Free tools · no sign-up · no sales call
The numbers builders
don't show you.
The same cost models, building physics and legal rules behind our paid reports — opened up, free. Budget your project, test your walls for mould and serve your party wall notice before you spend a penny.
- 30 sec
- to a London budget
- 48 h
- to a fixed Home Art price
- 5%
- below your best quote, guaranteed
Live London budget
2026 pricesAll-in, inc. VAT
£24k–£41k
3–5 weeks
on site
Units · fitting · plumbing · electrics · tiling · decoration · contingency
Get it fixed in 48 hFive tools, one goal
Walk into every builder conversation knowing more than they expect.
Each tool takes under two minutes. Email yourself the result, or take it straight into a Quote Check.
Extension cost calculator
Know the real number before a builder names one.
- ✓Every line: build, design, engineer, party wall
- ✓Standard, mid or high-end spec
- ✓Inner, outer or central London pricing
Kitchen & bathroom cost calculator
A new kitchen or bathroom, priced in 30 seconds — fixed in 48 hours.
- ✓Kitchen, bathroom, en-suite or WC
- ✓Standard, mid or high-end finish
- ✓Turn it into a fixed Home Art price
Loft conversion cost calculator
Dormer, mansard or rooflights — priced properly.
- ✓All-in budget incl. fees and contingency
- ✓Programme length on site
- ✓Planning route for each loft type
12.3°
Dew point
11.1°
Wall
100%
Surface RH
Condensation & mould risk calculator
Find out if your walls will grow mould this winter.
- ✓Dew point and wall surface temperature
- ✓The exact humidity that keeps mould away
- ✓Solid brick, cavity or insulated walls
Party Structure Notice
Party Wall etc. Act 1996 · Section 3
Party wall notice generator
Skip paying a surveyor just to write the letter. Serve it yourself, correctly.
- ✓Section 1, 3 and 6 notices
- ✓Lawful start date calculated
- ✓Neighbour reply form attached
From free number to fair price
Most homeowners overpay because they start with the builder. Start here instead.
- 01Free
Budget it
Use the calculators to know what your project should cost — every fee included.
Go - 02from £149
Check the quotes
Upload up to three builder quotes. We level them, flag what is missing and what is overpriced.
Go - 03Guaranteed
Beat it by 5%
Home Art Build prices the same scope at least 5% below the strongest quote — or your Quote Check is free.
Go
Got a builder's quote? We'll beat it by 5%.
Send us any written, itemised quote for your project. We compare it like-for-like — adding back everything it leaves out — then Home Art Build prices the same scope at least 5% lower. If we can't, your Quote Check fee is refunded in full.
- 1
Upload your quotes
Up to three, any format. Quote Check reads every line.
- 2
We level them
Missing items are priced in so you compare like with like.
- 3
We beat the best by 5%
A fixed-price Home Art Build quote after a free site visit.
Questions
Free means free.
No account, no card, no follow-up calls. If you email yourself a result we send that result — and nothing else unless you ask.
How accurate are the cost calculators?+
They use 2026 London rates by project type, specification and location, plus every fee a real project carries. They are budgeting ranges, not quotes — ground conditions and your exact spec move the final price. A Quote Check tells you whether a real quote is fair.
Why are these free?+
Because homeowners who understand their numbers make better clients. Some will want a Quote Check or a Home Art Build quote later; most won't, and that is fine.
Is the party wall notice legally valid?+
It follows the Party Wall etc. Act 1996 and calculates the correct notice period. You still need to serve it on every adjoining owner and keep proof of delivery. It is a template, not legal advice.
Do you store what I enter?+
Only if you choose to email yourself a result. Homeart Construction & Real Estate Ltd never sells or shares your details.