Selling can be the right move. The mistake is deciding based on the headline sale price rather than the true cash you will bank after mortgage redemption costs and Capital Gains Tax. This practical calculator shows you how to work out your net sale proceeds and compare them to a refinance or partial sell-down that might deliver better cash flow, less hassle, or a smoother path into retirement.
Companion guides
These pieces sit alongside this calculator and help you compare selling with refinancing or rebalancing:
Case Study: How David Retired From Being a Landlord and Passed On His Legacy Early
How Landlords Can Future-Proof Their Property Portfolios and Inspire the Next Generation
What “net proceeds” actually means
Net sale proceeds = Sale price − selling costs (agent, legal, compliance, void/works) − mortgage redemption (balance + any ERC) − Capital Gains Tax (after reliefs and allowances). That final number is what you can actually redeploy to reduce debt elsewhere, reinvest, or support retirement spending.
Gather these inputs first
- AVM value (for a quick starting point) or a current market appraisal
- Mortgage balance and early repayment charge (ERC), if any
- Agent fee (%) and legal fee (£), plus any compliance costs (EPC upgrade, EICR, gas cert, minor works)
- Base cost (purchase price) and documented improvements (capital, not routine repairs)
- Ownership split (if joint owners) and your likely income tax band(s) for the disposal year
- Annual exemption position and any brought-forward capital losses
The step-by-step calculator (single property)
- Start with price: AVM or agreed sale price.
- Subtract selling costs: agent fee + legal + compliance + expected void/works = Total selling costs.
- Redeem mortgage: current balance + ERC = Total redemption.
- Cash before tax: price − selling costs − redemption.
- Compute the gain: price − (base cost + capital improvements + directly attributable selling costs).
- Apply allowances: deduct your available annual exemption and any allowable losses.
- Apply residential property CGT rates: calculate CGT at basic-rate and higher-rate bands as they apply to you.
- Net proceeds: cash before tax − CGT payable.
Note: For UK residential property disposals, the date of disposal is the date of exchange (not completion). Plan timing around tax year-end accordingly and ask your accountant to confirm current reporting deadlines for CGT on UK property disposals.
Worked example A — single owner, higher-rate taxpayer
Assumptions (illustrative only)
- Sale price £300,000; agent 1.5% (£4,500); legal £1,500
- Mortgage balance £180,000; ERC 2% (£3,600)
- Base cost £200,000; documented improvements £10,000
- Annual exemption already used elsewhere; no brought-forward losses
Cash before tax:
Price £300,000 − selling costs (£4,500 + £1,500) £6,000 − redemption (£180,000 + £3,600) £183,600 = £110,400
Capital gain:
£300,000 − (£200,000 + £10,000) − £6,000 = £84,000
CGT (illustrative at higher-rate for residential property): £84,000 × 24% = £20,160
Net proceeds after CGT: £110,400 − £20,160 = £90,240
Interpretation: a £300k sale leaves roughly £90k in hand after costs, redemption and tax.
Worked example B — joint owners in different tax bands
Assumptions (as above) and equal ownership (50:50). Owner 1 is basic-rate; Owner 2 is higher-rate. Each has the annual exemption available.
Split the gain: £84,000 ÷ 2 = £42,000 each.
Less annual exemption (illustrative): £42,000 − £3,000 = £39,000 taxable gain each.
CGT: Owner 1 (basic-rate band available): £39,000 × 18% = £7,020. Owner 2 (higher-rate): £39,000 × 24% = £9,360.
Total CGT: £16,380.
Net proceeds after CGT: same cash before tax £110,400 − £16,380 = £94,020.
Interpretation: ownership splits and available bands matter. Staging disposals and using two tax years can improve outcomes.
Portfolio view — scaling across multiple properties
- Run the calculator per property, then sum the net proceeds column.
- Check if selling two weaker units to retire expensive debt on the keepers lifts free cash flow more than selling a single strong unit.
- Model a refinance-and-de-gear plan to a target portfolio LTV of about 40 per cent with a one-year liquidity buffer.
Ways to improve the number (before you list)
- Sequence across tax years: exchange some contracts before and some after 5 April to use allowances twice (subject to market practicalities).
- Use losses: set brought-forward losses against gains where appropriate.
- Evidence capital improvements: keep invoices for qualifying works; they increase base cost and reduce the gain.
- ERC timing: check if waiting for the ERC step-down materially improves net proceeds.
- Fee discipline: small reductions in agent fee or legals can add up across a portfolio.
When selling is sensible
- Persistent negative or marginal cash flow with limited scope for a rent reset
- Large capex looming with weak payback
- Concentration risk in a sub-market you no longer back
- Retirement simplicity is the priority
When refinancing or partial sell-down is better
- You can reach a resilient target LTV and materially lift free cash flow by retiring expensive debt
- Selective disposals stabilise the whole without losing your best assets
- The unit you planned to sell is one of your top performers and would be costly to replace
Numbers to prepare before you speak to buyers or lenders
- AVM snapshot for each property and a portfolio total
- Debt schedule with balances, rates, maturities and ERCs
- Estimated selling costs and a simple CGT calculation (with ownership splits)
- Three-line cash flow for each unit: rent, operating costs, interest
- One-page plan: sell, refinance, or rebalance, with reasons
How we help
Our consultation service covers de-leveraging, retirement planning, business continuity and legacy planning for landlords. The process is written, structured and client-led. It is not a phone call. We base our recommendations on a conditional-logic Fact Find followed by focused email exchanges. Your inputs drive the analysis and the priorities. Our role is to organise the options, test commercial feasibility, and document an implementation plan that your own accountant, solicitor and regulated adviser can execute.
Scope of topics we cover
- Business continuity and lender management, including target LTV setting and liquidity buffers
- Succession and legacy planning that keeps control tidy, including equalising between children without selling core assets
- Structuring options such as LLP governance, company housekeeping and Family Investment Company considerations, with clear signposting to legal drafting where needed
- Life insurance trust and loan-back mechanics, including trustee duties, loan terms and security options
- Refinancing pathways, broker briefing notes, and the documents underwriters expect to see
- Valuations approach using AVMs for portfolio snapshots and when to commission a full valuation
- Director loan accounts and intra-group balances, with tidy-up options before, during and after an owner’s death
- Insurance strategy at a commercial level, including whole of life sizing logic and ownership routes, with referral to a regulated adviser for product selection
- Governance pack items such as shareholders’ agreements, members’ agreements, Wills and LPAs, flagged for your solicitor to draft or update
How it works
- You complete our conditional-logic Fact Find and property schedule
- We follow up by email to clarify objectives and any missing data
- We prepare a tailored 30+ page written report setting out your options, worked examples, risks, and recommended next steps
What you receive
- A 30+ page personalised report with numbered recommendations and a clear sequence of actions
⚖️ Important Notice – Scope of Planning Support
This article is for information only. Calculations are illustrative and based on your inputs. Please ask your accountant to verify CGT and your solicitor to confirm legal steps before you proceed with a sale or refinance.
Property118 does not provide formally regulated or insured advice on law, tax, or financial services, including life insurance, mortgages, pensions, or investment products.
Our role is to present researched planning recommendations based on our interpretation of current legislation, HMRC guidance, established case law, and our extensive experience supporting UK landlords.
While our bespoke recommendations are always based on detailed research, we strongly recommend that you share them with appropriately regulated professional advisers, such as your solicitor, accountant, or financial adviser, and ask them to review and confirm the correct legal and tax treatment before proceeding.
Specific regulated responsibilities include:
- Tax calculations and filings – Your accountant
- Stamp Duty Land Tax and equivalents – Your solicitor
- Company structuring – Your accountant
- Legal drafting – Your solicitor or Barrister
- Trust, wills, and succession planning – A STEP-qualified solicitor or trust specialist
- Life cover, pensions, and other financial services – An FCA-regulated financial adviser
Property118 is happy to work with your existing advisers or introduce you to trusted professionals. Our planning is designed to support you in making commercially led decisions that can then be implemented through appropriate regulated channels.
