Attic conversion Cost Calculator
In UK building terminology, "attic conversion" and "loft conversion" aren't synonyms — they're at opposite ends of the same spectrum. A loft conversion converts an unused roof space into habitable rooms. An attic conversion (the term builders use for the higher-spec end) usually implies a fuller…
Open the calculator →Price attic conversion 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 attic conversion 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 attic conversion costs (2026)
| Option | Typical 2026 cost | Notes |
|---|---|---|
| Velux loft (rooflights only) | £22,000–£38,000 | |
| Dormer loft conversion | £35,000–£60,000 | |
| Hip-to-gable loft conversion | £45,000–£70,000 | |
| Attic conversion (dormer + en-suit | £45,000–£70,000 | |
| Mansard attic conversion (ridge ra | £2,500–£3,400 |
These are the figures from our attic conversion cost guide.
Attic conversion 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
- Attic conversion cost guide — The full price guide
- All loft conversions services — Browse the hub
- All BestBuilders services — Every trade we cover
Get 3 Free Quotes
60 seconds · No spam · No obligation