Grit is the number that describes how coarse or fine an abrasive is. Lower numbers are coarse and remove material fast, while higher numbers are fine and refine the surface. In concrete polishing, grits run from coarse grinding steps under 100 up to about 3,000 for the highest shine. Each step removes the scratches left by the step before.
What Grit Means for Your Polished Concrete Floor
Grit on concrete works like sandpaper on wood. You start coarse to shape the surface, then go finer and finer until it’s smooth enough to shine. The diamond tooling on a floor grinder is labeled the same way.
The last grit the crew uses sets how shiny your floor ends up. A satin finish stops at about 400 grit, a polished look goes to 800 grit or higher, and the glossiest floors go up to 3,000 grit. Those finishes line up with the four sheen levels. Each extra step adds labor, so a higher grit usually means a higher quote.
Skipping steps causes trouble. Each finer grit has to remove the scratch pattern from the grit before it. Jump too far and those scratches stay in the floor and show once the shine comes up.
Grit FAQ
What grit is polished concrete?
There’s no single number. A satin floor stops around 400 grit, a typical polished floor goes to 800 or beyond, and a highly polished floor can go up to 3,000. Your contractor picks the stopping point based on the sheen you want.
What is the difference between 400 grit and 800 grit polished concrete?
A 400-grit floor has a soft, low sheen, a bit like an eggshell paint finish. An 800-grit floor reflects light much more clearly and reads as truly polished. The 800-grit floor takes more passes, so it usually costs more.