Self Assessment Payments
How to pay your Self Assessment bill, what payment on account means, and what to do if you cannot pay on time.
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How do you actually pay a Self Assessment bill?
Fastest: bank transfer using the HMRC account details and your UTR followed by K as the reference — Faster Payments usually arrive same day. Also solid: debit card online, or Direct Debit from your tax account, set up well before the deadline because the first one takes days to establish. At a bank branch works with a paying-in slip. Personal credit cards are not accepted.
The reference matters as much as the money. A payment with the wrong UTR reference sits unallocated while your account shows a debt — same cash, wrong pocket.
The deadline is about cleared funds
Payment must reach HMRC by 31 January (and 31 July for the second payment on account). Interest runs daily from the day after, automatically, and from 30 days late a percentage surcharge joins it. There is no grace period hiding anywhere.
If the money is there, pay a few days early and remove the mechanics from the risk. If it is not there, the next section is the one that matters.
Can't pay in full? File anyway, then arrange
Filing and paying are separate obligations with separate penalties. Filing on time kills the filing penalty even if you cannot pay a pound — never hold the return hostage to the payment.
Then set up Time to Pay: smaller balances can usually be arranged online in your tax account in minutes; larger ones mean a call to HMRC with a realistic proposal. Instalments still carry interest, but surcharges stop escalating once an arrangement is in place and kept.
Managing the July payment
The 31 July payment on account is the one that surprises people, arriving mid-year with no return attached. If this year's income is genuinely running below last year's, payments on account can be reduced — but reduce too far and HMRC charges interest on the shortfall.
This is a forecasting question, which is why our clients' Portfolio Reporting Pack numbers make it an informed adjustment rather than a hopeful one.
Frequently asked questions
What reference do I use when paying HMRC?
Your ten-digit UTR followed by the letter K, no spaces. It is what ties the payment to your Self Assessment account — a transfer without it can take weeks to trace and allocate.
Can I pay my tax bill by credit card?
Personal credit cards are not accepted. Corporate cards work with a fee, and the practical alternatives are bank transfer, debit card, or Direct Debit. If the plan was credit because the cash is short, a Time to Pay arrangement is usually the cheaper borrowing.
How quickly does a bank transfer reach HMRC?
Faster Payments: typically same day or next, including weekends. Bacs: around three working days. On deadline day, Faster Payments is the only transfer method that reliably lands in time — check your bank's limits before relying on it.
Does Time to Pay hurt my credit record or future dealings?
It is not reported to credit agencies, and a kept arrangement is a neutral fact. What matters to HMRC is the pattern: propose something realistic, keep to it, and file everything on time while it runs. A broken arrangement is worse than a slower honest one.