HMRC's 31 July Tax Deadline: What Every Business Owner Needs to Know

One overlooked deadline could cost you hundreds in unnecessary interest and penalties.

For many business owners, July is associated with summer holidays, quieter trading periods and planning for the second half of the year. However, there's one date that should already be in your diary: 31 July.

If you're self-employed, a landlord, a company director with untaxed income or someone who completes a Self Assessment tax return, this deadline could have a significant impact on your finances.

Missing it doesn't just mean paying late. It can also lead to interest charges, additional costs and unnecessary stress.

Here's everything you need to know.

What Happens on 31 July?

The 31 July deadline is when many taxpayers must make their second Payment on Account towards their next Self Assessment tax bill.

Payments on Account are advance payments made towards your future tax liability. Rather than paying your entire tax bill in one go, HMRC asks many taxpayers to spread the cost across two instalments each year.

The first payment is usually due on 31 January, with the second due on 31 July.

Who Needs to Make a Payment?

You may need to make a Payment on Account if you:

• Are self-employed.

• Receive income from property or rental investments.

• Are a partner in a partnership.

• Have significant untaxed income.

• Pay tax through Self Assessment and your previous tax bill met HMRC's criteria for advance payments.

If you're unsure whether you need to pay, it's important to check your HMRC online account or speak to your accountant well before the deadline.

What Happens If You Miss the Deadline?

Missing the 31 July payment doesn't usually trigger an immediate penalty, but HMRC will begin charging late payment interest on any outstanding amount from the day after the deadline.

If the debt remains unpaid, additional charges can accumulate over time, increasing the overall cost.

Paying on time is often the simplest way to avoid unnecessary expenses and maintain healthy cashflow.

Common Mistakes We See

Every year, businesses and individuals make avoidable mistakes that result in unexpected tax bills or unnecessary interest.

Some of the most common include:

• Assuming no payment is due because a tax return has already been submitted.

• Forgetting that Payments on Account are separate from filing deadlines.

• Not budgeting for advance tax payments throughout the year.

• Waiting until the final few days to review HMRC correspondence.

• Overlooking changes in income that could affect future tax liabilities.

A little preparation can prevent last-minute surprises.

How to Check If You Need to Pay

You can usually confirm whether a Payment on Account is due by:

• Logging into your HMRC online Self Assessment account.

• Reviewing your latest Self Assessment calculation.

• Checking recent correspondence from HMRC.

• Contacting your accountant for confirmation.

If your income has reduced significantly since your last tax return, you may also be able to apply to reduce your Payments on Account. However, it's important to do this carefully, as reducing payments incorrectly could result in additional interest if too little tax is paid.

Why Cashflow Planning Matters

One of the biggest challenges for growing businesses isn't profitability—it's timing.

Unexpected tax payments can place unnecessary pressure on working capital, particularly during quieter trading periods or when customers are taking longer to pay invoices.

Regular cashflow forecasting allows you to:

• Set aside funds for upcoming tax liabilities.

• Avoid last-minute borrowing.

• Make informed investment decisions.

• Reduce financial stress throughout the year.

• Keep your business operating smoothly.

Tax deadlines should never come as a surprise.

How Zyla Can Help

Managing tax deadlines is about more than staying compliant. It's about giving you confidence to focus on running your business.

At Zyla Accountants, we help business owners stay ahead of important HMRC deadlines through proactive tax planning, digital accounting systems and practical financial advice.

Whether you need support with Self Assessment, company accounts, tax planning or improving your cashflow, our team is here to help.

Don't Leave It Until the Last Minute

If you're unsure whether a Payment on Account is due, or you'd like advice on managing your tax obligations more efficiently, now is the perfect time to review your position.

Getting ahead of the 31 July deadline today could save you time, money and unnecessary stress tomorrow. Contact us today for support with your business finances.