Property Flip Calculator: How to Calculate Your Profit on a UK Flip

2026-04-03

Flipping property in the UK can be highly profitable, but only if you know your numbers before you buy. The difference between a successful flip and a money pit usually comes down to costs that weren't accounted for upfront: stamp duty surcharges, unexpected renovation overruns, bridging finance that runs longer than planned, and a Capital Gains Tax bill that wipes out half your paper profit.

This guide breaks down every cost in a UK property flip, walks through a realistic worked example, and points you to the tools that do the maths for you.

What Does "Flipping" Actually Mean?

In the UK property context, flipping means buying a property, improving it (or sometimes just benefiting from market timing), and selling it for a profit within a relatively short period, typically 3 to 12 months. It's distinct from buy-to-let investing because the goal is capital gain, not rental income.

The basic formula looks simple:

Profit = Sale Price - Purchase Price - All Costs

The catch is in "all costs." Most first-time flippers dramatically underestimate them.

The True Cost Stack of a UK Property Flip

Here's every cost you need to factor in, roughly in the order they hit your bank account:

1. Purchase Costs

• Property price — your agreed purchase price
• Stamp Duty (SDLT) — if this isn't your only property, you're paying the 5% additional property surcharge on top of standard rates. On a £200,000 purchase, that's £8,500 in SDLT alone
• Legal fees — typically £1,000 to £2,000 for conveyancing
• Survey — £400 to £1,500 depending on type

[!warning] The 5% surcharge catches most flippers If you own your own home, any additional property purchase attracts the 5% SDLT surcharge (increased from 3% in October 2024). On a £250,000 flip property, that's £11,250 in stamp duty. This is often the single largest cost after the renovation itself.

:::tool sdlt-calculator Calculate Your Exact Stamp Duty :::

2. Finance Costs

Most flippers use short-term bridging finance rather than a standard mortgage. Bridging loans are designed for exactly this purpose, but they're not cheap:

• Monthly interest — typically 0.65% to 0.85% per month (7.8% to 10.2% annualised)
• Arrangement fee — usually 1-2% of the loan
• Valuation fee — £300 to £500
• Exit fee — often 1% of the loan or a flat fee
• Legal fees — the lender's solicitor costs, on top of your own

On a £150,000 bridging loan held for 6 months at 0.75% monthly with a 2% arrangement fee, your total finance cost is around £9,750. That's money that comes straight off your profit.

:::tool bridging-calculator Calculate Your Bridging Costs :::

3. Renovation Costs

This is where flips succeed or fail. The renovation needs to add more value than it costs, and the budget needs to be realistic.

Common flip renovations and typical costs:

• Full redecoration — £3,000 to £8,000
• New kitchen — £5,000 to £15,000
• New bathroom — £3,000 to £8,000
• Rewiring — £3,000 to £5,000
• New central heating — £3,000 to £6,000
• Structural work — £5,000 to £20,000+

[!tip] Build in a contingency Budget 15-20% above your renovation estimate. Old properties always have surprises behind the walls, and material prices have been volatile since the energy shock. A contingency isn't pessimism, it's experience.

The Renovation Spec tool lets you build a room-by-room budget with UK-specific pricing before you make an offer.

4. Selling Costs

• Estate agent fees — 1% to 1.5% plus VAT (so 1.2% to 1.8% effective)
• Legal fees — another £1,000 to £1,500
• EPC certificate — £60 to £120

5. Capital Gains Tax

This is the cost most flippers discover too late. If you sell a property that isn't your primary residence, you owe Capital Gains Tax on the profit.

:::stats 18% | CGT Basic Rate 24% | CGT Higher Rate £3,000 | CGT Allowance (2025/26) :::

The rate depends on your income. If your salary plus the property gain keeps you in basic rate, you pay 18%. If it pushes you into higher rate, the portion above the threshold is taxed at 24%.

[!note] HMRC can reclassify frequent flips as trading If you flip multiple properties regularly, HMRC may treat you as a property trader rather than an investor. Trading profits are taxed as income (up to 45%) rather than capital gains. If you're doing more than 2-3 flips per year, get specialist tax advice.

Use the Property Gains Tax calculator to estimate your exact liability before committing to a flip.

Worked Example: A Realistic UK Flip

Let's walk through a real-world scenario to see how the numbers work.

The deal: A 3-bed terrace in a Northern city, bought at auction for £150,000. Needs a full renovation. Comparable renovated properties are selling for £215,000. The flipper has a £55,000 salary and owns their own home.

:::stats £215,000 | Sale Price £204,770 | Total Costs £10,230 | Gross Profit £1,735 | CGT (24%, after £3k) £8,495 | Net Profit :::

That's £8,495 net profit on a project that took 6 months and required approximately £50,000 cash upfront (deposit plus renovation costs before drawdown). Not terrible, but not life-changing either. And that's assuming everything goes to plan — no overruns, no chain collapses, no hidden damp.

[!tip] The margin test Before committing to a flip, check whether your expected profit survives a 10% price reduction and a 20% cost overrun. If it doesn't, the risk-reward ratio is wrong. Walk away.

When Flipping Works

Flipping works best when:

• You buy significantly below market value (auction, repossession, probate)
• The renovation is cosmetic, not structural (decoration, kitchen, bathroom)
• You can complete quickly (under 6 months) to minimise finance costs
• The exit market is strong (high demand, low stock in the area)
• You have cash or cheap access to finance

When Flipping Doesn't Work

Flipping is risky when:

• You're buying at market value hoping to add value through renovation
• The renovation involves significant structural or planning work
• You're relying on house price growth to make the maths work
• Bridging rates are high and you don't have a clear exit timeline
• You haven't accounted for all costs (especially SDLT surcharge and CGT)

The most common mistake is underestimating total costs and overestimating the post-renovation sale price. Run the numbers honestly. If the deal only works with optimistic assumptions, it's not a deal.

:::video deal-analyser :::

:::tool deal-analyser Stress Test Your Deal :::

Run Your Own Numbers

Every flip is different. Use the SDLT Calculator for stamp duty, the Bridging Calculator for finance costs, the Renovation Spec for your refurb budget, and the Property Gains Tax calculator for your CGT liability. Or start with the Deal Analyser to see the full picture in one place.

:::tool deal-analyser Analyse Your Flip :::

Calculations in this guide are for illustrative purposes only and should not be treated as financial advice. Property flipping carries significant financial risk. Always seek professional advice before committing to a purchase.