GigKiln

    The 31 July tax bill nobody warned you about

    By GigKiln ·

    You filed your tax return in January. You paid what you owed. You moved on. Then a reminder lands: HMRC wants another payment by 31 July, and you did not file anything to trigger it.

    That payment is called the second payment on account. It is not a new tax, not a penalty, and not a mistake. It is the second half of an advance HMRC already asked you for back in January, put towards next year's bill. For a lot of couriers, drivers and freelancers it is the most confusing bill of the year, because it turns up with no return attached to explain it.

    Here is the point. If your gig income has held steady, this is just tax you owe early, and you should pay it. If your income has dropped, you may be handing over more than you need to, and you can do something about it. The job before Friday 31 July 2026 is knowing which of those two situations you are in.

    The short version

    • The second payment on account is due by midnight on Friday 31 July 2026. It is half of last year's tax bill, paid in advance towards this year's.
    • It is not a new or extra tax. It covers your Income Tax and your Class 4 National Insurance, billed early in two halves. The first half was due on 31 January.
    • You only have payments on account if last year's tax bill was £1,000 or more and less than 80% of your tax was collected at source.
    • If you expect to earn less this year, you can reduce both payments through your Self Assessment account or form SA303. Do not over-reduce, because HMRC charges interest on any shortfall.
    • Miss 31 July and interest runs from 1 August at 7.75% a year. If you cannot pay, ask HMRC about a Time to Pay arrangement rather than going quiet.

    What the 31 July payment on account actually is

    A payment on account is an advance payment towards your next Self Assessment tax bill. HMRC collects it in two instalments. The first is due by midnight on 31 January, alongside your tax return. The second is due by midnight on 31 July. You can see both dates on the Self Assessment deadlines. Each instalment is half of the tax you owed for the previous year.

    So if last year's tax bill came to £2,000, HMRC assumes you will owe roughly the same again and asks for it in two £1,000 chunks, one in January and one in July. The July payment is that second chunk. It covers your Income Tax and, because you are self-employed, your Class 4 National Insurance.

    Why the July one stings more than January

    The January payment is easier to stomach because it arrives with your tax return. You can see the maths. The July payment arrives on its own. No return, no fresh calculation, just a demand for money on income you may not have earned yet.

    That is the part that feels unfair, and it is worth being honest about. You are paying tax in advance, on the assumption this year looks like last year. In gig work, where a strong month and a dead month can look nothing alike, that assumption is often wrong. It is not a scam, but it is a cashflow trap if nobody told you it was coming.

    Do you even have to pay it

    You do not have to make payments on account if either of these is true:

    • the tax you owed last year was less than £1,000
    • you paid more than 80% of last year's tax at source, for example through PAYE on an employed job

    If neither applies, payments on account are automatic. You do not opt in. HMRC sets them up the first time your bill crosses the threshold, which is exactly why so many people meet them by surprise in their second year of self-employment.

    The lever most gig workers miss: you can reduce it

    Here is what the reminder letter does not put in bold. If you expect to earn less this year than last, you can ask HMRC to reduce your payments on account.

    You do it through your online Self Assessment account, or by sending form SA303. You tell HMRC what you realistically expect to owe, and they lower both instalments to match. Not sure where you stand? You can estimate what you'll owe before you decide.

    This matters for gig workers because your income is not a flat line. If you have cut your hours, switched platforms, taken time off, or simply had a slower year, you should not be taxed as if last year repeats exactly.

    There is a catch, and it is the reason not to reduce it just to get through a tight month. If you reduce your payments too far and it turns out you did owe the money, HMRC charges interest on the shortfall, backdated to the original due dates. So reduce it because your income genuinely fell, not because July is an awkward time to pay. Base the new figure on what you honestly expect to earn, not on what you wish the bill was.

    What happens if you miss 31 July

    Miss the deadline and HMRC charges interest from 1 August until you pay. The late-payment interest rate is 7.75% a year as of 9 January 2026. It is set at the Bank of England base rate plus 4%, so it moves whenever the base rate moves.

    Interest runs daily, so a payment that is weeks late costs more than one that is days late. If you cannot pay in full, the better move is to pay what you can and ask HMRC about a Time to Pay arrangement, rather than going quiet and letting it build.

    Common questions

    Is the second payment on account a new tax?

    No. It is an advance towards your next tax bill, split into two payments. The July payment is the second half of what HMRC already estimated you would owe this year. You are not being taxed twice, you are paying next year's tax early.

    How is my payment on account worked out?

    Each payment is half of your total tax bill from last year, including your Class 4 National Insurance. So if last year's bill was £2,000, each payment on account is £1,000, one due 31 January and one due 31 July.

    Can I reduce my July payment on account?

    Yes, if you genuinely expect to earn less this year than last. You can lower both payments through your online Self Assessment account or by filing form SA303. Only reduce it to match what you realistically expect to owe, because HMRC charges interest on any amount you underpay.

    What happens if I pay late or cannot pay?

    HMRC charges interest from 1 August until the payment clears, currently 7.75% a year, and it builds up daily. If you cannot pay in full, pay what you can rather than nothing, and ask HMRC about a Time to Pay arrangement before the deadline rather than after.

    Do I have to make payments on account every year?

    Only while your bill is big enough to trigger them. If your tax owed drops below £1,000, or most of your tax gets collected at source through PAYE, HMRC stops asking. They start automatically the first time your bill crosses the threshold, which is why so many people meet them by surprise in their second year.

    The bottom line

    The 31 July payment on account is not a trap and not a bonus tax. It is next year's tax, paid early, in two halves. If your gig income is steady, budget for it and pay it on time. If your income has fallen, check whether you can reduce it before you hand over money you may not owe. Either way, the worst version of this is finding out it exists on 30 July. Our full guide to payments on account walks through the numbers and the reduction process in detail.

    New to all this? If you have not registered as self-employed yet, or you are still piecing together how Self Assessment fits together, start with registering as self-employed. It covers the whole setup, from your UTR to your first return, so that payments on account stop appearing out of nowhere.

    This is general guidance, not personal tax advice. Your own figures and circumstances decide what you owe, so check your Self Assessment account or speak to HMRC if anything here does not match your situation.