Self Assessment taxpayers may need to make their second Payment on Account before the end of the month

HM Revenue & Customs (HMRC) has warned millions of Self Assessment taxpayers they have just 30 days left to meet a key payment deadline.

The second Payment on Account for the current tax year must be paid by July 31, a requirement affecting many self‑employed workers, landlords and others who complete an annual tax return.

Missing the deadline could leave taxpayers in arrears and trigger interest charges on outstanding balances.

Payments on Account are advance contributions towards the following year’s tax bill, with each instalment typically equal to half of the previous year’s Self Assessment liability.

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

However, not all Self Assessment customers are required to make these payments: they generally apply only to those who owed more than £1,000 in tax last year and whose tax was not mostly collected at source through PAYE or another method.

Taxpayers expecting a lower income this year can apply to reduce their Payments on Account, although HMRC warns that cutting them too far may result in interest charges if the final bill is higher.

Several payment options are available, including the HMRC app, online banking and payment plans that spread costs over weekly or monthly instalments.

HMRC said almost two million customers have used its app to make tax payments since its launch, with features that allow users to track payments and set deadline reminders.

Myrtle Lloyd, HMRC’s Chief Customer Officer, said: “We know managing a Self Assessment tax bill isn’t always straightforward and we are here to help.

"From paying instantly via the HMRC app to spreading the cost through a payment plan, there’s support available for every customer."

From mid‑July, around 300,000 people who pay the High Income Child Benefit Charge will have their Child Benefit information automatically added to their online tax returns, making the process quicker and easier.

New rules have also come into force for higher earners: sole traders and landlords with annual income above £50,000 must now comply with Making Tax Digital for Income Tax, with their first quarterly submission due by August 7.

The department is also urging taxpayers to keep their contact details up to date and remain alert to scams.

HMRC said genuine communications will never ask customers to disclose sign‑in details or click unexpected links in emails or text messages.