# Ceiling Grid Calculator

Main and cross runner lengths, hangers and fittings from ceiling size.

- Page: https://jianzhujisuan.com/en/ceiling-grid
- Category: Finishes (https://jianzhujisuan.com/en/c/finishes)
- Chinese version: https://jianzhujisuan.com/zh/ceiling-grid.md
- Data checked: 2026-10-25

## Quick result

With the default inputs (Ceiling length 6 m, Ceiling width 4 m, Main runner spacing 1.2 m, Cross tee spacing 0.4 m, Hanger spacing 1.2 m, Waste 5%): **Main runner 21.0 m**

## Inputs

| Parameter | Type | Default | Unit | Note |
|---|---|---|---|---|
| Ceiling length | number | 6 | m |  |
| Ceiling width | number | 4 | m |  |
| Main runner spacing | number | 1.2 | m | Usually 0.9-1.2 m |
| Cross tee spacing | number | 0.4 | m | 400 mm for plasterboard, 300 mm for strip ceilings |
| Hanger spacing | number | 1.2 | m | Not more than 1.2 m, within 300 mm of runner ends |
| Waste | number | 5 | % |  |

## 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)

## Worked example

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.

## Questions

### 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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Generated by BuildCalc. All calculations run in your browser; no data is uploaded. Formulas follow national standards and common trade practice; local codes govern.