This article sets out the rules for each ownership situation, how the higher rates can apply to investors and landlords, what the figures look like in practice, and when SDLT filing obligations arise, even where no tax is owed.
Key Takeaways
Why Does a Lease Extension Trigger Stamp Duty?
This is the question most leaseholders ask first, and it is a fair one. You already own the flat, so it may not feel like you are buying anything new. SDLT comes into the picture because of how a statutory lease extension is treated in law. Under the Leasehold Reform, Housing and Urban Development Act 1993, a qualifying leaseholder's statutory extension results in the surrender of the old lease and the grant of a new lease for 90 years added to the unexpired term, at a peppercorn ground rent. Informal or voluntary extensions follow the same surrender-and-regrant mechanism but the term and rent are agreed between the parties and are not constrained by the 1993 Act.
For SDLT purposes, the grant of that new lease can be a land transaction under the Finance Act 2003. The premium paid to the freeholder may therefore count as chargeable consideration, which is why a lease extension can lead to an SDLT bill. In practice, every residential lease extension in England and Northern Ireland should be checked for SDLT. Even if no tax is payable, an SDLT return may still be required, and while your conveyancer usually deals with the filing, the liability sits with you.
Stamp Duty Thresholds for a Lease Extension in 2025/26
The SDLT position on a lease extension depends mainly on the premium you pay, whether the lease carries more than nominal rent, and whether the higher rates for additional residential properties apply. The rules are different for people who own one residential property and people who own more than one, so it is important to check the right category before working out the SDLT cost.
Single Residential Property Owners
If the flat you are extending is your only residential property anywhere in the world, SDLT on the premium is usually only payable if the premium exceeds £125,000. If the premium is £125,000 or less and only nominal rent is payable, the SDLT charge on the premium is normally zero.
For 2025/26, the standard residential SDLT rates are:
Property or lease premium or transfer value | SDLT rate |
|---|---|
Up to £125,000 | 0% |
£125,001 to £250,000 | 2% |
£250,001 to £925,000 | 5% |
£925,001 to £1.5 million | 10% |
Above £1.5 million | 12% |
In practice, many single property leaseholders do not pay SDLT on a lease extension because the premium is often below the £125,000 threshold. SDLT is more likely to become relevant where the premium is high, for example, on a short lease attached to a valuable flat. If your premium is close to £125,000, it is sensible to have the SDLT cost checked before you agree the final figure with the freeholder.
Multiple property owners and landlords
This may be relevant if, at completion:
- You own two or more residential properties anywhere in the world
- You own the flat jointly with someone who owns another residential property
- Your spouse or civil partner owns another residential property
From 31 October 2024, the higher SDLT rates for residential property start at 5%. For premiums within the lower bands, the rates are:
Property or lease premium or transfer value | SDLT rate |
|---|---|
Up to £125,000 | 5% |
£125,001 to £250,000 | 7% |
£250,001 to £925,000 | 10% |
£925,001 to £1.5 million | 15% |
Above £1.5 million | 17% |
The key point is that a relatively modest lease extension premium can still create an SDLT cost if the higher rates apply. For example, a £45,000 premium charged at 5% would create an SDLT bill of £2,250.
There is an important qualification. Extending the lease on a property you already own does not automatically mean the higher rates apply in every case. The SDLT treatment depends on the legal structure of the lease extension and your wider property position at completion. Your solicitor should confirm the correct treatment before the transaction completes.
Does the Higher SDLT Rate Apply to Lease Extensions?
This is a common trap for landlords. Some assume the higher SDLT rates automatically apply to a buy-to-let lease extension. Others assume they cannot apply because no new property is being bought. Neither view is safe.
Extending a lease does not usually increase the number of properties you own, but the higher rates may still be relevant if the premium is £40,000 or more and you own another residential property at completion. In that case, SDLT may be charged on the premium at the higher rates.
The cost can be high. A £100,000 premium at 5% creates a £5,000 SDLT bill. If you pay when you should not, you may need to claim a refund. If you fail to pay when you should, you risk penalties and interest. Get the SDLT position checked before completion.
Worked Examples
Example 1: Owner occupier with an £80,000 premium
Sarah owns the flat she lives in, and it is her only residential property. She extends her lease for a premium of £80,000.
Because the premium is below the £125,000 nil rate band, there is no SDLT to pay.
- SDLT due: £0
However, because the premium is £40,000 or more, an SDLT return may still need to be filed.
Example 2: Owner occupier with a £175,000 premium
David owns the flat he lives in, and it is his only residential property. He extends the lease for a premium of £175,000.
The first £125,000 is taxed at 0%. The remaining £50,000 is taxed at 2%.
- 0% on £125,000 = £0
- 2% on £50,000 = £1,000
- SDLT due: £1,000
A return must be filed within 14 days of completion.
Example 3: Landlord with a £55,000 premium
James owns his home and a buy-to-let flat. He extends the lease on the buy-to-let for a premium of £55,000.
If the higher rates apply, SDLT is charged on the full premium because it is above £40,000.
- 5% on £55,000 = £2,750
- SDLT due: £2,750
A return must be filed within 14 days of completion.
Example 4: Landlord with a £200,000 premium
Rachel owns three residential properties and extends the lease on one of them for a premium of £200,000.
The higher SDLT rates apply,
- 5% on the first £125,000 = £6,250
- 7% on the next £75,000 = £5,250
- SDLT due: £11,500
A return must be filed within 14 days of completion.
The difference is clear. One leaseholder pays nothing. Another pays £11,500 on the same type of transaction. The deciding factors are the premium, the ownership position and whether the higher rates apply. That is why SDLT should be checked before the premium is agreed, not after completion.
What about Ground Rent, & Does it affect SDLT?
For most lease extensions, ground rent will not affect the SDLT calculation. This is because many statutory and voluntary lease extensions reduce the ground rent to a peppercorn, which means it is effectively zero. Where the new lease has only nominal rent, SDLT is usually calculated on the premium only.
If the new lease includes more than nominal ground rent, the calculation can be more complicated. SDLT may need to be worked out on both the premium and the net present value of the rent over the lease term. Where the new lease overlaps with the old lease, overlap relief may reduce the rent included in the calculation so that the same rent is not counted twice. This is most relevant where the lease includes genuine ground rent, especially escalating or doubling rent. Your conveyancer should check the premium, the rent and any overlap relief before filing the SDLT return.
For example,
Bina pays a £90,000 premium to extend her lease, and the new lease has peppercorn ground rent. SDLT is checked on the premium only. As the premium is below £125,000, there is no SDLT to pay on the premium, although an SDLT return may still be required because the premium is £40,000 or more.
Now compare that with Ben. He pays the same £90,000 premium, but the new lease also includes ground rent with an NPV of £150,000. The premium still creates no SDLT because it is below £125,000. However, the rent NPV is £25,000 above the £125,000 residential NPV threshold, so SDLT on the rent is charged at 1% of £25,000.
- Premium SDLT: £0
- Rent NPV SDLT: £250
- Total SDLT due: £250
This shows why ground rent matters. Peppercorn rent usually keeps the SDLT calculation focused on the premium. Real ground rent can create a second SDLT charge based on the value of the rent over the lease term.
Note
The £125,000 threshold applies separately to the premium and to the NPV of rent. These are two independent SDLT calculations, each with its own nil-rate band. A transaction can produce SDLT on one element and zero on the other, or on both.
What is Overlap Relief on a Lease Extension?
When a lease is extended, the old lease is usually surrendered, and a new one is granted. If the new lease includes ground rent or another regular payment, that rent can count for SDLT and may be included in the net present value calculation alongside any premium.
Overlap relief is only available where the old lease was itself subject to SDLT. This means the old lease must generally have been granted on or after 1 December 2003, the date SDLT replaced stamp duty. Where the old lease was subject to stamp duty rather than SDLT, overlap relief is not available and all rent under the new lease is included in full in the NPV calculation. If the original lease predates December 2003, a specialist should confirm whether any relief applies before the return is filed
For example,
Old lease: 20 years left, with £200 ground rent each year.
New lease: 110 years, with £200 ground rent each year.
The first 20 years of the new lease cover the same period as the old lease. If the relevant rules apply, the rent for those 20 years may not be counted again in full for SDLT.
This means the SDLT rent calculation may be lower, depending on the lease terms and whether the rent has changed.
How Long Do You Have to File an SDLT Return After a Lease Extension?
An SDLT return must usually be filed within 14 days of the effective date of the lease extension. This is normally the completion date, although it can be earlier if the transaction is substantially performed before completion.
The filing requirement should still be checked even where no SDLT is payable. For a lease extension granted for a term of seven years or more, a return is required where the premium exceeds £40,000 or the annual rent exceeds £1,000 — regardless of whether any SDLT is actually payable (FA 2003 s.77A). This threshold applies to all leaseholders, not only those subject to the higher rates. A single-property owner-occupier paying an £80,000 premium on a statutory extension must therefore file a return even though no SDLT is due.
If the return is late, HMRC can charge penalties and interest. In most cases, the solicitor or licensed conveyancer will file the return, but the leaseholder should take advice if the filing position is unclear.
Scotland and Wales
If the property is in Scotland, Land and Buildings Transaction Tax (LBTT) applies under the rules administered by Revenue Scotland, not SDLT. If the property is in Wales, Land Transaction Tax (LTT) applies under the rules set by the Welsh Revenue Authority. Both regimes have separate rates, thresholds, and return requirements.
Informal lease extensions: Do the same rules apply?
Not all lease extensions are done through the formal legal lease extensions process. Sometimes, the leaseholder and freeholder simply agree a deal between themselves. This is usually called an informal or voluntary lease extension.
For SDLT, what matters is not what the deal is called, but what it does legally. If the old lease is replaced with a new, longer lease, SDLT may need to be checked. If you pay a premium for that new lease, the premium may count for SDLT. In simple terms, an informal lease extension does not automatically avoid stamp duty, so your solicitor should check the position before completion.
Frequently Asked Questions
Possibly. An informal or voluntary lease extension does not avoid SDLT just because it is agreed directly with the landlord. If the deal replaces the old lease with a new, longer lease, or is treated as a surrender and regrant, any premium paid may need to be checked for SDLT. The route may be informal, but the SDLT question still needs to be asked.
Yes, it can. Commercial and mixed-use leases have different SDLT rules from residential leases. For non-residential lease premiums, the nil-rate threshold is £150,000. If the lease includes rent, SDLT may also be calculated on the net present value of that rent using the non-residential rates. Commercial lease extensions should be checked separately because both the premium and rent can affect the final SDLT bill.
Usually, no. SDLT is charged on chargeable consideration, such as the premium paid for the lease. Your own solicitor, surveyor and valuation fees are generally paid for separate professional services, so they are not normally part of the SDLT calculation.
You’ll pay a fixed penalty of £100 if the return is up to 3 months late, and £200 if it is more than 3 months late. If the return is not filed within 12 months, a tax-based penalty can also apply, which may be up to the full amount of the tax due. Interest may also be charged in more serious or prolonged cases.
Yes, HMRC’s SDLT lease calculator can be a useful starting point, especially where rent or net present value is involved. However, lease extensions can need extra checks, particularly where there is ground rent, a high premium, commercial property, mixed-use property or possible higher rates. If the facts are not straightforward, ask your solicitor to confirm the SDLT position before completion.
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