How much grout do I need per square metre?

It depends on tile size, joint width and tile thickness — smaller tiles and wider joints use more grout. As a rough guide, 300 mm floor tiles with a 3 mm joint use roughly 0.5 kg/m². The estimator computes the exact figure from your inputs above.

How much tile adhesive do I need?

This estimator assumes about 4 kg/m² at a 6 mm notched trowel, then rounds up to whole 20 kg bags — so one bag covers roughly 5 m². Large-format tiles and uneven substrates need a bigger trowel and more adhesive.

How do I calculate how many floor tiles I need?

Divide the floor area (with wastage added) by the face area of one tile, then round up. A 20 m² floor of 300 × 300 mm tiles (0.09 m² each) at 10% wastage is about 245 tiles. The calculator handles the rounding.

How much wastage should I allow for floor tiles?

10% for a straight-lay grid with rectified tile. Diagonal, brick-bond, mosaic and large-format layouts push it to 15% or more because of extra perimeter cuts and breakage.

How is the grout quantity calculated?

From the joint volume per square metre: ((tile length + tile width) × joint width × tile thickness) ÷ (tile length × tile width), multiplied by a grout density of about 1.6 g/cm³ for typical cementitious grout.

AreaSum

Free tool

Tile and grout estimator

Enter floor area, tile size, joint width and wastage. The calculator returns the tile count, adhesive bags and grout kilograms.

Inputs

Floor area

m²

Tile length

Tile width

Grout joint

Tile thickness

Wastage

10% covers straight-lay rectified tile. Diagonal, mosaic and large-format installs run higher.

Result

Tiles to order62Whole tiles, wastage applied.

Adhesive4 × 20 kg

Grout2.56 kg

Adhesive assumes 4 kg/m² with a 6 mm notched trowel. Grout is calculated from tile size, joint width and thickness at a typical cementitious density (1.6 g/cm³). Confirm against the spec on your supplier's technical data sheet.

How the calculation works

Tile count is the area (with wastage applied) divided by the tile face area, rounded up to a whole tile. Adhesive assumes 4 kg/m² coverage at a 6 mm notched trowel; we round up to the next 20 kg bag. Grout kilograms are calculated from the joint volume per square metre — ((tile length + tile width) × joint width × tile thickness) divided by (tile length × tile width), multiplied by a density factor of 1.6 (typical cementitious grout).

For multi-room jobs (bathrooms, ensuites and living areas in the same project), mark each room from a PDF plan in AreaSum and the report rolls totals up per material so adhesive and grout figures stay accurate. See how it works.

See also: wastage allowance, linear metres — or the audience guide for tile installers.

Tiles, adhesive & grout — frequently asked questions

How much grout do I need per square metre?: It depends on tile size, joint width and tile thickness — smaller tiles and wider joints use more grout. As a rough guide, 300 mm floor tiles with a 3 mm joint use roughly 0.5 kg/m². The estimator computes the exact figure from your inputs above.
How much tile adhesive do I need?: This estimator assumes about 4 kg/m² at a 6 mm notched trowel, then rounds up to whole 20 kg bags — so one bag covers roughly 5 m². Large-format tiles and uneven substrates need a bigger trowel and more adhesive.
How do I calculate how many floor tiles I need?: Divide the floor area (with wastage added) by the face area of one tile, then round up. A 20 m² floor of 300 × 300 mm tiles (0.09 m² each) at 10% wastage is about 245 tiles. The calculator handles the rounding.
How much wastage should I allow for floor tiles?: 10% for a straight-lay grid with rectified tile. Diagonal, brick-bond, mosaic and large-format layouts push it to 15% or more because of extra perimeter cuts and breakage.
How is the grout quantity calculated?: From the joint volume per square metre: ((tile length + tile width) × joint width × tile thickness) ÷ (tile length × tile width), multiplied by a grout density of about 1.6 g/cm³ for typical cementitious grout.