Grout Volume
Estimate grout from tile size, joint width, joint depth, and tiled area.
About this calculator
This calculator reduces to a clean identity once you cancel the millimeter-to-meter conversions in its own math: Grout volume = Area x Joint x Grout depth x (1/Tile length + 1/Tile width). Area, Joint width, and Grout depth all enter as a straight product, so each one scales the result by exactly the same proportion -- doubling any one of them doubles the grout volume, and this holds everywhere across their declared ranges, not just near the default. Tile length and tile width work the opposite way: because the formula sums their reciprocals, a LARGER tile always means LESS grout, since fewer, wider joints are needed to cover the same area.
A 600x300mm tile and a 300x300mm tile at the same area, joint, and depth do not use the same grout -- the more elongated tile has a smaller (1/L + 1/W) term. This engine estimates joint length from tile count and perimeter, so it is a planning estimate, not a substitute for a manufacturer's coverage chart; irregular cuts, waste, and uneven substrates are not modeled and will increase real-world consumption above this figure.
Inputs
Results
Grout volume
1.44 L
≈ 4 soda cans
How to Use This Calculator
- Enter the tile length and width in millimeters from the tile specification sheet.
- Enter the grout joint width in mm — the spacer size you are using (e.g., 3 mm).
- Enter the grout depth in mm — typically 4 mm below the tile surface edge.
- Enter the total tiled area in square meters.
- Read the grout volume in liters and the number of approximately 5 L bags to purchase.
How the result changes with Joint (mm)
| Joint (mm) | Grout volume |
|---|---|
| 1.5 | 0.72 L |
| 2.25 | 1.08 L |
| 4.5 | 2.16 L |
| 7.5 | 3.6 L |
What each input means
- Tile length (mm)
- Length of a single tile in millimeters. Common sizes: 300, 600, 900 mm.
- Tile width (mm)
- Width of a single tile in millimeters. For square tiles, enter the same value as length.
- Joint (mm)
- Spacer width.
- Grout depth (mm)
- Below edge.
- Area (m²)
- Total area to be tiled in square meters. Measure the floor or wall surface.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersTile length (mm) = 600, Tile width (mm) = 300, Joint (mm) = 3, Grout depth (mm) = 4 = 5 input(s) provided
- Calculate Grout volumeGrout volume1.44 = 1.44
Engine last updated . Checked against 4 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does grout volume scale directly with tiled area?
The engine multiplies area, joint width, and grout depth together with no diminishing effect, so every square meter you add requires the same additional grout as the last one. Doubling the Area input exactly doubles both Grout volume and the bag count, at any point across the 1 to 100,000 square meter range.
Why does grout volume go DOWN when I use a bigger tile?
Larger tiles need fewer joints to cover the same area, and the calculator's formula reduces to Area x Joint x Depth x (1/Length + 1/Width) -- so growing either tile dimension shrinks that reciprocal term and lowers the result. A 900mm tile uses noticeably less grout than a 300mm tile of the same thickness and joint width over an identical floor area.
Does the joint width or the grout depth matter more?
Neither one dominates -- both are pure linear multipliers in the volume formula, so a 10% change in Joint (mm) and a 10% change in Grout depth (mm) move the result by the identical percentage. Treat them as equally important when estimating your bag count.
How accurate is the bag count for purchasing?
The ~5 L bags figure divides the computed grout volume by 5 liters per bag, which assumes full, undamaged bags and does not add a waste allowance. Order slightly more than the calculated figure to cover mixing loss, uneven joints, and future repairs.
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