HMRC Tax Code Changes 2026/27: Are You Overpaying?

As we approach the 2026-27 tax year, the UK’s tax landscape is undergoing one of its most significant transformations in decades. HMRC is moving away from the old-school, annual “paper and post” mentality and fully embracing a digital-first, real-time approach. For small business owners, landlords, and the self-employed, this isn't just a minor administrative tweak: it's a fundamental change in how you interact with the taxman.

Whether you are running a thriving local business or managing a property portfolio, understanding these shifts is essential to avoid surprises in your take-home pay and, more importantly, to steer clear of the new penalty regime. In this guide, we’ll break down the three most crucial updates: the expansion of Making Tax Digital (MTD), the "real-time" tax code shake-up, and the introduction of a points-based penalty system.

1. Making Tax Digital (MTD) for Income Tax: The £50,000 Threshold

The headline change for the 2026-27 tax year is the official launch of Making Tax Digital for Income Tax Self-Assessment (MTD ITSA). While MTD for VAT has been in place for a few years, this new phase brings sole traders and landlords into the fold.

Who is affected from April 2026?

If you are a self-employed individual or a landlord with a total qualifying income of more than £50,000, you are legally required to join MTD from 6 April 2026. This "qualifying income" is your gross income (turnover) before any expenses are deducted.

What does this change for you?

Under the old system, you likely handed your records to your self-assessment accountant once a year to file a single return. Under MTD, the process becomes "always-on":

• Digital Record-Keeping: You must keep your business records digitally. This means moving away from spreadsheets or paper ledgers and using bookkeeping software that is HMRC-compatible.

• Quarterly Updates: Instead of one big annual deadline, you will submit four summary updates of your income and expenses to HMRC throughout the year.

• Final Declaration: You will still need to complete a final declaration by 31 January following the tax year to finalise your tax position.

By moving to quarterly reporting, HMRC aims to reduce the "tax gap" caused by errors, but for the business owner, it provides a much clearer view of your tax liabilities as you go, rather than waiting for a surprise bill in January. For a wider look at how businesses are adapting, see MTD is Here: How Landlords and Sole Traders are Responding in 2026.

2. The 2026-27 Tax Code Shake-Up: Improving Real-Time Accuracy

While MTD focuses on the self-employed, millions of employees and those with mixed income will notice a "shake-up" in their tax codes. HMRC is implementing more sophisticated data-matching to ensure tax codes are more accurate throughout the year.

The Removal of Outdated Reliefs

Starting in April 2026, HMRC is "cleaning" tax codes by removing outdated or unverified reliefs. If you have had flat-rate employment expenses (for example, for uniforms or professional fees) or higher-rate Gift Aid relief coded into your PAYE for years, HMRC may remove these if their data suggests they are no longer applicable.

Specifically, HMRC is looking at:

• Employment Expenses: If you haven't updated your claim or filed a return recently, expenses over £120 may be stripped from your code.

• Gift Aid: If you’ve had the same amount of relief for three years without a new Self-Assessment filing, it may be removed.

Real-Time Adjustments

The goal is "real-time" accuracy. HMRC’s systems will now more proactively estimate your total annual income based on your year-to-date earnings. If you get a bonus, a pay rise, or start a second job, your tax code may change mid-year to prevent you from underpaying tax. While this prevents a large bill at the end of the year, it can mean your take-home pay fluctuates more than you’re used to. For broader policy context around these tax changes, read The Spring Statement 2025: 3 Key Updates for UK Small Businesses.

Checking your tax code on your HMRC personal tax account is more important than ever. If you find that your code has changed and you’re unsure why, consulting with a tax preparation expert can help ensure you aren't overpaying.

3. The New Points-Based Penalty System: Replacing the £100 Automatic Charge

Perhaps the most welcome (yet misunderstood) change is the replacement of the rigid £100 automatic late-filing penalty. HMRC is moving to a "points-based" system designed to be fairer to those who make an occasional mistake while cracking down on persistent late-filers.

How the Points Work

Think of it like a driving licence, but for tax.

1. Each time you miss a submission deadline (like a quarterly MTD update or your annual return), you receive one penalty point.

2. You only receive a financial penalty once you hit a specific points threshold.

3. For those filing quarterly (MTD), the threshold is 4 points. For those filing annually, the threshold is 2 points.

4. Once you hit the threshold, you are hit with a £200 fine. Every subsequent late filing also triggers a £200 fine. You can read more about how this works in The £200 Penalty Trap: Understanding HMRC's New Points-Based System.

The "Soft Landing" for 2026-27

HMRC understands that MTD is a big leap. For the first year (2026-27), there is a "soft landing" for those with income over £50,000. While you are still required to submit your quarterly updates, you will not accrue penalty points for late quarterly updates during this first year. However, this grace period does not apply to the final end-of-year declaration due in January 2028.

How to Reset Your Points

Points don't last forever. If you are below the threshold, they typically expire after 24 months. If you have already hit the threshold and been fined, you must complete a "period of compliance": usually 12 months of on-time filing: to reset your points to zero.

Navigating the Changes with Confidence

The 2026-27 tax year represents a shift toward a more transparent, digital relationship with HMRC. While the "tax code shake-up" and MTD might seem daunting, they are designed to provide more certainty. By seeing your income and tax liabilities in real-time, you can better manage your cash flow and avoid the stress of the "January tax crunch."

However, with more frequent filing comes more opportunities for administrative errors. The new points-based system is fairer, but it rewards those who stay organised.

At Accountant Search, we specialise in matching SME businesses and landlords with the right professional help. Whether you need a limited company accountant to handle your corporate transitions or a specialist to help you migrate to MTD-compatible software, we are here to help. If you're not sure where to start, How to Find an Accountant in the UK: A Step-by-Step Guide for Business Owners offers practical guidance.

The best time to prepare for April 2026 is now. By setting up your digital records today, you can turn a "shake-up" into a step forward for your business growth.

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Author: Jessica Jessica is a senior contributor at Accountant Search, focusing on helping UK small businesses navigate the complexities of HMRC compliance and digital transformation.