His Majesty’s Revenue and Customs (HMRC) has issued a tax warning to anyone who has earned more than £1,000 from a so-called "side hustle".

If you receive money from an online marketplace or social media - such as eBay, Vinted, AirBnB, or Facebook Marketplace - you may need to inform HMRC about your income.

Everyone in the UK has a tax-free trading allowance of £1,000 additional income outside of their regular employment, so if you earn less than this amount from your side hustle in a tax year you don’t need to tell HMRC.

But those that earn more than the £1,000 threshold must declare this by registering as self-employed via HMRC and submitting a Self Assessment tax return.

In a reminder on social media platform X (formerly Twitter), HMRC said: “You might need to do a tax return if you: Have earned more than £1,000 through a side-hustle, are a self-employed delivery driver/rider, rent out a property, create online content. Check if you need to register.”

If you regularly sell goods or provide a service through an online platform, HMRC recommends that you check the guidance about selling online and paying taxes on GOV.UK.

A link is also available on the HMRC app in the ‘news’ section under the ‘communication’ tab to help you decide if your activity should be treated as a trade and if you need to complete a Self Assessment tax return.

Once you’ve registered for Self Assessment, you must send your tax return to HMRC by the deadline of January 31, 2025 or you’ll be hit with a penalty.

You must pay a late filing fine of £100 if your tax return is up to three months late and this fee can increase even further if it’s later, or if you pay your tax bill late. You’ll also be charged interest on late payments.

You can appeal against a penalty if you have a reasonable excuse that stopped you from meeting the deadline, which can include any of the following:

• your partner or another close relative died shortly before the tax return or payment deadline

• you had an unexpected stay in hospital that prevented you from dealing with your tax affairs

• you had a serious or life-threatening illness

• your computer or software failed just before or while you were preparing your online return

• service issues with HMRC online services

• a fire, flood or theft prevented you from completing your tax return

• postal delays that you could not have predicted

• delays related to a disability or mental illness you have

• you were unaware of or misunderstood your legal obligation

• you relied on someone else to send your return and they did not

HMRC says you must send your tax return or payment as soon as possible after your reasonable excuse is resolved. You cannot blame a cheque being bounced or a failed payment for missing the deadline, or say you submitted it late because HMRC didn’t send you a reminder.

Anyone unable to pay their tax bill in full by the January deadline can spread the cost using HMRC’s online ‘Time to Pay’ system, but you must file your Self Assessment tax return before setting this up.

Myrtle Lloyd, HMRC’s director general for customer services, said: “We’re here to help customers get their tax right and if you are worried about how to pay your Self Assessment bill, help and support is available.

“Customers can set up their online payment plan to suit their own financial circumstances and can spread those payments across a maximum of 12 months. It is a valuable option for someone needing extra flexibility in meeting their tax obligations.”