive the instruction.

How Can You Fix an Incorrect BR M1 Tax Code?

Start by checking whether BR M1 actually conflicts with your circumstances.

If this is genuinely a second job and your full allowance is already being used elsewhere, the code may be correct.

If it appears on your only or main job unexpectedly, investigate further.

A sensible process is:

Check your payslip and confirm the exact code displayed.
Check your other employment or pension sources to see where your Personal Allowance is being used.
Give your employer your P45 if it has not already been processed.
Check whether an old employment is still active on your tax record.
Review your estimated annual income for each PAYE source.
Correct inaccurate employment or income information where necessary.
Check the following payslips once a replacement code has been issued.

You can use HMRC’s service to update your tax code if the information being used is wrong.

HMRC says that after an online correction, it will tell both you and your employer about the new code within 15 working days.

Will BR M1 Automatically Disappear in the New Tax Year?

The answer is more nuanced than simply saying temporary codes automatically continue or disappear.

For 2026/27, HMRC instructed employers to carry forward an employee’s authorised tax code where no new code was issued.

However, employers were specifically told not to carry forward Week 1 or Month 1 markings into the new tax year.

That means the M1 part should not simply be copied across at the annual rollover.

The underlying BR code may still remain where it continues to be the authorised code.

This is particularly important because the Personal Allowance did not increase for 2026/27. It remains £12,570, so there was no general Personal Allowance uplift requiring everyone’s code to change.

Can Side-Hustle Income Cause a BR M1 Tax Code?

Not automatically.

There is now greater reporting of seller information from certain digital platforms, and people earning taxable income through online marketplaces, social media or other platforms may need to report that income.

However, platform reporting itself does not mean HMRC automatically gives someone BR M1.

The treatment depends on what type of income it is.

A second PAYE job can affect how HMRC allocates allowances and may lead to BR being used on one employment.

By contrast, self-employment or trading income may need to be dealt with through Self Assessment or, where applicable, Making Tax Digital rather than through a BR M1 employment code.

The key distinction is between another PAYE employment and non-PAYE side income.

Why Can BR M1 Appear on Pension Income?

Pensions are another important situation where emergency or non-cumulative taxation can appear.

Where someone begins receiving pension payments, the pension provider operates PAYE in much the same way an employer does.

Flexible withdrawals can create particular problems.

If a pension provider makes a first flexible-access payment and does not have an appropriate tax code, HMRC’s rules can require the taxable part to be processed using an emergency code on a Week 1 or Month 1 basis.

This can produce a large initial tax deduction, especially from a one-off withdrawal.

Possible repayment routes include:

P55: Generally where only part of the pension pot has been flexibly accessed.
P53Z: Generally where the whole pot has been taken and the taxpayer has other PAYE income.
P50Z: Generally where the whole pot has been taken and there is no continuing PAYE income apart from circumstances such as State Pension.

HMRC can also review the position after the tax year if no in-year repayment claim is made.

Will You Get BR M1 Overpaid Tax Back Automatically?

BR M1 Overpaid Tax

Sometimes.

If HMRC corrects the code during the tax year and replaces an emergency or temporary treatment with an appropriate cumulative code, payroll may be able to repay overpaid PAYE through a later wage or pension payment.

HMRC specifically states that a corrected code can result in previous overpayments being repaid through pay in qualifying new-job situations.

However, an automatic immediate repayment is not guaranteed in every case.

It may depend on:

Whether HMRC has complete employment information.
Whether the replacement code is cumulative.
Whether the employment continues.
Whether the tax year has already ended.
Whether the overpayment arose from a flexible pension withdrawal.
Whether a specific repayment claim is required.

Someone who believes excess PAYE has already been deducted may also need to check whether HMRC owes a tax rebate.

Why Is It Important to Check BR M1 Rather Than Ignore It?

BR M1 is not automatically evidence of an error, but ignoring an unexpected code can allow incorrect deductions to continue.

A particularly important practical warning from consumer finance expert Martin Lewis is:

“It is your responsibility to check your tax code is correct, not your employer’s or HMRC’s.”

The underlying point is sound: employees should look at the code shown on their payslip rather than assume payroll has enough information to identify every problem.

HMRC’s own employment guidance similarly tells workers to check their first payslip and states that individuals are responsible for making sure they are paying the right amount of tax.

What Should You Check on a BR M1 Payslip?

If BR M1 appears unexpectedly, check the whole PAYE picture rather than focusing only on the letters.

Review:

Tax Code: Does it actually show BR M1, BR, M1 or something else?
Gross Pay: Is the taxable pay figure correct?
PAYE Deduction: Does it broadly correspond with the code?
Previous Employment: Has an old job ended correctly?
Other Jobs: Which employment currently uses your allowance?
Pension Income: Has a new pension recently started?
P45: Was it supplied and processed?
Starter Information: Was the correct employment declaration made?
HMRC Record: Are all current and former employers listed correctly?

The related 1257L M1 rules are particularly useful when the issue is Month 1 treatment rather than BR itself.

How Does BR M1 Compare With Other Common Tax Codes?

Tax code	Broad meaning
1257L	Standard Personal Allowance for many employees
1257L M1	Standard allowance, but Month 1 non-cumulative treatment
BR	All income from that source taxed at basic rate
BR M1	Basic-rate taxation plus Month 1 treatment
D0	All income from that source taxed at higher rate
D1	All income from that source taxed at additional rate
0T	No Personal Allowance; normal tax bands apply
W1	Week 1 non-cumulative treatment
NONCUM	Non-cumulative payroll treatment

The crucial distinction is that BR determines the rate applied to that particular source, while M1 determines the calculation basis.

That makes BR M1 fundamentally different from codes such as 1257L M1 or 0T M1.

FAQs About BR M1 Tax Code

Is BR M1 a bad tax code?

Not necessarily. It can be correct for a second job or pension, but it should be checked if it appears unexpectedly on your main or only income.

Does BR M1 give you a Personal Allowance?

No. BR normally taxes all income from that particular job or pension at the basic rate, while M1 applies the calculation on a non-cumulative Month 1 basis.

Will BR M1 correct itself automatically?

Sometimes HMRC updates the code after receiving complete employment information, but you should not rely on this if the code appears wrong. Check your PAYE record and update incorrect details promptly.

Can BR M1 cause a tax refund?

Yes. If BR M1 resulted in too much PAYE being deducted and HMRC later issues the correct cumulative code, some overpaid tax may be repaid through payroll.

Can my employer remove BR M1?

Your employer cannot simply choose a different tax code because you request it. Payroll normally has to use the code supplied by HMRC until a replacement coding instruction is received.

What should I do if BR M1 appears on my only job?

Check your payslip, P45, starter information and HMRC employment record. If your Personal Allowance should be attached to that job, update any incorrect information with HMRC so the code can be reviewed.