Tile Grout Calculator
Work out exactly how many pounds and bags of grout a tiled area needs, using the standard published coverage formula rather than a rough rule of thumb. Add your own price for a full cost estimate — nothing here uses a stale national average.
How this calculator works
This uses the standard published grout coverage formula, rather than a generic rule of thumb — it accounts for tile size, joint width, joint depth and area directly:
grout_lbs = ( (tile_length_in + tile_width_in) / (tile_length_in × tile_width_in) )
× joint_width_in × joint_depth_in × area_sqft × density_factor
// density_factor: ≈105 for sanded grout, ≈128 for unsanded groutJoint depth is the one input this formula needs that a simpler lookup table would hide — it commonly equals your tile's thickness, since grout typically fills the joint from the tile surface down to the substrate. That's why it's editable here rather than assumed.
Worked example
200 sq ft of 12 in × 12 in tile, 1/8 in joint width, 3/8 in joint depth, sanded grout:
- Tile ratio: (12 + 12) ÷ (12 × 12) = 0.1667.
- Grout: 0.1667 × 0.125 × 0.375 × 200 × 105 ≈ 164 lb.
- Bags at 25 lb each: ceil(164 ÷ 25) = 7 bags.
The same job in unsanded grout with a narrower 1/16 in joint (typical for unsanded) needs about 100 lb, or 4 bags — showing how joint width and grout type interact rather than grout type alone driving the difference.
Measuring your job
- Area — use your total tiled square footage, same figure you'd use for ordering tile.
- Tile size — measure the actual tile, not the box label if they differ.
- Joint width — check your design or the tile manufacturer's spacer recommendation.
- Joint depth — usually equals tile thickness; check your specific tile's spec sheet.
How much does grout cost?
Rather than quoting a national average that's stale the day it's published, this calculator prices the job from what you actually enter. Give a bag weight and price per bag, and it's converted straight through from the calculated pounds needed. The estimate doesn't include grout sealer or float/sponge tools.
Frequently asked questions
Sanded vs unsanded grout — when should I use each?
Unsanded suits narrow joints, typically under 1/8 in, and scratch-sensitive polished stone. Sanded suits joints 1/8 in and wider, common on floor tile, since the sand adds strength and reduces cracking. Always check your tile manufacturer's recommendation.
Does grout joint width change how much grout is needed by a lot?
Yes — grout quantity scales roughly linearly with joint width. Doubling the joint width roughly doubles the grout needed, so even a small difference matters on a large job.
How much extra grout should I buy for repairs later?
One extra bag is common practice, both for spillage during application and to keep grout from the same production batch on hand, since color can vary slightly between batches bought months or years apart.
Epoxy vs cement-based grout — are coverage rates different?
Yes — epoxy has a different formulation and is typically sold in different package sizes. It's more stain-resistant and doesn't need sealing, but costs more. This calculator's constants are for standard cement-based grout, not epoxy.