Flip deal appraisal calculator
Before you offer, check the deal stacks up. Enter the numbers below for an instant profit, margin and ROI on a buy-refurb-sell, then build the full costed schedule of works and appraisal.
How to appraise a flip
- 1Start from the GDV
Work back from a realistic resale value (GDV) based on sold comparables — not asking prices. Everything is judged against this number.
- 2Add every cost
Purchase, stamp duty (additional-property rates for most investors), refurb works, finance (bridging interest + fees), holding costs and selling fees. Missing costs is how flips lose money.
- 3Target a sensible margin
Many flippers want roughly 20%+ profit on cost, or a £25k–£40k+ net profit, to absorb market movement and overruns. Thin margins leave no room for surprises.
- 4Spec to the resale market
Choose a kitchen, bathroom and finish that appeal to your buyer — over-spec wastes margin, under-spec costs you on the sale.
The quick calculator above uses an estimated bridging cost and additional-property stamp duty to give you a fast read on the deal. The full ScopeWise appraisal goes further: it ties the works figure to an itemised schedule, models the bridge interest over your actual term, and prints the assumptions on a lender-ready PDF — so the same numbers that tell you the deal works also raise the finance to do it.
The number that sinks flips is the GDV, because it's the biggest and the least in your control — so stress-test it. Our 70% rule guide covers a fast first filter, and the stamp duty guide the buying cost that most often turns a good-looking deal bad. Cost the works with the refurbishment calculator, then commit the whole deal to a schedule of works.
Costs a flip appraisal must include
| Cost | Typical basis |
|---|---|
| Stamp Duty Land Tax | Additional-property rates (5% surcharge) |
| Refurbishment works | Itemised schedule + 10–15% contingency |
| Bridging finance | Interest (rate × term) + arrangement & exit fees |
| Holding costs | Council tax, utilities, insurance × months held |
| Selling fees | Estate agent + conveyancing (~1.5–2.5%) |
| Legals on purchase | Conveyancing, searches |
ScopeWise auto-estimates SDLT and bridging costs in the full appraisal.
Frequently asked questions
What profit margin should a flip make?+
A common rule of thumb is at least 20% profit on cost, or a net profit of £25,000–£40,000+ on a typical residential flip, to give a buffer against cost overruns and a softening market. Tighter margins carry real risk if anything slips.
Do I pay the stamp duty surcharge on a flip?+
Most investors and companies buying an additional dwelling pay the 5% SDLT surcharge on top of standard residential rates (England & NI). It's a significant cost — the calculator and full appraisal estimate it for you.
How is profit on cost different from ROI?+
Profit on cost is net profit ÷ total project cost. ROI (return on cash) is net profit ÷ the cash you actually put in (equity), which is higher when you use leverage. Lenders and investors look at both.
What is the 70% rule for flipping houses?+
The 70% rule says don't pay more than 70% of the after-repair value (GDV) minus the refurb cost — the 30% buffer is meant to cover buying, finance and selling costs plus your profit. It's a useful first filter, but it bundles too much into one number; appraise the survivors properly. See our full 70% rule guide.
How much money do I need to flip a house?+
Beyond the deposit (bridging typically funds up to ~70–75% of purchase), you need cash for the stamp duty surcharge, refurbishment (often funded in arrears via drawdowns, so you fund the first phase), finance fees, holding and selling costs — plus a contingency. Model it all in the appraisal so you know the real cash requirement, not just the deposit.
Is flipping houses profitable in the UK?+
It can be, but the margin is easily eaten by the stamp duty surcharge, bridging interest, an overrunning refurb and a soft sale. The profitable flippers buy well, cost the works accurately, and stress-test the GDV and timeline before offering — which is exactly what a proper appraisal forces you to do.
Related tools & guides
Want to know how these figures are calculated? See our cost methodology.
Cost figures shown are indicative estimates, not quotations. You are responsible for verifying all costs (obtain contractor quotes) and any figures submitted to a lender. ScopeWise is a documentation tool, not financial, tax, structural or planning advice. HMO compliance prompts are guidance only — confirm requirements with your local council, as standards and licensing vary by authority.