New Build Stamp Duty Calculator
Calculate stamp duty on new build properties. Understand SDLT treatment for off-plan purchases, part-exchange deals, and how builder incentives affect your tax liability.
Your Results
Stamp Duty to Pay
£5,000
Effective tax rate: 1.67%
Tax Breakdown
| Band | Rate | Tax |
|---|---|---|
| £0 - £125,000 | 0% | £0 |
| £125,001 - £250,000 | 2% | £2,500 |
| £250,001 - £300,000 | 5% | £2,500 |
| Total | £5,000 | |
£0 - £125,000
0%
£0
£125,001 - £250,000
2%
£2,500
£250,001 - £300,000
5%
£2,500
Total
£5,000
Tax by Band
Added to 25-Year Mortgage
£29/month
Based on 5% interest rate, added to loan amount
Understanding New Build Stamp Duty
How New Builds are Taxed
New build properties are subject to the same stamp duty rates as existing homes. There is no special relief or surcharge specifically for new builds in England. Review our residential property guide for more details.
Off-Plan Considerations
When you buy off-plan, SDLT is due at completion (when you receive the keys), not at exchange. The completion date determines which tax rates apply. Use our guide on how stamp duty is calculated to understand the banded system.
Part-Exchange Schemes
In a part-exchange, you only pay SDLT on the cash price you pay for the new build, not on the value of your old property that the developer takes in exchange.
New Build Stamp Duty Examples
| Property Price | SDLT (Standard) | SDLT (FTB) | SDLT (Additional) | Effective Rate |
|---|---|---|---|---|
| £250,000 | £2,500 | £0 | £15,000 | 1.0% |
| £400,000 | £10,000 | £5,000 | £30,000 | 2.5% |
| £500,000 | £15,000 | £10,000 | £40,000 | 3.0% |
| £750,000 | £27,500 | N/A | £65,000 | 3.7% |
FTB = First-Time Buyer (up to £500k). Additional = Additional dwelling surcharge (5%).
Special Considerations for New Builds
Completion Date is Tax Point
SDLT is calculated based on rates in force at the completion date, not when you exchanged contracts. If rates change between exchange and completion, the new rates apply.
- •Plan for potential rate changes
- •Budget conservatively if long build time
- •Monitor HMRC announcements
Builder Incentives Reduce Price
If the developer pays for carpets, white goods, or contributes to your deposit, these generally reduce the purchase price for SDLT purposes, lowering your tax.
- •Incentives reduce taxable amount
- •Get developer confirmation in writing
- •Include in SDLT return accurately
Ground Rent Implications
For leasehold new builds with ground rent, if the NPV of ground rent exceeds thresholds, it can affect SDLT. Most modern leases have low ground rents, minimizing impact.
- •Check NPV calculation in lease
- •Low ground rents usually have minimal effect
- •Solicitor will calculate if applicable
Warranties Don't Affect SDLT
New build warranties (NHBC, Premier Guarantee, etc.) are separate from the property purchase and do not form part of the consideration for SDLT purposes.
- •Warranty costs not included in SDLT
- •Service charges are separate ongoing costs
- •Only purchase price triggers SDLT
Important: Developer SDLT Contributions
If the developer contributes to your stamp duty bill as an incentive, HMRC may treat this contribution as reducing the purchase price for SDLT purposes. This means the developer effectively pays their contribution twice.
Example: On a £300,000 property, if the developer pays your £5,000 SDLT, HMRC may treat the purchase price as £295,000, requiring SDLT of £4,750. The developer still pays £5,000, but you owe less tax. Always clarify how incentives are structured.
Frequently Asked Questions
Is there a stamp duty exemption for new builds?
No, there is no SDLT exemption specifically for new-build properties. You pay the same stamp duty rates as on any other residential purchase. However, developer incentives such as furniture packages or deposit contributions can reduce the effective purchase price on which SDLT is calculated.
How does part-exchange work for SDLT purposes?
In a part-exchange, the developer buys your existing home and you purchase the new build. SDLT is payable on the full price of the new home, not the net difference. If the new home is an additional property at completion, the 5% surcharge applies but can be reclaimed if your old home sells within 36 months.
Do developer incentives reduce my stamp duty?
Cash incentives, price reductions, and deposit contributions that reduce the actual purchase price will reduce your SDLT. However, non-cash incentives such as furniture packages, white goods, or stamp duty paid by the developer are generally not deducted from the SDLT consideration.
When do I pay SDLT on an off-plan purchase?
SDLT is due within 14 days of legal completion, not when you exchange contracts or reserve the property. For off-plan purchases, this means you do not pay SDLT until the property is built and you complete the purchase, which could be months or years after exchange.
Can first-time buyers get relief on new builds?
Yes. First-time buyer relief applies to new-build properties on the same basis as existing homes. You pay 0% on the first £300,000 and 5% on the portion between £300,001 and £500,000, provided the total price does not exceed £500,000.
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Emma Richardson, MRICS
Chartered Surveyor & Property Tax Specialist
Emma Richardson is a RICS-qualified Chartered Surveyor with over 12 years of experience in UK property taxation. She founded Stamp Duty Calculator to help buyers understand the complex world of property transaction taxes.