Greenhouse Panel Area Calculator
Calculate gross wall and roof area for a simple gable envelope, before ordering panels or estimating heat loss.
Your planning estimate
Enable JavaScript to run this calculator. The formula and assumptions are available below.
How this tool works
A geometric envelope estimate for a symmetric gable, not a panel cutting schedule. Door and vent openings remain included in gross area. The allowance is shown separately so it cannot be mistaken for actual surface area.
Roof = 2L × √[(W/2)² + (ridge − eave)²]. Walls = 2Leave + 2Weave + W(ridge − eave). Floor excluded.
What this estimate does not tell you
Sheet dimensions, flute direction, manufacturer expansion clearances, trimming and reuse of offcuts govern real material orders. Do not use this straight-roof model for curved, hoop, bell-shaped, lean-to or T-shaped structures. Confirm the exact replacement-panel schedule for a commercial kit.