CURRENT POSITION
Strong affordability
Plenty of monthly room — you could absorb meaningful rate rises or life changes without strain.
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UK property flip ROI calculator — net profit, ROI on cash, profit margin, annualised return, and break-even resale price.
MORTGAGE PAYMENT
Repayment mortgage at 5% over 30 years.
LOAN TO VALUE
90%
You are between 85% and 90% LTV. This can still be workable, but increasing the deposit may improve product choice.
TOTAL REPAYABLE
£434,826
Over the full 30-year term, including £209,826 of interest.
Monthly bills
£450
Council tax, utilities, service charge, and maintenance.
Total monthly cost
£1,658
Mortgage payment + monthly bills.
Monthly surplus
£2,429
More than 50% of income is left after housing costs. That usually suggests a healthier monthly buffer.
YOUR NUMBERS
Mortgage type
Pay more than your monthly payment to clear the mortgage faster and pay less interest. Changes here reflect in the chart and table below.
A fixed amount added to every monthly payment.
CURRENT POSITION
Plenty of monthly room — you could absorb meaningful rate rises or life changes without strain.
NEXT BEST MOVE
Move-in Budget tab covers stamp duty, fees, and the buffer you'll want on completion day.
Where to go next
See how prepared you are across deposit, surplus, and the binary readiness factors.
Open readiness summaryHow to read these numbers
You are between 85% and 90% LTV. This can still be workable, but increasing the deposit may improve product choice.
More than 50% of income is left after housing costs. That usually suggests a healthier monthly buffer.
Borrowing range uses gross annual income because lender affordability often starts from gross. Monthly surplus uses estimated take-home pay after Income Tax and employee National Insurance (England, Wales and Northern Ireland rates; Scotland has different income tax bands). Doesn’t account for pension contributions, student loan repayments, or salary sacrifice arrangements.
Lenders also assess income, credit history, debts, commitments, dependants and wider affordability rules. This is a planning guide, not a mortgage offer.
End-of-year balance assuming your interest rate stays the same.
| Year | Remaining debt |
|---|---|
| 0 | £225,000 |
| 1 | £221,680 |
| 2 | £218,191 |
| 3 | £214,523 |
| 4 | £210,667 |
| 5 | £206,615 |
| 6 | £202,354 |
| 7 | £197,876 |
| 8 | £193,169 |
| 9 | £188,221 |
| 10 | £183,020 |
| 11 | £177,552 |
| 12 | £171,805 |
| 13 | £165,764 |
| 14 | £159,414 |
| 15 | £152,739 |
| 16 | £145,722 |
| 17 | £138,347 |
| 18 | £130,594 |
| 19 | £122,444 |
| 20 | £113,878 |
| 21 | £104,873 |
| 22 | £95,407 |
| 23 | £85,458 |
| 24 | £74,999 |
| 25 | £64,005 |
| 26 | £52,448 |
| 27 | £40,301 |
| 28 | £27,532 |
| 29 | £14,109 |
| 30 | £0 |
Owning a home costs more than the mortgage payment alone. This calculator gives a fuller picture of monthly housing costs, but it doesn’t cover every cost of buying or living in a home.
Includes
Does not include
Four levers move your monthly mortgage payment up or down. Adjusting any one of them changes the result.
A higher rate means more interest each month. Even a 1% difference can shift the payment meaningfully on a typical first-time buyer mortgage.
A longer term spreads the loan over more months, lowering each payment but increasing total interest paid over the life of the mortgage.
A bigger deposit lowers the loan amount and the loan-to-value ratio. Lower LTV often unlocks better interest rates.
Repayment mortgages clear the loan over the term; interest-only payments are lower but don’t reduce the loan itself, so you’d still need a repayment plan at the end.
There’s no single right answer, but the percentage of your household income left over after housing is a useful guide:
These are rough guides, not financial advice. Your situation may allow a different balance.
Quick answers to the questions most first-time buyers have when estimating monthly mortgage costs.
Lenders typically offer 4–4.5× combined income, less any fixed monthly commitments. The borrowing range shown here uses both incomes if you enter them. Stress tests, deposit size, and credit history can push the actual figure up or down.
Lenders affordability-test against gross income before tax. Take-home pay still matters for monthly surplus, but the headline “how much can I borrow” figure is gross-driven.
Surplus is what’s left in your bank account after housing — so it has to be calculated from take-home (net) pay, not gross. We deduct Income Tax + National Insurance using current England/Wales/NI bands.
Loan to value (LTV) is the loan amount as a percentage of the property price. £200,000 borrowed on a £250,000 property is 80% LTV. Lower LTV usually unlocks better interest rates.
On a repayment mortgage, your monthly payment is based on the loan amount, the interest rate, and the term length. Each payment covers some interest and some of the loan itself, so the balance reduces over time. Switching to interest-only uses a simpler interest × balance calculation — typical for BTL and short-hold flips.
Use a rate close to what’s currently being offered for the loan-to-value you’re aiming at. Compare a few lender rates or speak to a mortgage broker. Trying a slightly higher rate as well shows how sensitive your figures are to rate changes.
No. This is an estimator to help you plan and compare scenarios. An actual mortgage offer comes from a lender after a full affordability check, credit check, and property valuation.
Running a rental too?
If the exit isn’t a sale — or you’re considering a refinance to BTL hold — the mortgage calculator covers the BTL repayment / interest-only side: monthly payment, stress test, full amortisation.
A focused calculator for UK property flippers and refurb investors. Enter the purchase price, refurbishment budget, holding period, interest rate, and expected resale value (ARV). The tool estimates net profit, ROI on cash, profit margin, annualised return, and the break-even resale price — plus a refinance exit projection at 75% / 80% LTV for buy-and-hold (BRRRR-style) strategies.
This is a screening tool for the financial shape of a deal. It does NOT model: capital gains tax (which applies on sale if not your main residence), corporation tax (if buying through a limited company), VAT on refurb works above threshold, planning permission costs or risk, mortgage eligibility (bridging vs. standard varies), or market-shift risk during the hold period. Always pair with a chartered surveyor’s opinion on ARV, three independent builder’s quotes on refurb, and tax advice for your specific structure.
The most-asked questions UK property flippers run into when screening deals through the numbers.
Buying a property, refurbishing it (often quickly), and reselling it for a profit. The financial model depends on accurate ARV (after-repair-value) estimates, refurbishment budgets with contingency, holding costs (mortgage interest, insurance, council tax, utilities while the property is unoccupied), and selling costs. Returns are typically measured as ROI on cash deployed, profit margin on resale, and annualised return.
Net profit divided by total cash invested in the deal (deposit + refurbishment cost + stamp duty + buying costs + holding costs). It's the single best metric for comparing flips of different sizes — a 20% ROI on £50k cash beats a 5% ROI on £200k cash because the smaller deal recycles capital faster.
Below 5% is poor — you're not being paid for the risk. 5-15% is tight; one cost overrun or market shift turns it negative. 15-30% is workable for an experienced flipper with good processes. 30%+ is strong, but check the ARV assumption — flippers most often over-estimate resale and under-estimate refurb. Margin is sensitive to ARV, refurb cost, and holding period.
Profit margin alone doesn't account for the time the capital is tied up. A 20% flip in 6 months gives a 40%+ annualised return; the same 20% over 18 months gives ~13%. Annualised return is the like-for-like number for comparing a flip against a hold strategy, stocks, or another flip — it normalises for project length.
10% of refurb cost is a sensible default on a property in known condition. 15-20% for older properties, properties with structural unknowns, or first-time flippers. Skimping on contingency is the most common cause of unprofitable flips: a £30k refurb with 0% contingency that goes to £35k turns a 20% margin into a 12% margin overnight.
If you already own another property (your residence or another investment), the additional dwelling supplement applies — currently 5% on top of standard SDLT rates across all bands (as of October 2024). On a £170k flip purchase that's £8,500 just in surcharge. Companies pay 5% on properties over £40k regardless of other holdings. First-time buyer relief does NOT apply to flips.
Bridging finance is faster to draw and works for properties that don't currently meet mortgage-lender criteria (unhabitable kitchens, no working bathroom, structural issues). It's typically 6-12% annualised vs. 5-6% for a standard mortgage, so holding costs increase. For a 4-6 month flip the higher rate may be acceptable; for a 12-18 month flip it can eat the margin. Many flippers use bridging for the purchase + refurb, then refinance to a standard BTL mortgage to hold or to fund the next purchase.
The minimum resale price that recovers your full investment (purchase + refurb + SDLT + buying costs + holding cost + selling costs) at zero profit. Anything below break-even is a loss; anything above is profit. The calculator surfaces this so you know how far the ARV would have to fall before the deal becomes unprofitable — useful for stress-testing against market downturns.
Instead of selling, you refinance the refurbished property at its new higher value, pull cash out, and hold it as a long-term rental. The calculator shows possible cash release at 75% LTV and 80% LTV against the post-refurb value (ARV). This is the BRRRR strategy: Buy, Refurbish, Rent, Refinance, Repeat. Each completed flip recycles capital into the next deal without paying selling costs or capital gains tax (though future rental income is taxable).