Grout Calculator — How Many Pounds of Grout Do I Need?
Enter your tile size, joint width and area to get grout in pounds, with 10% waste built in. No sign-up, no data stored.
Grout needed
How grout quantity is estimated
- Joint length per sq ft = 2 / (tile width / 12) + 2 / (tile length / 12) — the seams between tiles in one square foot.
- Grout volume (cu ft) = joint length x joint width x tile thickness / 1728.
- Grout weight = volume x 120 lb per cu ft (typical sanded grout density), times the tile area.
- Waste = +10% default for mixing loss and slightly wide joints; change it if your joints run wider.
Small mosaic tiles double or triple the joint length, which is why a 50-lb bag lasts a 500-sq-ft floor with 12x12 tile but only about 100 sq ft of 2x2 mosaic. Match the bag size to the surface you're actually tiling.
Tile size → grout coverage reference
Approx. grout pounds per 100 sq ft, 1/8-in joints, 1/4-in thick tile, +10% waste.
| Tile size | Grout per 100 sq ft | 50-lb bag covers |
|---|---|---|
| 2x2 mosaic | ~55–60 lb | ~90 sq ft |
| 4x4 | ~25 lb | ~200 sq ft |
| 6x6 | ~17 lb | ~300 sq ft |
| 12x12 | ~8–9 lb | ~560 sq ft |
| 12x24 | ~6 lb | ~830 sq ft |
Last updated: October 2026 · Estimates use sanded-grout density about 120 lb/cu ft at 1/8-in joints. Grout formulas vary by brand — check the coverage label on the bag.
Grout FAQ
With 12x12 tile and 1/8-in joints, about 8–9 lb (plus waste). With 6x6 tile it's closer to 17 lb, and 2x2 mosaic jumps to 55 lb+ — the smaller the tile, the more grout line.
You risk a visible color mismatch if the next batch mixes differently. Mix all of one batch for the whole floor, or buy one full bucket more than the estimate.
No — joints should be uniform width, not vary with tile edges. Use spacers sized to your joint and keep them consistent across the whole surface.
Use sanded for floors — unsanded lacks strength for foot traffic and cracks in wide joints. Unsanded is best for walls, glass and joints under 1/8 in.
Standard wall tile is 1/4 in, most floor tile 3/8 in, and large-format porcelain 1/2 in or more. Measure one tile — thickness changes the grout volume directly.
Related calculators & guides
How Much Grout Do I Need?
The joint-length formula, sanded vs unsanded, and coverage tables for every common tile size.
Read the guide →