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Your calculation audit
Every total is shown as a short sequence so you can see what was measured, deducted, adjusted and rounded.
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Tiling
Grout calculator
Estimate tile joint volume, approximate grout weight and rounded bags from tile and joint dimensions.
Transparent formulaFormula v1.0 · tile joint geometry × surface area × density × waste allowance
Scope boundary: Approximate grout quantity only — tile edge, joint profile, mix, cleaning and product coverage can change actual use.
Measure clearly
Simple guidance
Measure the finished tiled area and use the actual tile width and height. Enter the joint width and the depth you expect to fill, then keep the density value visible when comparing the result with your chosen grout product.
Worked example
Follow the same logic
An 8 m² surface with 600 × 300 mm tiles, 3 mm joints and 8 mm joint depth has about 0.96 L of joint space. At the displayed 1.6 kg/L density, that is about 1.54 kg before a 10% allowance and rounds to one 5 kg bag.
Planning tipWrite down the product factor or pack size you used, so a later change is easy to trace.
Before you buy
Three quick checks
- 01
Use actual tile dimensions rather than a nominal tile name.
- 02
Enter the expected joint width and grout fill depth separately.
- 03
Check the selected grout's coverage, colour and bag size before buying.
Quick answers
Useful to know
Why do tile and joint sizes matter?
Smaller tiles or wider and deeper joints create more joint run and volume over the same area. Those dimensions have a direct effect on the estimate.
Is this an exact grout quantity?
No. It is a visible geometric planning estimate. Tile edge profile, joint profile, mixing, cleaning and the product itself can change actual use.
Review record
Transparent calculation method
Last reviewed: 2026-10-17. Formula version: v1.0. Classification: grout quantity estimate.
Formula source: src/calculator.js. Uses visitor-entered measurements and product values.