Transferring a personally-held UK buy-to-let portfolio into a limited company triggers three one-off costs: SDLT on the deemed market-value sale (per property at additional-property rates with the +5% surcharge), CGT on the deemed disposal of each property, and refinancing costs as personal mortgages are redeemed and replaced with SPV products. This calculator models the all-in cost correctly — including the per-property SDLT calculation that most simple tools get wrong — and surfaces the break-even year against your annual Section 24 saving.
Portfolio Incorporation Cost
Incorporating an existing portfolio triggers SDLT (deemed market-value transfer), CGT (deemed disposal), and refi/admin overhead. Here's the number that decides whether incorporation pays back — and when.
Section 162 incorporation relief — tightened from 6 April 2026
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One-off cost to incorporate
SDLT on transfer
£53,000
CGT on transfer
£71,280
Total one-off
£138,280
Break-even
14 yrs
Net annual saving: £10,200
Advanced reliefs we flag but don't auto-apply: incorporation relief (s162 TCGA), SDLT partnership-incorporation relief, multiple dwellings relief. Consult a specialist before acting.
Cost breakdown
Where the one-off bill comes from. SDLT is usually the biggest line.
Note: SDLT calculated per-property at additional-property rates (the engine fix from May 2026). Single-transaction treatment would have shown £80,000 — an overstatement of £27,000.
Cumulative S24 saving vs one-off cost
The year the savings cross the flat cost line is your break-even.
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Related guides
Plain-English explainers for the rules behind this calculator.
Frequently asked questions
Answers to the questions UK property investors most often have about this tool and the underlying rules.
- Why is SDLT calculated per property and not on the whole portfolio?
- Each property in an incorporation is a separate transaction in HMRC's eyes — SDLT bands apply per property, not summed across the portfolio. Tools that sum the portfolio value and apply bands once dramatically overstate SDLT. For five £200k properties (£1m total), the correct figure is 5 × £11,500 = £57,500, not the £93,750 you'd get treating it as a single £1m transaction.
- What is Section 162 incorporation relief?
- TCGA 1992 s162 defers the CGT on transferring a business into a company in exchange for shares — your gain rolls into the share base cost instead of crystallising immediately. To qualify, the rental activity must constitute a "business" under the Ramsay v HMRC test: active management of multiple properties at ~20+ hours per week. HMRC has tightened scrutiny on landlord s162 claims from April 2026 — statutory clearance is no longer available.
- What is SDLT partnership-incorporation relief?
- If the BTL portfolio has been operated as a genuine partnership for at least 2 years prior to incorporation (with a partnership tax return filed), Finance Act 2003 Sch 15 para 18 can eliminate SDLT on transfer entirely. Setting up a partnership purely for the 2-year clock is generally treated as artificial — the partnership must have a genuine business purpose.
- How long until incorporation pays back?
- It depends on the one-off cost (mostly CGT + SDLT) versus the annual Section 24 saving once incorporated (typically £3-15k per £100k of mortgage interest, depending on tax band). For a higher-rate landlord with a £1m portfolio and £40k of annual mortgage interest, payback is usually 8-15 years. The calculator gives you the specific break-even.