The SDLT return deadline is 14 days after the effective date of the transaction — usually completion. The tax must be paid by the same date. The deadline applies even if no tax is due, where a return is required.
When is the SDLT return due?
The deadline was cut from 30 days to 14 days for transactions with an effective date on or after 1 March 2019. If the 14th day falls at a weekend or on a bank holiday, the return still has to reach HMRC by then — there is no extension, so file early.
The effective date
The effective date is normally completion. It can be earlier if the contract is substantially performed first — for example, if the buyer moves in, or pays 90% or more of the price, before completion.
What are the penalties for filing late?
| When the return is filed | Penalty |
|---|---|
| Up to 3 months late | £100 |
| More than 3 months late | £200 |
| More than 12 months late | Up to the full amount of tax due, as well |
The fixed penalties apply automatically, even when no tax is due on the return.
Interest on late payment
Interest runs on any tax paid late, from the day after the deadline until it is paid. HMRC can also charge penalties for inaccurate returns.
Can you appeal a late-filing penalty?
You can appeal if you had a reasonable excuse — an unexpected event outside your control that stopped you filing, such as serious illness or a failure of HMRC's online service. Appeals are normally made within 30 days of the penalty notice.
Amending a return
Mistakes can usually be corrected by amending the return within 12 months of the filing date. After that, an overpayment relief claim may be possible within 4 years.
FileSDLTonline tracks the 14-day deadline on every case and flags returns that are due within three days.