How to Analyse a Property Deal in the UK: The Complete Framework

2026-05-16

Why Most Property Investors Skip the Analysis — and Regret It

There's a pattern in every property investment community: someone buys a "great deal" based on the asking price and the Rightmove rental estimate, skips the detailed analysis, and six months later discovers they're cash-flow negative after mortgage payments, management fees, insurance, voids, and the stamp duty they forgot to factor in.

Property deal analysis isn't complicated. It's arithmetic. But you have to include every number, not just the ones that make the deal look good. This guide walks through the complete framework for analysing any UK property deal — whether you're buying a single buy-to-let, running a BRRR strategy, or flipping for profit.

Step 1: Calculate Your Total Acquisition Cost

The purchase price is not what the property costs you. The total acquisition cost includes everything you pay to get the keys:

• Purchase price — the agreed price
• Stamp duty (SDLT) — including the 5% additional property surcharge if you already own a property. On a £200,000 BTL, that's £10,000 in SDLT alone
• Legal fees — typically £1,000 to £2,000 for conveyancing
• Survey costs — £400 to £1,500 depending on the type
• Mortgage arrangement fee — usually £999 to £1,999, sometimes added to the loan
• Broker fee — if using a mortgage broker, typically £500 to £1,000

On a £200,000 buy-to-let purchase, your total acquisition cost is typically £215,000 to £218,000. That's the real number your returns should be measured against, not the headline price.

Step 2: Calculate Your Cash Invested

Cash invested is the money that comes out of your bank account — it's the number that determines your ROI.

Cash invested = Deposit + Stamp duty + Legal fees + Survey + Arrangement fee + Broker fee + Any renovation costs

On a £200,000 property with a 75% LTV mortgage:

• Deposit (25%): £50,000
• Stamp duty: £10,000
• Legal + survey + fees: £4,000
• Total cash invested: £64,000

This is the denominator in your ROI calculation. Getting it wrong — typically by forgetting stamp duty or fees — inflates your projected return by 15-25%.

Step 3: Calculate Your Gross Rental Income

Gross rental income is the total rent you'd receive if the property were let every day of the year with no voids. Use comparable evidence, not hope:

• Check Rightmove and OpenRent for similar properties currently listed in the same postcode
• Check the ONS Private Rental Index for the local authority area
• Ask a local letting agent for a rental appraisal — they'll give you a range
• Use the lower end of the range for your analysis, not the upper

If three comparable 2-bed flats in the area are listed at £850, £900, and £875, use £850 as your base case. If the property needs work before it's lettable, use the post-renovation rental value but make sure the renovation cost is in your cash invested figure.

Step 4: Calculate Gross Yield

Gross yield is the simplest measure of return and the one most often quoted — but also the most misleading if used in isolation.

Gross yield = (Annual rent ÷ Purchase price) × 100

On a £200,000 property renting at £850/month: (£10,200 ÷ £200,000) × 100 = 5.1%

Gross yield is useful for comparing properties quickly, but it ignores every cost between collecting rent and keeping the profit. A property yielding 7% gross can easily yield 2% net after costs — or even go negative.

Step 5: Map Every Monthly Cost

This is where most analyses fall short. Every recurring monthly cost needs to be listed and totalled:

• Mortgage payment — the largest single cost. On a £150,000 interest-only mortgage at 5%, that's £625/month
• Management fee — if using an agent, typically 8-12% of rent. On £850/month, that's £68-£102
• Insurance — landlord buildings + contents, typically £20-£40/month
• Ground rent + service charge — leasehold properties only, can be £50-£300/month
• Maintenance allowance — budget 8-10% of rent for ongoing repairs. On £850/month, that's £68-£85
• Accountancy — if you use an accountant for your tax return, £15-£30/month amortised
• Void allowance — budget 4-8% of annual rent for empty periods

Total monthly costs on a typical £200,000 BTL at 75% LTV: £850 to £1,050/month. If the rent is £850, you can see immediately whether the deal is cash-flow positive or negative.

Step 6: Calculate Net Yield and Monthly Cash Flow

Monthly cash flow = Gross monthly rent - Total monthly costs

Annual cash flow = (Monthly cash flow × 12) - Annual void cost

Net yield = Annual cash flow ÷ Purchase price × 100

Using our example: £850 rent - £950 costs = -£100/month. That's a negative cash flow of £1,200/year. The net yield is -0.6%. This deal doesn't work at this purchase price and interest rate.

Adjust the purchase price downward until the cash flow turns positive, or increase the rent assumption if the property has value-add potential. The analysis tells you exactly what price makes the deal work.

Step 7: Calculate ROI

ROI measures your return on the cash you actually invested, not the property value.

ROI = Annual cash flow ÷ Cash invested × 100

If the annual cash flow is £2,400 and you invested £64,000: ROI = 3.75%. That means your £64,000 is earning 3.75% per year in cash returns, before any capital appreciation.

A deal with 3.75% cash ROI might still be attractive if the area has strong capital growth prospects — you're effectively being paid 3.75% to wait for the property to appreciate. A deal with negative ROI needs either a lower price, higher rent, or a different strategy.

Step 8: Stress Test the Deal

The numbers above assume everything goes to plan. Stress testing shows you what happens when it doesn't:

• Interest rate +2%: If your fix expires and rates are higher, does the deal still cash-flow?
• Void period doubles: If you have two months void instead of one, are you still positive?
• Rent drops 10%: If the market softens, does the deal survive?
• Major repair: If you need a new boiler (£3,000) in year one, does the annual return justify the risk?

A good deal survives stress testing. A marginal deal doesn't. If a 2% rate rise turns your cash flow negative, the deal is riskier than the headline yield suggests.

The 60-Second Screening Test

Before running a full analysis, screen properties with this quick test:

• Gross yield below 5%: Unlikely to cash-flow after costs unless you're buying cash (no mortgage)
• Gross yield 5-7%: Might work — run the full analysis
• Gross yield above 7%: Likely cash-flow positive — but verify the rental evidence is solid and check why the yield is high (sometimes it's because the property has problems)

This isn't a rule — it's a filter. Properties below 5% gross yield in the current interest rate environment rarely cash-flow positively with a 75% LTV mortgage. Don't waste time analysing deals that fail the screening test.

Run the Numbers Every Time

Every property deal deserves a full analysis. Not a back-of-envelope guess, not a "it feels like a good area" assumption, and definitely not a trust-the-agent approach. Run the eight steps above, stress test the result, and let the maths decide.

The difference between a good deal and a bad deal is never visible in the listing photos. It's in the spreadsheet. Or better yet, in a purpose-built tool that does the maths for you and stress-tests the scenarios you'd forget to check manually.