Ceiling Grid Calculator
Main and cross runner lengths, hangers and fittings from ceiling size.
Inputs
Result
Formula
| Area | A = length × width |
| Main runner | L = A ÷ spacing × (1 + waste) |
| Cross tees | L = A ÷ spacing × (1 + waste) |
| Perimeter | L = 2 × (length + width) × (1 + waste) |
| Hangers | N = (floor(L÷s)+1) × (floor(W÷s)+1) |
A 6 × 4 m ceiling with 1.2 m main runners, 0.4 m cross tees and 1.2 m hangers at 5% waste: 24 m², 21.0 m of runner, 63.0 m of cross tee, 21.0 m of trim and 24 hangers.
FAQ
Main runner versus cross tee?
Main runners carry the load directly from the hangers, have the larger section and run parallel to the short side; cross tees clip underneath and support the boards, their spacing setting the board span. Main spacing follows the hanger layout (within 1.2 m), cross spacing follows board strength (400 mm for plasterboard). Swap them and the ceiling sags.
Why cap hanger spacing at 1.2 m?
Main runners deflect under their own weight and the boards; wider spacing turns them into long simply-supported spans that sag in the middle and crack at the joints. The code caps spacing at 1.2 m and requires support within 300 mm of runner ends, since an overhanging end sags first. Heavy items like luminaires need their own hangers.
What is typical grid content per m²?
For a normal plasterboard ceiling: about 0.9-1.1 m/m² of main runner, 2.5-2.8 m/m² of cross tee and roughly 0.8 m/m² of perimeter trim, less in larger rooms. Calculating is more reliable than rules of thumb because small rooms carry proportionally more trim.
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Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.