How many tiles to buy? Plan it before the store run
You are standing in the tile aisle. The salesperson asks: "How many square meters?". All you know is that the bathroom is 3 by 4 meters. You need a concrete number of boxes for the cart.
Type the room dimensions, tile size and layout pattern (straight, brick, herringbone, diagonal). The calculator adds the right waste buffer, rounds up to whole boxes, and shows how many spare tiles you will have once the job is done.
The defaults reflect real-world waste: straight = 5%, brick = 8%, herringbone and diagonal = 15%, because those layouts produce a lot of cuts. You can raise the buffer, but the calculator will not let you go below the pattern minimum, so you do not end up four tiles short on the last square meter.
It works the same way for ceramic tiles, porcelain, laminate panels and engineered flooring. Same math everywhere: area divided by effective tile footprint, plus a buffer for waste.
How to use it
- Type the room length and width in meters. Measure wall to wall, ideally in two spots (near the floor and higher up): rooms are often a few centimeters off square and it is safer to use the larger reading.
- Pick a tile size from the preset list: 30×30 cm (small floor), 30×60 cm (wall standard), 60×60 cm (the modern floor default), 80×80 cm, 120×60 cm (large-format slab), or laminate panel 120×20 cm. For anything else click "Custom" and type the sides in millimeters.
- Pick a layout: straight (least waste), brick / running bond (every other row shifted), herringbone (a lot of cuts, the most expensive pattern), diagonal (also a lot of cuts, elegant finish). Below the bar you will see a short hint for each pattern.
- Type the grout width (0 to 10 mm). Standard is 2-3 mm for porcelain and 3-5 mm for large formats. Grout increases the effective tile footprint, the calculator handles that automatically.
- Check the waste buffer (5%, 10% or 15%). The calculator picks a sensible default based on your layout. You can bump it up, but you cannot go below the minimum: herringbone must have 15% or you will run out.
- Type how many tiles come in one box (typically 4-8 for large formats, more for small ones). You will find that number on the product spec sheet at the store.
- Switch on "Doors, niches, pipes" if the room has obstacles that need extra cuts. It adds one extra tile, a small buffer for typical complications.
- The result shows two key numbers: tiles to buy (with buffer) and how many whole boxes that is. Below it, a details card: room area, single tile size, effective tile footprint with grout, and how many tiles you will have left over after the job.
When this is useful
Five typical situations where this calculator saves you money and time:
- Planning a bathroom remodel and pricing it out. You type the dimensions, click your tile format and pattern. You get a concrete box count for your cart, you drive to the store with a finished list, no more guessing "10 boxes is probably enough".
- Checking whether the contractor over-ordered. The installer said "buy 15% extra". You run the numbers, the calculator says 5% is enough for a straight layout, you save $50-100 on the difference in box count.
- Comparing the cost of different layouts. You like herringbone but it needs 15% waste instead of 5%. The calculator shows the actual difference in boxes, a real dollar number, not a vague feeling.
- Laying laminate flooring in the living room. Format 120×20 cm, 0 mm grout, brick pattern. The calculator works for panels exactly like tiles, panels also come in boxes of 6-8 pieces, same math.
- Buying extra tiles mid-project. You ran 3 tiles short under the bathtub, but the manufacturer changed the batch and the new color is slightly off. You come back to the calculator and check: if I had bought 10% instead of 5%, I would have had a spare: lesson learned for next time.