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Not sure which spec level to choose? Select one level above what the property currently needs. Vendors often underestimate condition; your contractor's first walkthrough usually upgrades the scope.
What You'll Calculate
Four outputs, updated instantly as you adjust your inputs
Refurbishment Works Cost
The base construction cost calculated from your property size, chosen finish level, and regional multiplier. This is the direct contractor cost before any professional fees or contingency buffer is applied.
Professional Fees (12%)
A 12% allowance on top of base works to cover architect fees, structural engineer surveys, planning application costs, and project management. Often the first line removed from investor budgets, and the first cause of serious cost overrun.
Contingency Budget (15%)
A 15% buffer on base works held back for scope changes, hidden defects, and unexpected costs uncovered during works. Standard for light to medium refurbishments. For heavy and extreme renovations, experienced developers typically hold 20%.
Total Project Cost
Refurbishment works plus professional fees plus contingency. This is the all-in figure to present to lenders, JV partners, and your accountant when modelling a deal.
What's Included
Built around how UK refurbishment projects actually work
Covers five finish specifications from Touch Ups (£80/m²) through to Extreme Renovation (£1,500/m²), each with an itemised scope breakdown. Every level specifies exactly which elements are included in kitchen, bathroom, systems, decoration, and flooring, so you can match the right spec to the property's actual condition rather than guessing.
Adjusts all costs for 12 UK regions using calibrated labour and materials multipliers. London sits at 1.55x the UK benchmark; the North East and Northern Ireland sit at 0.90x. The regional multiplier is applied to the base works figure before professional fees and contingency are calculated, so the full output reflects real local pricing.
Adds professional fees (12%) and contingency (15%) automatically to every estimate. These are the two budget lines most consistently excluded by investors when presenting refurbishment numbers, and the two most commonly cited causes of deals going over budget.
How It WorkS
Three inputs, full budget in under a minute
Set your property size
Drag the slider to your property's total floor area in square metres. Use the reference labels on the slider (Studio 30m², Terraced 85m², Detached 150m²+) if you do not have an exact figure. If you are uncertain, use the higher end of your estimate. Refurbishment costs scale directly with floor area.
Select your region
Click your property's region on the interactive UK map. The selected region's multiplier and description appear in the panel beside the map. Multipliers range from 0.90x in the North East and Northern Ireland to 1.55x in London, reflecting real variation in labour and materials costs across the UK.
Choose your finish level
Select the specification that most closely matches the scope of works your property requires. Five levels are available, from Touch Ups through to Extreme Renovation, each with a clear breakdown of what is included. When in doubt, select the higher specification.
Read your total
The summary panel on the right updates instantly. It shows your base refurbishment works cost, professional fees (12%), and contingency (15%) as separate line items, then combines them into a single Total Project Cost figure.
The two budget lines most investors forget
Most investors calculate a refurbishment budget by multiplying floor area by a per-metre rate. That produces the contractor cost, which is only part of the total. A 90m² medium refurbishment in the West Midlands at £450/m² costs £40,500 in base works. The same project with professional fees and contingency properly included costs £51,435. Presenting the £40,500 figure to a lender or a JV partner as the budget is presenting an incomplete number.
Professional fees are not optional on projects with any structural, planning, or mechanical complexity. An architect, a structural engineer on a wall removal, a planning consultant on a change of use, or a project manager on a multi-trade job all cost money. Twelve percent of base works is a standard industry benchmark. Some projects run lower; some run higher. Using zero is the most common planning error in investor refurbishment budgets.
Fifteen percent contingency on base works is an industry standard, not a pessimistic assumption. Established developers hold contingency because refurbishments routinely reveal hidden costs: asbestos, rising damp, structural issues behind plasterwork, outdated electrics that fail an EICR, or timber rot under floors. None of these are visible during a pre-purchase inspection.
On a £40,500 refurbishment, 15% contingency is £6,075. If you finish under budget, you return it to capital. If you hit one unexpected defect, you are already covered. Investors who cut contingency to improve deal metrics on paper are the same investors who return to lenders six weeks into a project asking for additional drawdown.
For heavy and extreme renovations, consider holding 20% rather than 15%. The more structural the scope, the higher the probability of scope change. The 15% in this calculator is a baseline. Projects with roofing, rewires, or significant structural works typically need more.
The gap between the cheapest and most expensive regions in the UK is 72% at the top end. A 90m² heavy refurbishment at £900/m²:
North East or Northern Ireland (0.90x): base cost £72,900 + fees + contingency = £91,773 total
West Midlands (1.00x, UK benchmark): base cost £81,000 + fees + contingency = £101,970 total
London (1.55x): base cost £125,550 + fees + contingency = £158,193 total
The same scope, the same finish standard, a £66,420 difference in total cost between North East and London. If you are applying nationally sourced cost benchmarks to a London deal, or London benchmarks to a northern deal, your budget will be wrong by tens of thousands of pounds.
What each output means in context of your deal
Under £30,000
Light scope, typically fundable from cash reserves. One contractor relationship usually sufficient.
£30k – £80k
Mid-range project. A project manager or regular site visits are worth factoring in.
Over £80,000
Major works. A quantity surveyor and phased drawdown with your lender are advisable.
Standard projects
12% covers architect fees, structural surveys, planning applications, and project management in most cases.
Complex scope
Projects involving wall removals, change of use, loft conversions, or listed building consent may require 15-18% for professional oversight.
Skipped from budget
Removing professional fees to improve deal metrics is the single most common cause of refurbishment projects exceeding the original investor presentation. Budget them in from the start.
Touch Ups to Medium
15% is a standard and sufficient contingency for cosmetic and light structural works where the property has been inspected and major defects are unlikely.
Heavy refurb
Consider holding 20% rather than 15%. Bathroom and kitchen full replacements, boiler and radiator replacements, and full plastering jobs regularly uncover additional work.
Extreme renovation
20-25% is the appropriate contingency range for projects including roofing, full rewires, structural work, or external improvements. Hidden defects in the fabric of the building are almost certain rather than possible.
Under 15% of purchase price
Efficient refurbishment load, well within standard deal viability thresholds used by development finance lenders.
15-25% of purchase price
Acceptable for most deal structures, but GDV assumptions and your exit strategy need to be clearly evidenced before drawing down any finance.
Over 25% of purchase price
High refurbishment-to-value ratio. Scrutinise your GDV assumptions carefully. Lenders and JV partners will apply additional scrutiny at this level.
⚠️ Disclaimer: This calculator provides estimates based on the inputs you enter. Cost per m² benchmarks reflect typical UK market rates and are reviewed periodically, but actual contractor costs vary based on property condition, access, specific scope of works, and individual contractor pricing. Regional multipliers reflect general labour and materials cost differentials and are not site-specific. Always obtain at least two to three competitive contractor quotes before finalising any refurbishment budget. This tool is for planning and educational purposes only and does not constitute financial, professional, or construction advice. Property Filter is not responsible for losses arising from business decisions based on calculator outputs.
Common Questions
How accurate is this refurbishment cost calculator?
The calculator uses industry-standard cost benchmarks per square metre for each specification level, adjusted by verified regional multipliers. For planning and deal analysis purposes, it gives a reliable indicative budget. For live project management, you will need formal contractor quotes. The figure produced here is the starting point for your financial modelling, not a substitute for a schedule of works and competitive tender.
What is included in the 12% professional fees?
Professional fees at 12% of base works covers the range of non-construction costs typically required on a UK refurbishment: architect or designer fees, structural engineer surveys, planning consultant fees (where applicable), project manager costs, and building regulations submissions. On a straightforward cosmetic refurbishment, your professional fees may run below 12%. On a project with planning, structural work, or multiple contractors to coordinate, they can exceed it.
Why does the calculator use 15% contingency?
Fifteen percent is the standard industry benchmark for refurbishment contingency, endorsed by professional bodies including RICS and used widely by development finance lenders when stress-testing investor budgets. It reflects the realistic probability of discovering additional scope during works. Investors who do not include contingency either overspend their stated budget or make decisions mid-project under financial pressure, both of which damage returns.
Which finish level should I select?
Select the level that most closely matches the work the property actually needs. Read the scope breakdown under each level carefully. If the property needs a new kitchen and bathroom as well as full decoration and new flooring throughout, that is a Medium Refurb. If it additionally needs a new boiler and radiators and full replastering, that is a Heavy Refurb. When the property is on the boundary between two levels, choose the higher one. Scope always expands on inspection; it rarely contracts.
How do regional cost differences work?
The calculator applies a multiplier to the base works figure to reflect real variation in labour and materials costs across the UK. The Midlands is the national benchmark (1.00x). London is 55% more expensive (1.55x). The North East and Northern Ireland are 10% below benchmark (0.90x). These multipliers reflect the typical differential between regions based on trade labour rates and supply chain costs, not any specific postcode or site. Use them as a directional adjustment, then sense-check against local contractor quotes.
What is not included in the estimate?
The calculator covers on-site refurbishment works, professional fees, and contingency. It does not include purchase costs (stamp duty, legal fees, mortgage arrangement fees), holding costs during the refurbishment period (mortgage interest, council tax, utilities), void costs before the property is re-let, or any planning and building regulations fees charged directly by the local authority. Use Property Filter's Stamp Duty Calculator and BRRR Deal Calculator alongside this tool for a full deal picture.
What is the difference between Heavy Refurb and Extreme Renovation?
Heavy Refurb (£900/m²) covers a full kitchen replacement with appliances, a full bathroom suite replacement including plumbing, a new boiler and radiators, full plastering and decoration, and new flooring throughout. Extreme Renovation (£1,500/m²) adds complete roofing, new windows and UPVC doors, a full electrical rewire with new consumer unit, and external works including gutters, fencing, and outdoor tidy. If the property is habitable but tired, Heavy Refurb is likely the right level. If it is derelict, partially roofless, or has condemned electrics, Extreme Renovation applies.
Can I use this calculator for HMO refurbishments?
Yes, though HMO refurbishments typically carry additional costs not captured here. Fire doors, fire detection systems, emergency lighting, and any HMO licensing works required to meet your local authority's HMO management standards add cost on top of the base refurbishment spec. For a standard HMO conversion, add a further £3,000-6,000 to the total estimate depending on the number of rooms and current fire safety compliance of the property. Use the HMO Valuation Calculator alongside this tool when analysing HMO deals.
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