The payment on account deadline is almost here. How to pay self assessment fast so it lands in time, and what to do if you cannot pay the full amount.
If it is the last day or two before 31 July and you still need to pay self assessment, this is the practical version: how to get the money to HMRC fast enough to count, and what to do if the full amount simply is not there. No history lesson, just the moves that matter with the clock running.
The 31 July deadline is your second payment on account, an advance instalment towards your tax bill equal to half of what you owed last year. Miss it and HMRC starts charging interest from the next day, so the aim over the next 48 hours is simple: pay in a way that lands on time, against the right reference.
Your second payment on account is due by midnight on 31 July. It is normally half of last year’s income tax and Class 4 National Insurance. The exact figure is in your HMRC online account under Self Assessment, and it is the number you should work from, not a guess or a rough memory of last year.
If money is tight and you are tempted to reduce the payment to make it fit, be careful. You can ask HMRC to reduce a payment on account, but only do it if your income genuinely dropped this year. Reducing it in a panic, below what you actually owe, just means HMRC charges interest on the shortfall later. There is a fuller guide on the pre-payment checklist if you have time for it.
With a day or two to go, the method matters as much as the money. These reach HMRC quickly enough to count:
These will not clear in time, so do not rely on them now:
If you are paying at a weekend, stick to Faster Payments through your banking app. It keeps working when card processing and slower methods might not settle until the next working day.
Speed is wasted if the money cannot be matched to you. When you pay self assessment, the reference is your 10-digit Unique Taxpayer Reference followed by the letter K, with no spaces, like 1234567890K.
A wrong or missing reference is the most common reason a payment does not show against your account, and sorting that out afterwards takes far longer than getting it right first time. Copy it carefully from your HMRC account, paste it into the reference field, and check it before you confirm.
Then take a screenshot of the confirmation. If HMRC ever queries whether you paid, that timestamped record settles it in seconds.
The rule is that your payment has to reach HMRC by midnight on 31 July, not simply be sent by then. That is why Faster Payments and debit card are safe on the actual day, because they arrive almost immediately, while a cheque or a first-time Direct Debit is not, because it clears later.
If you pay by Faster Payments on the evening of the deadline, you are fine. If you post a cheque on the deadline, you are late, even though you technically sent it on time. When in doubt, use your banking app.
Tom is a self-employed electrician. On the evening of 30 July he remembers his payment on account and logs in to his HMRC account. It shows £1,850 due by 31 July. He has had a normal year, so he does not try to reduce it.
He opens his banking app, sets up a payment to HMRC’s Self Assessment bank details, types the amount, and puts his UTR followed by K in the reference. Because it goes by Faster Payments, it leaves his account and reaches HMRC within minutes. He screenshots the confirmation and closes the laptop. The whole thing took under ten minutes, on the night before the deadline, and it counted as on time because the money actually arrived, not just because he pressed send.
The only thing that would have tripped him up is method. If Tom had tried to start a Direct Debit that evening, it would not have cleared for about five working days and he would have been late.
This is the part people avoid, and avoiding it is the expensive choice. If the full payment is not there, do two things.
First, pay what you can before midnight on 31 July. Interest is only charged on the amount still outstanding, so even a partial payment reduces the cost of being late.
Second, set up a Time to Pay arrangement with HMRC, which lets you spread the remaining balance over monthly instalments. You can often arrange it online through your Self Assessment account if the amount is within the usual limits, or by phone. The guide on Time to Pay for payments on account walks through how it works and what HMRC will ask.
The reassuring part is that a payment on account is a payment, not a return, so there is no separate late filing penalty for missing it. The cost of being late is interest, which builds daily from 1 August on whatever is unpaid. That is a reason to act, not to panic: paying something, and arranging the rest, is always better than silence.
Nothing about the deadline itself changed for 2026. The second payment on account is still due 31 July, still normally half of last year’s income tax and Class 4 National Insurance, and interest still runs from the day after. The £1,000 threshold that decides whether you make payments on account at all is also unchanged.
What is different for many people is that everything now lives in the HMRC online account: the figure due, the bank details to pay to, your payment history, and the option to set up Time to Pay. If you have not logged in for a while, that single login is where this whole task starts and ends.
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Online or telephone banking using Faster Payments is the fastest, usually reaching HMRC the same day or even within a couple of hours. Paying by debit card through your HMRC online account is also quick, normally clearing the same or next working day. Avoid setting up a new Direct Debit this close to the deadline, because the first one takes about five working days.
Your payment has to reach HMRC by midnight on 31 July, not just be sent by then. Faster Payments and debit card payments are near-instant, so they are safe on the day. A cheque is only treated as paid when it arrives, and a first-time Direct Debit will not clear in time, so neither is suitable at the last minute.
Do not ignore it. Pay whatever you can before the deadline to cut the interest, then set up a Time to Pay arrangement with HMRC to spread the rest over monthly instalments. Because a payment on account is a payment and not a return, there is no separate late filing penalty, but interest does build from 1 August.
There is no late filing penalty on a payment on account, because it is a payment rather than a tax return. HMRC does charge daily interest on the amount outstanding from the day after the deadline, so the cost of being late is interest, not a fixed fine. Paying part of it still reduces what the interest is charged on.
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NetPay UK works out your real net pay after tax, NI, pension and salary sacrifice, for hourly, shift and variable-income workers. Free to download.
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A note on financial advice: NetPay UK calculates take-home pay based on official HMRC tax rules. This article reflects rules in force at the time of publication (30 July 2026). Tax rules change. For complex situations, consult a qualified UK accountant or visit gov.uk/income-tax.
