Starting or changing jobs

Providing the right information when you start a new job helps ensure your tax code is correct from the first pay day and avoids the risk of paying too much tax.

When starting a new job or taking on additional employment, your new employer will usually send your income details to HMRC, which are used to calculate your tax code. If this information is not provided in time, or you choose not to share it, you may be placed on a temporary emergency tax code.

To avoid this, you should provide your new employer with your P45. If you do not have a P45 or do not wish to supply it to your new employer then you should complete HMRC’s starter checklist.

You can check your employment details via HMRC’s online services or mobile app, ensuring only one employer is using the standard 1257L tax code and that your estimated income is accurate. This should be available to view within 6 weeks after your first pay day.

If your records are incorrect or incomplete, you can update your employer details, add or remove employers and amend your estimated income or benefit information directly with HMRC. These updates can help prevent underpayment or overpayment of tax.

These changes may or may not affect your tax code. If the changes result in a change, HMRC will notify your employer.

Source:HM Revenue & Customs | 05-01-2026
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Aitch
I'm Aitch, the Founder and CEO of CIGMA Accounting Ltd. As a Chartered Management Accountant and as a CIMA member, I've spent more than 16 years helping businesses, entrepreneurs, landlords, and individuals with tax planning, accounting, and HMRC compliance. As a chartered accountant in London, I'm passionate about making complex tax matters easier to understand and helping clients make confident financial decisions. Over the years, I've advised start-ups, SMEs, established companies, and high-net-worth individuals across a wide range of tax and accounting matters. My expertise includes Corporation Tax, Self-Assessment, Capital Gains Tax, Inheritance Tax planning, R&D tax relief, capital allowances, international tax, and resolving complex HMRC compliance issues. Whether clients need a business accountant, tax accountant, or strategic tax advisor, my focus is always on delivering practical advice that creates long-term value. One of my specialist areas is Making Tax Digital (MTD). I've worked extensively with businesses preparing HMRC's digital reporting requirements, helping them move to cloud accounting, improve financial processes, and adopt technology that makes compliance more efficient. I regularly speak at Making Tax Digital roadshows, industry events, and educational sessions in collaboration with Zoho Books, sharing practical insights into digital accounting, tax legislation, and the future of the profession. Many business owners looking for the best accounting firm in London are not simply searching for an accountant they're looking for trusted advice, responsive support, and long-term value. That's the approach I've taken in building CIGMA Accounting. My team and I work closely with businesses across London and the UK, providing accounting services, tax advisory, bookkeeping, payroll, VAT, company accounts, and strategic tax planning tailored to each client's goals. Through this website, I share practical guidance on UK taxation, Making Tax Digital, HMRC updates, Corporation Tax, Self-Assessment, and business finance. My aim is to provide reliable, straightforward information that helps business owners understand changing regulations, reduce compliance risks, and make informed financial decisions with confidence.