Taxpayers warned as April 6 HMRC tax code changes comes into force | Personal Finance | Finance

Taxpayers across the UK are being urged to check their tax codes carefully as new rules introduced by HM Revenue and Customs (HMRC) come into force from today (April 6 2026), potentially affecting take-home pay for millions.

From the start of the 2026–27 tax year, HMRC will automatically remove certain reliefs from PAYE tax codes where it believes they are no longer accurate or relevant. The changes focus on employment expenses and higher-rate Gift Aid relief, both of which have historically been included in tax codes to reduce the amount of tax deducted from wages.

Under the new approach, employment expenses exceeding £120 may be removed where HMRC data indicates a change in circumstances.

This could apply where an individual no longer has PAYE income, where there has been a full tax-year gap in employment since the expense was first claimed, or where a taxpayer has not submitted a Self Assessment return since the 2021–22 tax year despite signals that one should have been filed.

Adjustments may also be made where the level of expenses in a tax code is higher than that reported in a 2022–23 Self Assessment return.

Higher-rate Gift Aid relief will also be removed from tax codes in cases where the same level of relief has been applied for at least three years and no Self Assessment return has been submitted over that period.

HMRC says this is intended to prevent outdated estimates of charitable donations from continuing to reduce tax liabilities without being reviewed.

The changes will be applied automatically using information already held by HMRC, meaning some taxpayers may see adjustments without having taken any direct action.

As a result, individuals could notice changes to their tax code and, in some cases, an increase in the amount of tax deducted from their salary.

HMRC has said that anyone who believes their tax code has been amended incorrectly will be able to submit a claim or update their details through its online service.

Tax specialists are advising workers to review their tax codes at the start of the new tax year to ensure any reliefs they are entitled to remain in place.

The move forms part of a wider effort by HMRC to ensure PAYE tax codes better reflect real-time taxpayer circumstances, but it also increases the importance of keeping personal tax information up to date to avoid unexpected changes in take-home pay.