Home & DIY calculator

Grout Calculator

Estimate grout from tile dimensions, joint width and installation area.

Example with the pre-filled values

Estimated grout (kg): 2.3 · Grout to buy, rounded up (kg): 3

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Enter your details, then calculate.

Your answer and the practical quantities behind it will appear here.

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How the Grout Calculator works

Formula

Grout (kg) = tiled area (m²) × (tile length + tile width) ÷ (tile length × tile width) × joint width × joint depth × 1.6, with tile and joint sizes in millimetres.
The purchase figure rounds up to the next whole kilogram; no waste allowance is added.

Assumptions and limits

Uses a planning density of 1.6 kg/L; tile profile and waste affect actual use.

Worked example

For 12 m² of 600 × 300 mm tiles with 3 mm joints 8 mm deep: (600 + 300) ÷ (600 × 300) × 3 × 8 × 1.6 × 12 ≈ 2.3 kg of grout, so buy 3 kg.

Pre-filled values
Input	Value
Tiled area	12 m²
Tile length	600 mm
Tile width	300 mm
Joint depth	8 mm
Joint width	3 mm

Calculated result
Result	Value
Estimated grout (kg)	2.3
Grout to buy, rounded up (kg)	3

Reading the result

Joint depth normally equals tile thickness, so thicker tiles use more grout at the same joint width.
Small mosaic tiles have far more joint length per square metre and use much more grout.
Check the density on your grout bag; 1.6 kg per litre is a planning figure, and some epoxy grouts differ.

Your measurements and assumptions

Use the actual product label and your measured quantities. Starting values are editable examples, not universal rates or product specifications. Keep the units beside each input.

manufacturer_formula or measured joint_volume * entered_product_density; state units

Tile width/length/thickness, joint width, area, product consumption/density and whole bag rounding.
Do not apply one grout density to all products. Quote manufacturer consumption chart or label default assumption.

Change the inputs to match your own task. Whole packages are rounded up after allowances, so purchase quantity and actual requirement can differ. Apply each allowance once.