Building work estimator
A building work estimator that prices any UK project accurately
A building work estimator turns a set of drawings into a priced, itemised cost for the job. Here is how one works, what it should account for, and how BEX AI builds an accurate estimate for any UK building project in minutes.
What it does
What a building work estimator actually does
A good estimator does more than spit out a number. It builds the number, task by task, from the same inputs a quantity surveyor would use.
Reads the scope
It turns your drawings, dimensions and specification into measured quantities, so every wall, floor and opening is accounted for.
Prices materials and labour
Each task carries a live UK rate for materials, labour hours and plant, so the number is built from the ground up, not guessed.
Adds preliminaries
Site setup, welfare, scaffolding and temporary services, the overlooked costs that quietly sink a lump-sum quote.
Sets a contingency
A costed allowance for the unknowns, 5 to 10 percent on standard work, 10 to 15 percent on complex jobs, so a surprise on site is not a loss on paper.
Breaks it down by phase
Preliminaries to finishes, each stage priced on its own, so nothing hides in a single headline figure.
Outputs a client-ready quote
An itemised, branded document with your VAT number, ready to hand a client or send with a tender.
UK build costs, 2025
What building work costs per square metre
Every estimate starts from a realistic base rate. These are typical UK ranges by project type, before finish level and region are applied.
| Project type | From (per m²) | To (per m²) |
|---|---|---|
| Single-storey extension | £1,800 | £3,200 |
| Double-storey extension | £1,950 | £3,500 |
| Loft conversion | £1,700 | £3,000 |
| New build house | £2,000 | £3,800 |
| Full renovation | £1,200 | £2,500 |
Indicative ranges. Costs vary by finish level and region: London and the South East typically add a 15 to 25 percent premium. All figures exclude VAT.
The BEX AI estimator
From drawings to a priced estimate, in minutes
BEX AI is a building work estimator built for UK builders. You describe the job, it prices it against live rates and returns a full itemised estimate, ready to send. No spreadsheet, no manual take-off.
- 1
Describe the job
Enter the dimensions, layout, plumbing and finish level, or upload your drawings. No spreadsheet, no measuring by hand.
- 2
Generate the estimate
BEX AI prices every phase against live UK rates and builds a full bill of quantities, task by task, in minutes.
- 3
Adjust and send
Refine any line in plain English, swap a finish, add underfloor heating, then export a branded PDF for your client.
Get it right
The mistakes a good estimator stops you making
Most estimating losses trace back to the same handful of gaps. A structured estimator closes them before the job starts.
Incomplete scope
Miss a task at estimate stage and it becomes an argument, or a loss, at invoice stage. A structured estimator forces every element in.
Out-of-date rates
Material prices move quarter to quarter. Pricing off last year's figures quietly erodes the margin on every job.
No contingency
Ground conditions, hidden defects and variations are not exceptions, they are normal. A costed allowance keeps them from becoming losses.
Region ignored
London and the South East carry a 15 to 25 percent premium. A flat national rate misprices half the jobs in the country.
Price your next building job in minutes
Try the BEX AI building work estimator free, or have our estimators prepare one for you from £90.
FAQ
Building work estimator, answered
How accurate is a building work estimator?
A well-built estimate priced against current UK rates typically lands within 3 to 5 percent of final cost, provided the scope is complete and a sensible contingency is carried. Accuracy comes from the quality of the inputs and the rate data, not the tool alone.
Do I need technical knowledge to use one?
No. BEX AI asks for the dimensions, layout and finish level in plain terms and does the measuring and pricing for you. You review the result rather than build it from scratch.
How fast is a digital estimator versus doing it by hand?
Digital workflows cut estimating time by up to 80 percent against manual take-offs. A full extension estimate that takes a day in a spreadsheet is generated in minutes with BEX AI.
Can I get a building estimate prepared for me instead?
Yes. Send your drawings and our estimators prepare an itemised, branded estimate. A Basic Estimate is a flat £90 next working day, Detailed Estimates run £110–£280 by project type. All prices exclude VAT.