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Roof Lantern Size Calculator
Find the ideal roof lantern dimensions for your room. Enter your ceiling area, roof pitch, and glazing type to get recommended sizes, ridge height, and natural light coverage.
☀️ Natural light estimate
📐 Pitch & ridge height
⚡ Instant results
🏗️ Extensions & orangeries
Roof Lantern Calculator
Enter your room and roof details below
Room Dimensions
m
m
Internal dimensions of the room receiving the lantern
Lantern Specification
Steeper pitches increase ridge height and glazed area
Affects light transmission and thermal performance
Kerb & Ceiling
mm
m
Upstand is the frame that sits above the flat roof before the glazing begins
Lantern Recommendations
Dimensions, light coverage & ridge height
Enter your room dimensions and roof details, then click Calculate to see the recommended lantern size and performance figures.