Inputs
Pattern adds joint length.
Approximate defaults—confirm with the product datasheet.
Area Mode
m
m
m²
Tile & Joint
mm
mm
mm
mm
Often ~ two-thirds of tile thickness.
%
Mosaic Sheet Helper
mm
mm
If set, you can auto-fill total area.
Material Density & Packaging
Equivalence: —
Comma-separated, e.g., 5,10,25
Comma-separated, e.g., 10,25,50
Results
Grout volume
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—
—
Grout mass
—
—
—
Recommended packaging
rounded up
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Project Rooms
Aggregate multiple rooms and export totals. Stored locally.
| # | Name | Area (m²) | Volume (L) | Mass (kg) |
|---|
Project totals
use current bag sizes
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Example Data
| # | Area Mode | Room Length | Room Width | Total Area | Tile L×W | Joint Width | Depth | Pattern | Waste |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Dimensions | 5 m | 4 m | — | 300×300 mm | 3 mm | 6 mm | Straight | 10% |
| 2 | Total area | — | — | 50 m² | 600×600 mm | 3 mm | 6 mm | Diagonal | 8% |
Formula Used
Total grout volume approximates joint cross-section times total joint length:
Let:
A = area (m²)
a = tile length (m) b = tile width (m)
g = joint width (m) d = grout depth (m)
pitch_x = a + g pitch_y = b + g
λ = (1 / pitch_x) + (1 / pitch_y) (joint length per area, m per m²)
P = pattern factor (e.g., 1.00 straight, 1.05 diagonal)
w = waste fraction (e.g., 0.10)
Base volume (m³) without perimeter:
V_base = A × g × d × λ
If room dimensions are known and perimeter joints are included:
V_perimeter = (2 × (L + W)) × g × d
V_total = (V_base + V_perimeter) × P × (1 + w)
Otherwise (area-only mode):
V_total = V_base × P × (1 + w)
Mass:
mass_kg = V_total × ρ (kg/m³), with ρ = 1000 × density_kg_per_LHow to Use
- Pick units, pattern, and optionally a brand preset.
- Choose area mode and enter room dimensions or total area.
- Enter tile size, joint width, depth, and waste percentage.
- Use mosaic helper to derive chip size or total area from sheets.
- Click Calculate for results. Add rooms to your project.
- Export CSV/PDF for a room or for the whole project as needed.
FAQs
They are approximate examples. Always confirm density, bag sizes, and coverage
with the specific grout’s official datasheet before purchasing.
Provide sheet size and chip counts. The tool estimates chip size by subtracting
joints between chips and sets tile dimensions accordingly. You can also use sheet
count to auto-fill total area.
Perimeter can be significant in small rooms. Include if grouting to edges.
If using caulk or movement joints at perimeters, leave unchecked.
Non-straight layouts increase joint length slightly. The multipliers approximate
that increase for running bond and diagonal/herringbone layouts.
Projects save to your browser’s local storage. You can export JSON to share or
archive and import it later to restore the rooms.
Coverage charts are helpful but depend on tile and joint geometry.
This calculator models geometry directly and lets you tune product variables.