L-shaped Cost Calculator
An L-shaped loft conversion in 2026 UK costs £58,000–£95,000 all-in for a typical Victorian/Edwardian terrace or semi with rear addition. London and the South East push the upper end to £110,000+; the North and Midlands often complete around…
Open the calculator →Price l-shaped in 30 seconds
2 steps, using the figures from our cost guide.
How this calculator works
Every figure in this calculator is the one published in the cost table on our l-shaped guide. Pick the option that matches your job and the calculator returns that published range, adjusted for your region - it does not model anything the guide does not already say.
That is deliberate. A calculator whose rates drift from the page it sits under is worse than no calculator, because two numbers on the same site disagree.
What it cannot know: access, the condition of what is already there, and anything structural. Those are what separate three real quotes from each other.
Published l-shaped costs (2026)
| Option | Typical 2026 cost | Notes |
|---|---|---|
| North East / Yorkshire | £52,000–£68,000 | |
| North West / Midlands | £56,000–£75,000 | |
| South West / East | £65,000–£85,000 | |
| Outer London | £72,000–£95,000 |
These are the figures from our l-shaped cost guide.
L-shaped calculator — FAQs
It uses the same published figures as the cost guide it sits under, adjusted for your region. It is a budgeting estimate, not a quote - only a site visit produces one of those.
Related cost guides
- L-shaped cost guide — The full price guide
- All loft conversions services — Browse the hub
- All BestBuilders services — Every trade we cover
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