The onset of the new financial year on April 6 is set to usher in a slew of changes for workers, benefit claimants, and pensioners.

In preparation, HM Revenue and Customs (HMRC) is proactively sending out emails encouraging individuals to review their newly issued tax codes for the 2025/26 financial period.

A tax code is pivotal as it informs your employer or pension provider of the exact amount of tax to be subtracted from your wages.

Currently, the most common tax code is 1257L, utilised primarily by those with a single job or pension.

Despite this, news has emerged from the UK Government that the Personal Allowance will remain static at £12,570, extending this freeze which has been in place since the 2021/22 financial year, right up until the onset of the 2028/29 fiscal year.

In the advisory email from HMRC, readers are alerted to four fundamental reasons why their tax code may experience changes come April. It says: "Your PAYE Income Tax records have recently changed, which means the amount of tax you pay will change."

To maintain high levels of security, HMRC maintains a policy of withholding full details within the email itself, instead directing taxpayers to sign into their online HMRC account for comprehensive information, reports

To figure out your tax code, simply take a glance at your latest payslip.

Armed with your Personal Allowance tax code, hop over to the GOV.UK portal and whip out their nifty "Check your Income Tax for the current year" feature.

Tailored for this financial year, it's a breeze to monitor your tax code and Personal Allowance, and even spot any tweaks to your code. The website is a veritable treasure trove, offering glimpses of your potential yearly tax hit - although freelancers need not apply.

As GOV.UK says: "You cannot use this service if Self Assessment is the only way you pay Income Tax."

Deciphering tax code digits is more simple than it looks as they reveal the amount you can earn without tax - your Personal Allowance. Multiply the numbers by 10 to unveil your tax-free earnings limit.

Tax code 1257L lets you pocket £12,570 before owing a penny to the taxman. If your salary hits £30,000, you're looking at taxable income of £17,430 (£30,000 minus £12,570).

The alphabet soup that is your tax code's letters sheds light on personal details affecting Personal Allowance. For the full gamut of what these letters signify, head to the Gov.UK website.

Among the most prevalent figures you'll encounter is:

L - Signalling an employee who basks in the standard no-tax Personal Allowance.

S - This is for an employee whose primary residence is in Scotland. BR/ SBR - This applies to a second job or pension.

M - This is for an employee who has received some of their Personal Allowance from their spouse or civil partner.

N - This is for an employee who has transferred some of their Personal Allowance to their spouse or civil partner.

T - This is used when HMRC needs to review certain items with the employee.

If your tax code ends with 'W1', 'M1' or 'X'. W1 (week 1) and M1 (month 1) are emergency tax codes that appear at the end of an employee's tax code, such as '577L W1', '577L M1' or '577L X'.

If your tax code starts with a 'K'. Tax codes beginning with 'K' indicate you have income that isn't being taxed in another way and it exceeds your tax-free allowance.

This typically occurs when your employer or pension provider deducts the tax due on the untaxed income from your wages or pension, even if another organisation is paying you the untaxed income.