Net Present Value (NPV): Lease SDLT Calculation
Net Present Value (NPV) is the method used to calculate stamp duty on lease transactions. It represents the total rent over the lease term discounted to today's value using HMRC's 3.5% rate.
Last verified: April 2026 | Source: GOV.UK
Key Takeaways
- •NPV is used to calculate SDLT on the rent element of lease transactions.
- •HMRC's discount rate is 3.5% per year — reflecting the time value of money.
- •For new residential leases, SDLT applies at 1% on the portion of NPV above £125,000.
- •NPV only applies to new leases — not to buying (assigning) an existing lease.
- •Any premium (upfront payment) for a lease is assessed separately under standard SDLT rates.
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What Is NPV
When you take out a new lease, SDLT is potentially due on two separate elements: any premium paid upfront (calculated at standard SDLT rates) and the rent to be paid over the lease term (calculated using Net Present Value).
NPV represents the total value of all future rent payments in today's money. Because money received in the future is worth less than money today (due to inflation and the opportunity cost of capital), each future payment is discounted back to its present-day equivalent using HMRC's prescribed rate of 3.5% per year.
How NPV Is Calculated
For each year of the lease, the rent for that year is divided by (1 + 0.035) raised to the power of that year number. These discounted figures are then added together to arrive at the NPV.
Simplified formula
NPV = Rent Year 1 / 1.035 + Rent Year 2 / 1.035² + ... + Rent Year N / 1.035^N
In practice, rent is often level across the lease term. HMRC publishes tables of "net present value factors" and provides a lease duty calculator on GOV.UK so buyers and solicitors can calculate the NPV without doing the arithmetic manually.
HMRC's 3.5% discount rate is set by the Treasury. It reflects the long-term return the government assumes on public sector investments and has not changed since SDLT was introduced in 2003.
Residential Leases
For new residential leases, SDLT on the NPV of the rent applies at:
| NPV of rent | SDLT rate |
|---|---|
| Up to £125,000 | 0% |
| Above £125,000 | 1% |
Note that this SDLT on the rent is in addition to any SDLT due on a lease premium. The two elements are calculated and paid separately.
Non-Residential Leases
For new non-residential (commercial) leases, SDLT on the NPV of the rent applies at:
| NPV of rent | SDLT rate |
|---|---|
| Up to £150,000 | 0% |
| £150,001 to £5 million | 1% |
| Above £5 million | 2% |
Assigned vs New Leases
NPV only applies to new leases. When you buy an existing leasehold from another owner (an assignment), you are purchasing a property interest — not entering into a new lease. SDLT on an assigned leasehold is calculated on the premium paid (the price you pay to the outgoing leaseholder), at standard SDLT rates.
There is no NPV calculation on the remaining lease rent in an assignment — NPV is only relevant at the point when the original lease was granted.
HMRC's Lease Duty Calculator
HMRC provides a dedicated Stamp Duty Land Tax lease transaction calculator on GOV.UK. It calculates the NPV automatically when you enter the annual rent, lease term, and any premium paid. Solicitors and conveyancers typically use this tool when completing the SDLT return for a new lease.
Worked Example
New residential lease: £15,000 per year for 25 years, no premium
- Annual rent: £15,000
- Term: 25 years
- HMRC discount rate: 3.5%
- Approximate NPV: £258,000 (using HMRC tables)
- NPV above £125,000 threshold: £133,000
- SDLT on rent (1% of £133,000): £1,330
- SDLT on premium: £0 (no premium)
- Total SDLT: £1,330
Official Government Source
For official guidance on SDLT on leasehold purchases:
Stamp Duty Land Tax: leasehold purchases — GOV.UKFrequently Asked Questions
What is Net Present Value in stamp duty?
In stamp duty, Net Present Value (NPV) is the method used to calculate tax on lease transactions. It represents all future rent payments discounted back to their present-day value using a 3.5% discount rate. SDLT is then charged on the NPV of the rent in addition to any lease premium.
When does NPV trigger SDLT on a residential lease?
For new residential leases, if the NPV of the total rent over the lease term exceeds £125,000 (the residential SDLT threshold), you pay 1% SDLT on the portion of NPV above £125,000. This only applies to new leases, not assigned (existing) leases.
How is NPV calculated?
NPV is calculated by adding together each year's rent, discounted by the HMRC-specified rate of 3.5% per year. In simple terms: if rent is £10,000 per year for 50 years, NPV is less than the total £500,000 because future payments are worth less in today's money. HMRC provides a lease duty calculator to do this automatically.
In this article
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 Calculate My Stamp Duty UK to help buyers understand the complex world of property transaction taxes.