UK Self Assessment Late Filing & Payment Penalty Calculator
See HMRC's full £100 → £10/day → 5% / £300 filing ladder plus the 30-day / 6-month / 12-month payment surcharges and late-payment interest, all in one calculation.
Penalties and interest
£0.00Filed and paid on time — nothing to pay
Late filing penalties
£0.00Return filed on time
Late payment penalties + interest
£0.00Paid on time
Deadlines are derived from the year — no need to look them up.
The payment deadline is 31 January either way.
Still not filed? Leave today's date to see where you stand now.
The date the bill is cleared in full.
The balancing payment for the year — what was still unpaid at the deadline. This is the figure the late-payment ladder, and the interest, are charged on. Enter 0 if you owe nothing; the filing penalties still apply.
The total tax the return itself would show, before deducting payments on account. The 6-month and 12-month filing penalties are 5% of this figure, not of the balancing payment. Leave blank if you make no payments on account.
The four filing penalty stages (Sch 55)
Each stage runs from the day after the filing deadline, so for the usual 31 January online deadline the dates below are fixed: 1 May, 1 August and 1 February.
- Day 1 late: £100 fixed, regardless of whether you owe tax.
- 3 months late (1 May): £10 per day for up to 90 days — another £900 maximum. HMRC must give notice before charging these.
- 6 months late (1 August): greater of £300 or 5% of the tax due.
- 12 months late (1 February): another greater-of-£300-or-5%, up to 100% of the tax if deliberate and concealed.
Three payment surcharge stages (Sch 56)
These run from the penalty date — 30 days after the payment deadline, which is 2 March for a 31 January deadline (1 March in a leap year). The second and third surcharges fall 5 and 11 months after that date.
- 30 days unpaid (2 March): 5% of the unpaid tax.
- 5 months later (2 August): another 5%.
- 11 months later (2 February): another 5%.
Interest on unpaid tax accrues daily from 1 February at the HMRC published rate — currently 7.75%, set at the Bank of England base rate + 4 percentage points since 6 April 2025. It is separate from the surcharges above and continues until the bill is paid in full. Because it is charged daily, a bill outstanding across a base-rate move is charged at each rate in turn; the calculator splits the interest by rate period rather than applying one average.
Which regime applies to you
This calculator models the Schedule 55 and 56 ladder, which is the regime for Self Assessment taxpayers who are not in Making Tax Digital for Income Tax. MTD for Income Tax is mandatory from 6 April 2026 for qualifying income over £50,000, from April 2027 over £30,000, and from April 2028 over £20,000. Taxpayers inside MTD move instead to a points-based late submission system (one point per missed deadline, £200 once four points are reached) and a different late payment structure — 3% of the tax outstanding at day 15, a further 3% at day 30, then 10% a year charged daily.
Penalties are not automatic in every case: HMRC must cancel or reduce a penalty where you had a reasonable excuse — a bereavement, serious illness or unexpected hospital stay, a fire, flood or theft, a failure of HMRC's own online service, or a delay caused by a disability — provided you file as soon as the excuse ends. Not accepted: a failed payment through lack of funds, finding the online system difficult, or not receiving a reminder. Appeals must normally be made within 30 days of the penalty notice. Reasonable excuse does not remove interest on unpaid tax.
Filing penalty ladder — how a £5,000 return grows
The filing penalties below apply to the return itself, whether or not you owe tax. The cumulative column assumes £5,000 of tax is due (so the 6- and 12-month stages take the greater of £300 or 5% — here £300 each).
| How late | Penalty added | Cumulative filing penalty |
|---|---|---|
| 1 day late | £100 fixed penalty | £100 |
| 3 months late | £10/day for up to 90 days (+£900) | £1,000 |
| 6 months late | greater of £300 or 5% of tax (+£300) | £1,300 |
| 12 months late | another greater of £300 or 5% (+£300) | £1,600 |
Even a zero-tax return reaches £1,600 after 12 months (£100 + £900 daily + £300 + £300), because the tax-geared stages floor at £300.
Worked example — filed and paid 8 months late
You owe £5,000 on your 2025-26 return and file and pay it on 30 September 2027, eight months after the 31 January 2027 deadline. Using the HMRC late-payment rate of 7.75%:
| Filing — Missed filing deadline | £100.00 |
| Filing — Daily penalties (90 days × £10) | £900.00 |
| Filing — 6 months late | £300.00 |
| Payment — 30 days unpaid — 5% surcharge | £250.00 |
| Payment — 6 months unpaid — further 5% | £250.00 |
| Interest (7.75% on £5,000 for 242 days) | £256.92 |
| Total on top of the £5,000 tax | £2,056.92 |
Filing on time (even if you cannot pay) would remove the £1,300.00 filing block entirely — the single biggest saving available, and the reason to submit the return by 31 January regardless of whether you can settle the bill. If you cannot pay, a Time to Pay arrangement set up before the first penalty date normally stops the 5% surcharges, though interest keeps running.
Frequently asked questions
How does HMRC calculate Self Assessment late filing penalties?
Four escalating stages under Finance Act 2009 Sch 55: (1) £100 fixed penalty the day after the deadline; (2) from 3 months late, £10 per day for up to 90 days — a further £900 maximum; (3) at 6 months late, the greater of £300 or 5% of the tax due; (4) at 12 months late, another greater-of-£300-or-5% layer, and up to 100% of the tax if HMRC find the failure deliberate and concealed.
How are late payment surcharges different from filing penalties?
Late payment penalties are on the unpaid balancing payment under Sch 56: 5% of the tax still unpaid 30 days after the deadline, another 5% five months later, and another 5% eleven months after that first penalty date — 15% in total if the bill sits outstanding for a year. They stack on top of filing penalties and daily interest.
Do late payments on account get the 5% surcharges?
Not in their own right — payments on account are not listed in Schedule 56, so missing the 31 January or 31 July instalment attracts interest but no surcharge of its own. The catch is that HMRC's Self Assessment manual (SAM61390) calculates the balancing-payment penalty on "the balancing payment and any unpaid payment(s) on account for that year". So a payment on account that is still outstanding when the first penalty date arrives is pulled into the 5% base rather than escaping it.
What is the current HMRC late-payment interest rate?
From 6 April 2025 the HMRC late-payment interest rate is Bank of England base rate plus 4 percentage points (previously base + 2.5%). Interest runs from the day after the payment deadline until the tax is paid in full and is charged daily on the outstanding balance. See our HMRC interest rates page for today's figure and the full rate history.
What counts as a reasonable excuse?
HMRC accept reasonable excuses such as a recent bereavement, a serious illness, an unexpected stay in hospital, a fire/flood/theft that destroyed records, postal delays outside your control, service issues with HMRC's own systems, or disability-related problems. Reasonable excuse waives filing penalties if the return is submitted without unreasonable delay once the excuse ends — it does not waive interest on unpaid tax.
Can I avoid penalties by filing but not paying?
Yes for the filing penalty ladder (£100 + daily + 5% + 5%), which is tied to the return not arriving. But you will still face the Sch 56 payment surcharges (5% / 5% / 5%) and daily interest on the unpaid tax. Setting up a Time to Pay arrangement with HMRC before the 30-day point usually prevents the first 5% surcharge.
Does the £100 fixed penalty apply if I owe no tax?
Yes. The £100 initial penalty and subsequent daily/tax-geared ladder apply to the return itself — it is triggered by being late, not by owing tax. The tax-geared stages (5% at 6 and 12 months) floor at £300 each, so even a zero-tax return can still accumulate £1,600 in filing penalties after 12 months (£100 + £900 daily + £300 + £300).
Does the Making Tax Digital points system replace these penalties?
Only for taxpayers actually inside Making Tax Digital for Income Tax — mandated from 6 April 2026 for qualifying income over £50,000, April 2027 over £30,000 and April 2028 over £20,000. Those taxpayers get a points-based late submission regime (a point per missed deadline, £200 once four points are reached) and a different late payment structure: 3% of the tax outstanding at day 15, a further 3% at day 30, then 10% a year charged daily. Everyone else — the great majority of Self Assessment filers — stays on the Schedule 55 and 56 ladder this calculator models.
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