Why Did HMRC Reduce My Personal Allowance? Explained for PAYE Employees

Seeing your Personal Allowance decrease can be unexpected, particularly if you are a PAYE employee who usually receives the standard tax-free allowance. If your tax code or take-home pay has recently changed, understanding HMRC Personal Allowance changes can help you understand why more Income Tax may now be deducted from your earnings.

For the 2026/27 tax year, the standard UK Personal Allowance is £12,570. However, the amount available to you can be reduced in certain situations, especially when your adjusted net income goes above £100,000. HMRC may also update your PAYE tax code because of taxable benefits, other income, previous tax underpayments or changes to your personal circumstances.

This guide covers the main reasons your Personal Allowance may have changed, how the reduction works and the practical steps you can take if your PAYE tax code is different.

What Does Personal Allowance Mean?

The Personal Allowance is the amount of income an individual can generally receive before Income Tax becomes payable.

For 2026/27, the standard Personal Allowance is:

£12,570 annually
£1,048 monthly
£242 weekly

These figures generally apply throughout the UK, although Scottish taxpayers are subject to different Income Tax rates and bands.

For many employees paid through PAYE, the Personal Allowance is reflected in their tax code. The commonly used standard code is 1257L, although your own code can vary depending on your circumstances.

When HMRC reduces the allowance included in your tax code, a greater proportion of your earnings may become taxable.

Why Might HMRC Reduce My Personal Allowance?

There are several possible reasons why the Personal Allowance shown in your tax information may be lower than expected.

1. Your Adjusted Net Income Is Above £100,000

One of the most significant reasons for a reduced Personal Allowance is adjusted net income above £100,000.

Once your adjusted net income exceeds £100,000, your Personal Allowance is reduced by £1 for every £2 of income above that threshold.

For 2026/27, the allowance can be reduced completely to zero once adjusted net income reaches £125,140.

For example, if your adjusted net income is £110,000:

Amount above £100,000: £10,000
Personal Allowance reduction: £5,000
Original Personal Allowance: £12,570
Remaining Personal Allowance: £7,570

As a result, another £5,000 of your income becomes subject to Income Tax.

2. Your Total Taxable Income Is More Than Your Salary

Your Personal Allowance is not determined by your basic salary alone.

Adjusted net income may include several different forms of taxable income, including:

Employment earnings
Taxable benefits from employment
Pension income
Savings income
Dividend income
Self-employment profits
Certain taxable benefits

Qualifying pension contributions and Gift Aid payments can also be relevant when calculating adjusted net income.

For instance, someone earning £95,000 from employment could potentially exceed the £100,000 adjusted net income threshold if they also receive substantial taxable benefits or other taxable income.

3. You Receive Taxable Benefits From Your Employer

Some employment benefits can increase your taxable income and therefore affect your overall tax position.

Examples can include:

Company cars
Private medical insurance
Certain employer-provided accommodation
Other taxable employment benefits

If these benefits push your adjusted net income above £100,000, they may contribute to a reduction in your Personal Allowance.

Employees receiving significant benefits should therefore check that HMRC has the correct information.

4. HMRC Is Recovering an Earlier Tax Underpayment

A change in your tax code does not necessarily mean that your Personal Allowance has been permanently reduced because of your income.

HMRC may alter your PAYE code to recover an estimated underpayment from a previous tax year.

For example, where HMRC believes that you previously paid too little tax, your current tax code may be adjusted so that additional tax is collected from your salary.

Your coding notice should normally explain the adjustments HMRC has included.

5. You Have Additional Sources of Taxable Income

HMRC may amend your PAYE code if it receives information indicating that you have taxable income in addition to your main employment.

This could include:

Income from another job
Pension income
Savings interest
Taxable employment benefits
Other taxable income

If HMRC estimates that additional tax needs to be collected through PAYE, your tax code may be adjusted accordingly.

It is therefore important to check that the income information HMRC holds is accurate and up to date.

6. HMRC Has Issued a Different Tax Code

Your tax code is used by your employer to determine how much Income Tax should generally be deducted from your pay.

HMRC may issue a revised code when your circumstances change.

Reasons can include:

A change in salary
Starting a new job
Taking a second job
Receiving taxable benefits
Receiving pension income
Previous tax underpayments
Changes to your Personal Allowance
Other information reported to HMRC

Once HMRC issues a new code, your employer will normally apply it through its payroll system.

How Does a Reduced Personal Allowance Affect Your Salary?

When your Personal Allowance is reduced, less of your income is covered by the tax-free allowance.

For example, suppose your allowance falls from £12,570 to £7,570. This represents a reduction of £5,000.

However, this does not mean that you automatically pay £5,000 more in tax. Instead, £5,000 of additional income becomes taxable.

If that additional taxable income is subject to a 40% Income Tax rate, it could result in £2,000 of additional Income Tax.

Your actual tax liability will depend on your income, tax bands and individual circumstances.

What Is Adjusted Net Income?

Adjusted net income is particularly important for people whose income is close to or above £100,000.

Broadly, it is based on total taxable income before Personal Allowances, after taking certain qualifying deductions and reliefs into account.

Depending on your circumstances, it may include:

Salary
Bonuses
Taxable benefits
Savings interest
Dividends
Pension income
Rental income
Self-employment profits

Certain qualifying pension contributions and Gift Aid donations may reduce adjusted net income.

Because the calculation can involve multiple income sources and deductions, people approaching the £100,000 threshold should carefully review what has been included.

How Can I Find Out Why My Personal Allowance Changed?

If your Personal Allowance has changed, start by reviewing your latest HMRC tax information and coding notice.

Pay particular attention to:

Your current tax code
The Personal Allowance included in the code
HMRC's estimated annual income figure
Taxable employment benefits
Other taxable income
Previous tax underpayments
Tax reliefs and deductions
Any explanation supplied by HMRC

Your P2 coding notice can be especially useful because it shows the allowances and deductions HMRC has used when determining your tax code.

You should also compare these figures with your most recent payslip.

What If HMRC Has Incorrect Information?

If you believe HMRC has used incorrect information when calculating your tax code or Personal Allowance, review the details currently held about you.

You may need to check or update information relating to:

Expected salary
Employment benefits
Pension income
Other taxable income
Employment details
Relevant tax reliefs

If HMRC subsequently changes your tax code, your employer should receive the revised information and apply it through payroll.

Where your circumstances are more complicated, professional personal tax support services can help you understand your tax position and identify information that may need to be corrected.

Understanding Your P60

Your P60 is another useful document when checking your PAYE position at the end of the tax year.

It provides a summary of your pay and deductions and can help you confirm how much you earned and how much Income Tax and National Insurance were deducted.

If you are checking your PAYE records, understanding your P60 form can help you interpret the information contained in this document.

Employers generally provide P60s to relevant employees by 31 May following the end of the tax year.

What Is a Payroll Number?

A payroll number is an internal reference used by an employer to identify an employee within its payroll system.

It is separate from your tax code and does not determine the amount of Personal Allowance you receive.

If you are reviewing your payslip following a tax-code change, it may also be helpful to understand finding your employee payroll number.

Your payroll number is mainly an employer reference, whereas your tax code helps determine PAYE Income Tax deductions.

Can Pension Contributions Affect Personal Allowance?

For individuals with adjusted net income close to £100,000, qualifying pension contributions can be relevant.

Certain pension contributions may be taken into account when calculating adjusted net income and can therefore affect the amount of Personal Allowance available.

However, pension planning involves wider tax and financial considerations. Any significant financial decision should be considered in light of your individual circumstances.

How Can You Prevent Unexpected PAYE Changes?

There are several practical ways to keep your PAYE information accurate.

Check Your Tax Code

Whenever HMRC issues a new coding notice, review the tax code and the information used to calculate it.

Review Your Estimated Income

Check that HMRC's estimate of your annual income is reasonable, particularly if your salary, bonus or other earnings have changed.

Check Employment Benefits

Review taxable benefits such as company cars and private medical insurance to ensure the information is accurate.

Keep Records of Tax Reliefs

Maintain appropriate records of qualifying pension contributions and Gift Aid donations.

Check Your Payslips

Regularly review your payslips, tax code and deductions rather than waiting until the end of the tax year to identify a potential issue.

Common Questions About a Reduced Personal Allowance

Does everyone earning over £100,000 lose their Personal Allowance?

No. The Personal Allowance is reduced gradually. For every £2 of adjusted net income above £100,000, the allowance is reduced by £1. For 2026/27, it reaches zero at £125,140.

Can my employer reduce my Personal Allowance?

Your employer normally applies the tax code provided by HMRC. HMRC determines the coding information, while your employer uses that code to calculate PAYE deductions.

Does a reduced Personal Allowance mean I will pay more tax?

It can. When a smaller amount of income is covered by your Personal Allowance, more of your income may become subject to Income Tax.

Can HMRC change my tax code during the tax year?

Yes. HMRC can issue an updated tax code when it receives new information or when your circumstances change.

Does a changed tax code mean I have made a mistake?

Not necessarily. Tax codes can change for many legitimate reasons, including changes to income, taxable benefits, allowances, deductions or previous tax underpayments.

Final Thoughts

A reduction in your Personal Allowance can affect the amount of Income Tax deducted from your salary, but a changed allowance or tax code does not automatically mean your employer has made an error.

For 2026/27, the standard Personal Allowance is £12,570, with a gradual reduction applying when adjusted net income exceeds £100,000.

The most useful step is to identify why HMRC has changed your allowance or tax code. Reviewing your coding notice, payslips, income figures, benefits and deductions can help you establish whether the information is correct.

If you need support with PAYE, tax codes, Personal Allowance calculations or other personal tax matters, Coxhinkins provides accounting and personal tax support to help individuals manage their UK tax responsibilities.