Measure the square footage of the room in feet with a tape measure. Multiply the length by the width of the room with a calculator to determine the total square footage you need to cover with the sealer.
Examine the bucket of the sealer you wish to use. Each container tells you how much square footage each bucket is intended for. This lets you know how many buckets of sealer you need for your floor. This varies by brand.
Multiply the number of buckets you need for one coat by the number of sealer coats you want on the floor. You'll usually want at least two coats of sealer on the floor for best results.