Estimate how many 25-lb bags of grout you need for a tile project. Coverage scales with tile size, joint width, and joint depth.
Usage Tip
Buy a little extra so the whole job comes from the same dye lot; grout color can vary between bags.
bags = round up( area ÷ coverage per bag )
Coverage assumes a 25-lb bag covers 200 square feet of 12-inch tile with 1/8-inch wide, 1/4-inch deep joints.
How Much Grout Do I Need?
Grout fills the joints, so the math is about total joint volume, not floor area alone. Smaller tiles mean more joints per square foot and more grout; wider and deeper joints mean more grout per joint. Enter the tile size, joint width, and joint depth and the calculator works out the volume, the bags, and the cost.
Grout Coverage by Tile Size
Approximate coverage from a 25 lb bag of sanded grout at a 1/8 in joint, 1/4 in deep – notice how it climbs with tile size:
| Tile size | Coverage per 25 lb bag |
|---|---|
| Mosaic 2 x 2 in | about 50 sq ft |
| 4 x 4 in | about 100 sq ft |
| Subway 3 x 6 in | about 130 sq ft |
| 12 x 12 in | about 290 sq ft |
| 12 x 24 in | about 390 sq ft |
| 24 x 24 in | about 580 sq ft |
Double the joint width or depth and the grout roughly doubles too. Always check the bag, which lists coverage for common tile and joint combinations.
Sanded vs Unsanded Grout
| Type | Use it when |
|---|---|
| Sanded | Joints 1/8 in and wider – floors and most walls; sand resists shrinking and cracking |
| Unsanded | Joints under 1/8 in, and polished/soft tile (marble, glass) that sand would scratch |
| Epoxy | Wet, stain-prone areas – waterproof and stain-proof, but harder to work and pricier |
| Urethane | Premixed, flexible, ready to use – convenient for small jobs |
The rule of thumb: sand for wide joints, no sand for narrow. Sanded grout in a sub-1/8 in joint will not pack properly; unsanded in a wide joint will crack as it shrinks.
Grout Joint Size Guide
| Tile | Typical joint |
|---|---|
| Mosaic / glass | 1/16 – 1/8 in (unsanded) |
| Subway / wall | 1/16 – 1/8 in |
| Standard floor (12 in) | 1/8 – 1/4 in (sanded) |
| Rustic / large-format | 3/16 – 1/2 in (sanded) |
Shower & Floor Installation
Showers and wet areas: use a waterproof setup and strongly consider epoxy grout for the floor and corners; seal cement grout well and keep an expansion joint (silicone, not grout) at changes of plane and corners. Floors: use sanded grout for the typical 1/8-1/4 in joints, work it in fully on the diagonal with a float, and clean the haze before it dries. Mix only what you can use before it sets.
Grout Sealing & Curing
| Stage | Typical time |
|---|---|
| Light foot traffic | 24 hours |
| Full cure | 48-72 hours |
| Ready to seal | after full cure |
| Shower use | after cure + seal (check label) |
Grout Maintenance Tips
- Seal cement grout on installation and re-seal every 1-2 years in wet areas.
- Clean with pH-neutral cleaner; avoid acids and harsh bleach that erode grout.
- Wipe shower walls to reduce soap scum and mildew.
- Repair cracks early; regrout small areas before water gets behind the tile.
- Keep a little leftover grout (note the color/lot) for repairs.
Frequently Asked Questions
How much grout do I need?
It depends on tile size, joint width, and depth – not just area. Enter all three above and the calculator returns bags and cost.
Sanded or unsanded grout?
Sanded for joints 1/8 in and wider; unsanded for narrower joints and for scratch-prone polished tile.
Why do small tiles need so much more grout?
More tiles per square foot means far more total joint length to fill, so mosaics use several times the grout of large-format tile.
Do I need to seal grout?
Seal cement grout after it cures (48-72 hours). Epoxy and urethane do not need sealing.
How long before I can use the shower?
Generally after full cure (48-72 hours) plus sealing – follow the grout label.
Should I use epoxy grout in a shower?
It is waterproof and stain-proof and excellent for wet areas, though harder to apply and more expensive than cement grout.
Related Calculators
Note: grout coverage is an approximation and varies by product, tile shape, joint profile, mixing, and waste – always check the bag coverage chart for your tile and joint, and buy extra from one lot. General DIY guidance, not a professional specification.