The calculator converts your width and height from inches to square feet, applies a waste factor for cuts and breakage, then multiplies by the tiles-per-square-foot rate for your chosen tile size. Grout and mortar are estimated at ~1.5 lbs/sq ft and ~4 lbs/sq ft respectively based on standard 1/4-inch trowel and joint-width applications.
10% is typical for straight layouts (subway tile in running bond). Increase to 15-20% for diagonal patterns, mosaics, or around outlets and windows. Add more if you're new to tiling — practice cuts and breakage add up.
Always buy at least the calculated amount, plus 10-15% extra. Dye lots vary between boxes, and broken tiles or regrets happen. Leftover tile is useful for repairs later.
Yes, but note that floor installations typically use more mortar (thicker beds) and higher-quality grout. Use this as a baseline and add 20-30% extra material for floors.
Subway tile typically uses 1/16" to 1/4" joints. The calculator assumes average spacing; wider joints use more grout, narrower joints use less. Verify your chosen width and adjust material purchases accordingly.
Measure around them or subtract their area from your total. Outlets require tile cuts; windows need edge trim. Account for extra waste on these sections and buy extra tile for practice cuts.
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.