Pick your project below and get the realistic 2026 fitted price range — built from the same verified trade data as our full cost guide. It’s an estimate for budgeting, not a quote: real prices move with roof condition, access and how busy your local fitters are.
Skylight cost calculator
How the estimate is built (methodology)
Every number comes from the 2026 UK cost data verified for our guides — chiefly MyJobQuote’s June 2026 cost guide and BookaBuilderUK’s 2026 figures, the same sources behind our skylight installation cost guide and VELUX price guide:
- Roof windows: fitted ranges by size span manual centre-pivot (cheapest) to top-hung in upgraded finishes — £655 small to ~£1,195 large; medium sizes are interpolated between the verified small/large anchors.
- Powered opening (electric or solar): +£300–£800 by size and spec.
- Replacement into an existing opening: £500–£800 — the structural work already exists.
- Flat-roof skylights £1,000–£3,000, roof lanterns £2,000–£5,000+ (large/bespoke exceeds it), sun tunnels £500–£1,200, all fitted.
- Scaffolding £400–£1,200 — the swing item; “not sure” keeps it in the upper bound only.
- London & South East: +15%, reflecting that the capital sits at the top of every national range.
What the calculator deliberately doesn’t include: structural steel for oversized openings, bespoke glazing (project-priced), interior decoration beyond basic making-good, and blinds — budget those separately.
Using the number
Treat the range as your budgeting envelope, then make quotes comparable: same window spec and size code on every quote, access/scaffolding itemised, flashing included, and building-regs sign-off confirmed (how that works). If quotes land far outside the calculator’s range, that’s your cue to ask why — sometimes it’s a genuinely awkward roof; sometimes it’s a fitter who doesn’t want the job pricing you away.
Frequently asked questions
How accurate is this skylight cost calculator?
It returns the realistic fitted range for your configuration based on 2026 UK trade cost guides — not a quote. Real quotes vary with roof condition, access and local rates, which is why the output is a range and why you should still get three itemised quotes.
Why does scaffolding change the estimate so much?
Because it's the swing item on real jobs: £400–£1,200 before a tile moves. Windows that can be fitted from inside the loft avoid it entirely — always ask installers whether their quote includes access.
Why is London more expensive for skylight installation?
Higher labour rates and more frequent access complications (terraces, parking, conservation streets) put London and the South East at the top of every national range — roughly 15% above typical UK pricing.
What's the cheapest way to get a skylight fitted?
A like-for-like replacement into an existing opening (£500–£800) — the structural work already exists. For new openings, a small manual roof window fitted from inside, avoiding scaffolding, starts around £650.
Keep reading
Bespoke rooflights cost £1,000–£4,000+ supplied versus a few hundred for standard sizes. When made-to-measure is worth it — and when it isn't.
Most UK skylight installations cost £900–£2,500 per window in 2026, fully fitted. Full breakdown: supply, labour, scaffolding, flat roofs and lanterns.
Fakro, Keylite, RoofLITE+, Roto and Dakea compared against VELUX on 2026 prices, guarantees and quality — and which alternative fits which job.