What spacing should main runners be at?

Main runners are spaced at 1200mm centres for both 600×600mm and 600×1200mm tile modules. The runners usually run along the length of the room. They are suspended from the structural ceiling/soffit above using drop wires or adjustable hangers at maximum 1200mm centres along each runner.

What is the difference between main runners and cross tees?

Main runners are the primary load-bearing members running the full length of the room at 1200mm centres. Cross tees are shorter sections that slot into the main runners at right angles to form the grid. 1200mm cross tees connect between main runners, and 600mm cross tees subdivide 1200mm bays for 600×600 tiles. For 600×1200mm tiles, only 1200mm cross tees are needed.

How many suspension wires do I need?

Suspension wires (or adjustable hangers) should be at maximum 1200mm centres along each main runner, and within 300mm of each wall. For a 4m × 3m room with main runners at 1200mm centres (3 rows), you would need approximately 12-15 suspension wires. Each wire must be securely fixed to the structural ceiling above using appropriate fixings.

What is wall angle trim?

Wall angle (also called perimeter trim or L-trim) is an L-shaped metal trim fixed around the entire perimeter of the room at the desired ceiling height. It supports the grid edge tiles and provides a neat finish where the ceiling meets the walls. It comes in 3m lengths and is fixed to the wall at approximately 450mm centres using screws and rawlplugs.

Should I use 600×600 or 600×1200 ceiling tiles?

600×600mm tiles are the most common in the UK and are easier to handle (lighter, less likely to sag). 600×1200mm tiles are more common in commercial settings and create fewer grid lines for a cleaner look. Both modules use 1200mm main runner spacing. 600×600 requires additional 600mm cross tees to subdivide each 1200×600mm bay. Choose based on visual preference and tile availability.

Ceiling Grid Calculator — Runners, Tees, Wires & Tiles

Calculate suspended ceiling grid components: main runners, cross tees, wall angles, suspension wires and ceiling tiles for 600×600 or 600×1200 modules.

Room Length

Direction main runners will run

Room Width

Perpendicular to main runners

Tile Module

600×600 is most common in the UK

Main Runner Price (optional)

Per 3.6m main runner

Cross Tee Price (optional)

Per 600 or 1200mm cross tee

Wall Angle Price (optional)

Per 3m wall angle

Wire/Hanger Price (optional)

Per suspension wire/hanger

Tile Price (optional)

Per ceiling tile

How We Calculate This

This calculator determines all the components needed for a suspended ceiling grid system based on your room dimensions and chosen tile module.

The formula

Main runners = Room width ÷ 1200mm + 1 (rows)

Cross tees (1200mm) = (Runner rows − 1) × Bays along length

For a 6m × 4m room: main runner rows = 4000 ÷ 1200 + 1 = 5. Runner lengths = 5 × 6m = 30m (9 × 3.6m). Cross tees 1200mm = 4 × 5 = 20. Cross tees 600mm (for 600×600): 20. Tiles = 7 × 10 = 70.

Standard grid spacing

Main runners: 1200mm centres
Cross tees: 600mm intervals along main runners
Suspension wires: 1200mm max along each runner
Wall angle: Full room perimeter

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.