Stamp Duty Penalty Calculator: Late Filing, Late Payment and Interest
Work out what a missed SDLT deadline actually costs, broken down by each statutory charge.
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What clients say
The tax itself, not the property price.
Normally completion day.
Leave as today if still unpaid.
Your deadline was 26 April 2026, 14 days after the effective date.
130 days late.
| Charge | Basis | Amount |
|---|---|---|
| Late filing penalty | FA 2003 Sch 10 | £200 |
| 5% of the unpaid tax, 30 days late | FA 2009 Sch 56 | £250 |
| Interest on the unpaid tax | Base rate + 4pp, currently 7.75% | £138 |
| Total on top of the SDLT | £588 | |
England and Northern Ireland only. Interest is simple, not compounded, and runs from the day after the deadline at the Bank of England base rate plus 4 percentage points, 7.75% since 9 January 2026. Scotland and Wales set their own deadlines, penalty tiers and interest rate.
Three Charges, Not One
A late SDLT return produces separate charges under separate pieces of legislation, and they run at the same time rather than instead of one another. Treating them as a single "penalty" is the most common reason people underestimate the bill.
| Charge | Triggered by | Authority |
|---|---|---|
| Late filing penalty | Filing the return after the deadline | FA 2003 Sch 10 |
| Late payment penalty | Paying the tax after the deadline | FA 2009 Sch 56 |
| Interest | The tax being outstanding, day by day | Base rate + 4pp |
A fourth regime exists for inaccurate returns under FA 2007 Sch 24, running from 30% for careless errors to 100% for deliberate and concealed ones. It is behaviour-based rather than time-based, so it is not modelled by this calculator.
Late Filing Penalties
The fixed penalty for filing an SDLT return late is £100 where the return is up to three months late, and £200 where it is more than three months late. Once the return is twelve months late, HMRC can add a tax-geared penalty of up to 100% of the tax due.
There is no £300 tier and no £10 daily penalty for SDLT. Those belong to Revenue Scotland, the Welsh Revenue Authority and ATED, which is why they turn up so often in search results for stamp duty penalties. Applying them to an England or Northern Ireland transaction will overstate the bill.
Late Payment Penalties
Paying late is charged separately from filing late, in three tranches of 5% of the tax still unpaid at each point: at 30 days, at six months and at twelve months. On £20,000 of SDLT left unpaid for over a year, that is £1,000 at each stage, £3,000 in total, before the filing penalty and before interest.
Because each tranche bites on the tax still outstanding, paying part of the bill reduces the tranches that have not yet fallen due. Paying something is materially better than paying nothing.
How Interest Is Calculated
Interest runs on the unpaid tax from the day after the 14-day deadline until the day the tax reaches HMRC. The rate is the Bank of England base rate plus 4 percentage points, which has been 7.75% since 9 January 2026. Interest is simple rather than compounded, so it does not accelerate the longer it runs.
Interest is not a penalty. It is charged as compensation for the delay, which is why it is not normally cancelled even where an appeal against a penalty succeeds.
Worked Example
A buyer completes on 12 April 2026 with £5,000 of SDLT due. The deadline is 26 April 2026. The return is filed and the tax paid on 26 April 2027, a year late.
| Charge | Amount |
|---|---|
| Late filing penalty, more than 3 months late | £200.00 |
| Late payment, 5% at 30 days | £250.00 |
| Late payment, a further 5% at 6 months | £250.00 |
| Late payment, a further 5% at 12 months | £250.00 |
| Interest, 365 days at 7.75% | £387.50 |
| Total on top of the £5,000 tax | £1,337.50 |
A further tax-geared penalty of up to £5,000 could also apply at the twelve-month point, which would more than double the cost of the delay. That figure is set by HMRC on the facts and is not included in the total above.
Reducing What You Owe
File the return even if you cannot pay the tax. The two regimes are independent, so filing on time removes the filing penalty entirely even where the payment is late. This is the single cheapest action available and it is regularly missed.
Beyond that, pay whatever you can to shrink the tranches that have not yet fallen due, and contact HMRC about a Time to Pay arrangement rather than waiting. If the delay was caused by your solicitor, they are professionally liable and should cover the penalties and interest. For HMRC's collection powers where the tax stays unpaid, see what happens if you do not pay stamp duty.
Frequently Asked Questions
How much is the penalty for paying stamp duty late?
Two penalties run at once. Filing the return late costs a fixed £100, rising to £200 once the return is more than three months late. Paying the tax late is charged separately at 5% of the unpaid tax at 30 days, a further 5% at six months and a further 5% at twelve months. Interest runs on the unpaid tax on top of both, at the Bank of England base rate plus 4 percentage points, which has been 7.75% since 9 January 2026.
Is there an HMRC stamp duty penalty calculator?
HMRC does not publish a dedicated SDLT penalty calculator. This calculator applies the statutory rules directly: the fixed filing penalties under FA 2003 Sch 10, the 5% late payment tranches under FA 2009 Sch 56, and simple interest at base rate plus 4 percentage points from the day after the 14-day deadline.
How is interest on late stamp duty worked out?
Interest is simple, not compounded. It runs on the unpaid tax from the day after the 14-day deadline until the day the tax is paid, at the Bank of England base rate plus 4 percentage points. On £5,000 of unpaid SDLT left outstanding for a full year at 7.75%, that is £387.50 of interest, before any penalties.
Does the £100 penalty apply if no stamp duty is due?
Yes. A return is required whenever the chargeable consideration exceeds the £40,000 notification threshold, even when the tax works out at £0. Filing that return late still triggers the fixed penalty, though there is nothing for the percentage penalties or interest to bite on.
What is the tax-geared penalty at twelve months?
Once a return is twelve months late, HMRC can charge a further penalty of up to 100% of the tax due. The amount is set by reference to behaviour rather than by formula, so it cannot be predicted precisely. This calculator shows it as a separate exposure ceiling rather than adding an invented figure to the total.
Can a stamp duty penalty be appealed?
Yes. Penalties can be appealed where you have a reasonable excuse for the delay, and the appeal normally has to be made within 30 days of the penalty notice. Interest is different: it is compensation for late payment rather than a penalty, so it is not usually cancelled even where a penalty appeal succeeds.
Do the same penalties apply in Scotland and Wales?
No, and the figures should never be carried across. Revenue Scotland and the Welsh Revenue Authority run their own penalty tiers for LBTT and LTT, both of which have a 30-day filing deadline rather than 14 days, and both charge interest at base rate plus 2.5 percentage points rather than plus 4. This calculator covers England and Northern Ireland only.
Reviewed by
Julie White
ACASDLT Expert since 1999Stamp Duty Land Tax Specialist
ACA and Tax Adviser with a career spanning nearly four decades, specialising in SDLT planning and advisory work since 1999.