Free tile grout calculator for bathrooms, kitchens, and floors. Enter tiled area, joint spacing, and waste to estimate grout bags and total pounds to order.
Quick answer: this calculator assumes one 25 lb bag of grout covers 60 sq ft at a 1/8 in joint, and scales coverage down as joints get wider. A 10 × 12 ft floor (120 sq ft) plus 10% waste is 132 sq ft ÷ 60 = 2.2, so buy 3 bags (75 lb).
Grout fills the joints between tiles, so the amount you need depends on how much joint there is and how wide and deep it is. This calculator uses a simple, conservative rule: a 25 lb bag covers 60 sq ft at a 1/8 in joint, and coverage shrinks in proportion as the joint widens (a 1/4 in joint is twice as wide, so a bag covers 30 sq ft).
A 15 × 20 ft living area is tiled with 3/16 in joints and 10% waste:
The tool does not ask for tile size, but tile size changes grout use a lot. Small tiles have far more joint per square foot than large tiles. Joint length per square foot of floor is (tile length + tile width) ÷ (tile length × tile width) × 144, in inches. Multiply by joint width and tile thickness to get the volume of grout per square foot. The 60 sq ft-per-bag baseline is realistic for small-format and mosaic tile; for 12 × 12 in and larger tile it over-orders, so compare the result with the coverage chart printed on your grout bag before buying many extra bags.
The first table shows the coverage this calculator assumes. The second is pure geometry: how much joint each tile size creates at a 1/8 in joint, before any manufacturer yield is applied.
| Joint width | Decimal (in) | Sq ft per 25 lb bag (calculator) | Bags for 100 sq ft + 10% waste |
|---|---|---|---|
| 1/16 in | 0.0625 | 120 | 1 |
| 1/8 in | 0.125 | 60 | 2 |
| 3/16 in | 0.1875 | 40 | 3 |
| 1/4 in | 0.25 | 30 | 4 |
| 3/8 in | 0.375 | 20 | 6 |
| 1/2 in | 0.5 | 15 | 8 |
| Tile size (thickness) | Joint length per sq ft | Grout volume per 100 sq ft |
|---|---|---|
| 1 × 1 in mosaic (1/4 in) | 288 in | 900 cu in |
| 2 × 2 in mosaic (1/4 in) | 144 in | 450 cu in |
| 3 × 6 in subway (5/16 in) | 72 in | 281 cu in |
| 4 × 4 in (5/16 in) | 72 in | 281 cu in |
| 12 × 12 in (3/8 in) | 24 in | 113 cu in |
| 12 × 24 in (3/8 in) | 18 in | 84 cu in |
It depends on tile size and joint width. This calculator uses a conservative 60 sq ft per 25 lb bag at a 1/8 in joint, which suits small tile and mosaics. With 12 × 12 in or larger tile and narrow joints, the manufacturer's chart on the bag will usually show more coverage.
With this calculator's assumptions and 10% waste, 100 sq ft needs 2 bags (50 lb) at a 1/8 in joint, 3 bags at 3/16 in, and 4 bags at 1/4 in. Larger tile with thin joints needs less.
Unsanded grout is typically used for joints 1/8 in wide or less, and sanded grout for wider joints because the sand resists shrinking and cracking. Always follow the joint-width range printed on the product you buy.
Yes. Grout volume rises in direct proportion to joint width, so doubling the joint from 1/8 in to 1/4 in doubles the grout. In this calculator that cuts coverage from 60 to 30 sq ft per bag.
Add about 10% for mixing loss and cleanup. Keeping one unopened bag from the same lot is also useful for future repairs, since a later batch may not match in color.
How we built this calculator: results use the standard volume, area, and coverage formulas shown on this page, with typical U.S. material densities, bag yields, and waste factors that you can override. Written and checked by the YardsCalculator editorial team. Last reviewed: October 2026.
Last updated: May 26, 2026