How Much Tile Do I Need? Calculator + Overage Guide
Buying too little tile means a frantic reorder — and on natural stone, a reorder can arrive from a different lot with different veining. Buying too much wastes money. The fix is simple math plus the right overage. This guide walks you through it and includes a calculator you can use right now.
The basic formula
Tile coverage is measured in square feet. To find the area of any rectangular surface:
So a floor that’s 10 ft by 12 ft is 120 square feet. Measuring a wall? Same math — height × width. Always measure in feet (convert inches by dividing by 12, e.g. 6 in = 0.5 ft), and round each measurement up slightly to be safe.
Estimates only. Always confirm coverage and box size on the product page before ordering.
The overage rule — always order extra
Never order the exact square footage of your space. You need extra material for cuts around edges, breakage, mistakes, and a few spare tiles for future repairs. How much extra depends on your layout:
- Straight / grid layout: add 10%. The standard for most floors and walls.
- Diagonal layout: add 15%. Angled cuts create more waste at the edges.
- Herringbone, chevron & patterns: add 20% or more. Lots of angled cuts and a busier layout mean more offcuts.
- Lots of cuts (small bathrooms, niches, many corners): lean higher. More edges = more waste.
Three things people forget
Measure each area separately
Break an L-shaped room into rectangles, calculate each, then add them up. Measure walls and floors as separate totals — they often use different tile.
Check how the tile is sold
Some products sell by the square foot, others by the sheet (mosaics) or the piece (moldings, large-format). The product page lists coverage per unit — match your total to that so you order the right count. Many of our stone tiles also carry a minimum order quantity.
Buy it all in one lot
Natural stone is quarried in batches, and color can shift between lots. Order your full quantity plus overage in a single purchase so everything matches.
Frequently asked questions
How do I calculate how much tile I need?
Multiply the length by the width of your area in feet to get square footage, then add 10% for a straight layout (15% diagonal, 20%+ for patterns). Divide the total by the coverage per box to find how many boxes to order.
How much extra tile should I buy?
At least 10% over your measured area for straight layouts, 15% for diagonal, and 20% or more for herringbone and patterned installations. The extra covers cuts, breakage, and future repairs.
How many square feet are in a box of tile?
It varies by product. Coverage per box is listed on each product page. Divide your total square footage (including overage) by that number and round up to get the number of boxes.
Should I keep extra tiles after installation?
Yes. Keep a few spare tiles from the same lot. If a tile is ever damaged, a matching replacement from a future lot may differ in tone and veining.
Do mosaics and large-format tiles calculate differently?
The square-footage math is the same, but mosaics are usually sold by the sheet and large-format or moldings by the piece. Check the coverage per unit on the product page and match your total to it.
Know your number? Order a free sample first to confirm the current lot, then buy your full quantity in one go.
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