Stone Sealer Coverage Calculator
Enter your area, the product's coverage rate, and the number of coats to see exactly how many units of impregnating sealer to buy.
Sealer you’ll need
Total coverage is your area multiplied by the number of coats. Units always round up, so the leftover figure shows the extra coverage in the last container — handy for touch-ups and future re-sealing.
Buying the right amount of sealer
Sealing is what keeps natural stone from staining. An impregnating sealer soaks into the pores so oil, wine, and water can't, and most stone needs it applied in one or two coats depending on how absorbent it is. The amount you buy comes down to three things: your area, the coats, and the coverage rate printed on the bottle.
Coverage rates vary widely because stone varies widely. A tight, polished slab might get 500 square feet from a bottle; a thirsty honed marble half that. When in doubt, size for the lower end of the label's range so a second run to the store doesn't interrupt the job — and keep the surplus for the re-seal your stone will eventually want.
Frequently Asked Questions
How is sealer coverage calculated?
Multiply the area you're sealing by the number of coats to get total coverage required, then divide by the product's stated coverage rate per bottle or gallon and round up to whole units. Two coats over 200 square feet is 400 square feet of coverage; at 250 square feet per bottle that's two bottles.
How many coats does natural stone need?
It depends on porosity. Dense, polished granite may only need a single coat, while porous stone — marble, travertine, limestone, and honed or leathered finishes — usually takes two. Always follow the sealer's label; some products specify a wait time between coats and a maximum number.
Why does the coverage rate vary so much?
A sealer's coverage depends on how thirsty the stone is. Low-absorption stone lets the sealer spread further, so one bottle covers more; a porous or textured surface drinks it up and covers less. Labels often give a range — use the lower end for porous stone so you don't run out mid-job.
What does the leftover figure mean?
Because you can only buy whole units, the last container usually has coverage to spare. The leftover figure is that surplus in square feet. It's useful to keep — impregnating sealers wear over time, and most stone benefits from re-sealing every one to three years depending on use and the water-drop test.
How do I know if my stone needs sealing?
Do the water-drop test: leave a small puddle of water on a clean, dry area for a few minutes. If the stone darkens where the water sat, it's absorbing and should be sealed. If the water beads and the stone stays light, the existing seal is still working.
Educational estimate — follow the sealer's label for coverage, coats, and dry times. Coverage varies with stone porosity and finish.