Skylight Calculator
Calculate skylight and roof lantern costs, sizes and thermal performance for fixed, opening, dome and lantern skylights with Part L U-value checking.
How We Calculate This
This calculator estimates skylight costs based on type, size, glazing and quantity.
The formula
Total = (Unit Price × Size Factor × Glazing Multiplier × Qty) + Kerb Kits + Installation
- Base prices vary by skylight type
- Size factor increases for units over 1 m²
- Triple glazing adds ~35% to unit cost
- Daylight gain = Area × 3 (vs vertical glazing)
Frequently Asked Questions
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Last updated: March 2026
All calculations are estimates. Verify with your supplier.