Every deadline that matters to a UK dentist for 2026/27, in one bookmark-able page. Clients never need it — we chase them first — but it's here for everyone else.
The quarterly update dates above are only live for you if you have been pulled into Making Tax Digital for Income Tax, and the entry test is a threshold applied to a tax year that has already finished. Qualifying income over £50,000 in 2024/25 meant you should have started on 6 April 2026. Over £30,000 in 2025/26 brings you in on 6 April 2027. Over £20,000 in 2026/27 brings you in on 6 April 2028.
Two things about that test catch dentists out. Qualifying income is gross trading and property income — your total associate receipts before lab fees, before superannuation, before any expense at all — so an associate with a £78,000 gross schedule and £52,000 of taxable profit is over the £50,000 line, not under it. And because the test looks backwards, the year that decides your start date is already filed by the time it matters. A locum picking up extra sessions in 2026/27 is deciding their April 2028 obligations now. Our MTD guide for dentists works through the whole mechanic, and the first quarterly update shows what actually gets submitted.
Once you are inside MTD, the familiar self assessment penalties are replaced, and the replacement is harsher at the front end and gentler at the back. Late filing moves to penalty points: one point per missed deadline, a £200 charge at four points, and another £200 for every miss after that. Points below the threshold drop off 24 months after the deadline they relate to. Quarterly updates only start earning points for tax years after 2026/27, so the four updates listed above are, in penalty terms, a practice run.
Late payment is where the change bites. Instead of nothing until day 30, tax still unpaid at 15 days attracts 3%, a further 3% is charged on anything still unpaid at 30 days, and from day 31 a second penalty accrues daily at 10% a year until the balance clears.
The practical consequence is that a time to pay arrangement is now worth far more than it used to be, and worth agreeing before day 15 rather than after the first demand lands. Knowing the January number by the previous summer is what makes that possible, which is the whole argument for filing early — see how payments on account work if the size of the January bill is the part that keeps surprising you.
The limited company deadlines above are relative, which is where they catch people out. Worked through for a 31 March 2026 year end: corporation tax is payable by 1 January 2027, the accounts must reach Companies House by 31 December 2026, and the CT600 is due by 31 March 2027. Note the order — the tax is due before the return that calculates it, which is why leaving the accounts until the filing deadline means paying an estimate or paying late.
Associates who incorporated part-way through a year get a first period that is rarely twelve months long, and every one of these dates shifts with it. Our incorporation guide covers the first-year mechanics.
Self assessment penalties are fixed and automatic. They are not negotiated down for being nearly on time.
A dentist who files a year late owing £20,000 therefore faces £100, £900, and two charges of £1,000 in filing penalties — £3,000 — plus £3,000 in late payment penalties and interest running the whole time. Roughly £6,000, before interest, for paperwork that was already prepared.
Work down in this order. If you are a self-employed associate, the self assessment block applies in full. If your qualifying income from self-employment and property was over £50,000 in 2024/25, the Making Tax Digital block applies to you from 6 April 2026 as well — that is trading and property turnover before expenses, not profit, so plenty of associates cross it without feeling wealthy. If you trade through a limited company, the company block replaces the payment dates but not your personal return. If you employ anyone directly, the employer block applies on top of everything else. Most incorporated principals are living with all four sets at once, which is precisely why the year needs a calendar rather than a memory.
More than people expect, because the filing penalties and the payment penalties run in parallel and neither is discretionary. The return itself attracts £100 the day after 31 January even if you owe nothing, then £10 a day from three months late for up to 90 days, then the higher of 5% of the tax or £300 at six months, and the same again at twelve. Separately, unpaid tax attracts 5% surcharges at 30 days, six months and twelve months, with HMRC late payment interest of 7.75% from 9 January 2026 running throughout. A dentist a year late on £20,000 is looking at roughly £6,000 before interest.
Not for 2026/27. Under the Making Tax Digital penalty regime you collect one penalty point for each missed filing deadline, and a £200 penalty once you reach four points, with a further £200 for every miss after that. Quarterly updates only start attracting points for tax years after 2026 to 2027, so the four updates due on 7 August 2026, 7 November 2026, 7 February 2027 and 7 May 2027 will not cost you points if they slip. Your annual return will. Treat this first year as the free run at building the habit, because from 2027/28 four late updates is a £200 bill.
No — the penalty structure is different and it bites much sooner. Once you are inside the Making Tax Digital regime, tax unpaid 15 days after the due date attracts 3% of the outstanding amount, another 3% is charged on whatever is still unpaid at 30 days, and from day 31 a further penalty accrues daily at 10% a year until you clear it. So a £20,000 liability left unpaid for two months costs £1,200 in penalties plus interest, where the old regime would have charged nothing until day 30. If you cannot pay in full, a time to pay arrangement agreed before day 15 stops the clock.
The mandatory Scheme Pays election deadline for a 2025/26 annual allowance charge is 31 July 2027 — the scheme settles the charge and reduces your eventual pension in exchange. The date catches dentists out because it sits eighteen months after the tax year and six months after the self assessment deadline that reports the charge, so it feels finished when it is not. It also depends on a pension savings statement you may never have been sent: NHSBSA issues one automatically only where growth exceeds the standard annual allowance in that scheme alone, and a dentist with private pension contributions or two employments can breach the limit without triggering one.
Because they are all relative to your accounting reference date, which is unique to your company, so no published calendar can print them. Three separate deadlines hang off that one date: corporation tax is payable nine months and one day after the period end, the accounts must reach Companies House at nine months, and the CT600 return is not due until twelve. The confirmation statement runs on a fourth cycle entirely, tied to your incorporation anniversary rather than your year end. Associates who incorporated mid-year also get a first accounting period that is rarely twelve months long, which shifts every one of these dates for the first cycle only.
Fixed-fee dental accounting with every date on this page handled for you, early, as standard.
One short email a month: deadlines coming up, rule changes that affect dentists, and one number worth checking in your practice. No spam, unsubscribe any time.