Grout Sealer Calculator: How Much Sealer Do I Need?
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Sealer quantity depends on what you are sealing. Sealing grout lines only needs a small fraction of what full-surface sealing needs, because grout is usually just 1-12% of a tiled surface. Use the coverage rate printed on your sealer, adjust for porosity and coats, and the calculator estimates the amount.
Sealer coverage calculator
Method and assumptions
The calculator finds the grout share of the surface from the tile module, the same geometry used in the grout calculator. For grout-lines-only application it multiplies the grout surface by 1.6 to account for the applicator wetting the tile edges beside each joint. For full-surface application it uses the whole area. Both are multiplied by coats and porosity, then divided by the label coverage rate.
The result is usually small for grout lines only, which is the point: an 8 oz or 16 oz applicator bottle often covers an entire bathroom floor. Buying a gallon for grout lines is a common waste.
| Tile | Linear ft of joint | What it means for sealing |
|---|---|---|
| 2 x 2 mosaic | about 1,130 | Full-surface method is far faster than bottle application. |
| 3 x 6 subway | about 580 | Bottle is workable on a backsplash; spray-and-wipe on large walls. |
| 12 x 12 | about 200 | Applicator bottle is efficient. |
| 12 x 24 | about 150 | Applicator bottle is efficient. |
| 24 x 48 | about 75 | Very little grout to seal; a small bottle suffices. |
Before you buy: confirm the grout should be sealed at all. Epoxy grout and many urethane and premixed grouts should not be sealed, and some high-performance cement grouts do not need it. See do you need to seal grout and does epoxy grout need sealing.
Frequently asked questions
How many coats of grout sealer do I need?
Most penetrating sealers call for one or two coats, the second applied while the first is still damp or within the window on the label. Run a water drop test after curing to see whether another coat is needed.
Why is the label coverage a range?
Coverage depends on how much the surface absorbs. Dense porcelain and high-performance grout take little sealer; open, unsanded or weathered grout drinks much more.
Does this work for grout colorant?
The linear feet figure does. Colorant coverage is usually stated per linear foot or per bottle for a joint width, so use the linear feet result with the colorant label.
Sources and standards
- Sealer manufacturer technical data sheets (coverage ranges and application windows).
- ANSI A108.10, Installation of Grout in Tilework.
Grout Atlas guidance is checked against ANSI A108/A118 and ISO 13007 requirements, the TCNA Handbook and manufacturer technical data sheets. Product formulations change, so confirm details on the current data sheet for the product you buy. Spotted an error? Report a correction.