Tile Calculator
Work out how many tiles you actually need for a floor, wall or backsplash — with grout joints, pattern waste, box counts, grout, adhesive and total cost all worked out. Add as many areas as your project has and buy whole boxes with confidence.
- ✓ Grout joints included
- ✓ Pattern-based waste
- ✓ Boxes, not decimals
- ✓ Grout & thin-set estimate
- ✓ Imperial & metric
Your project
Tile size & layout
Boxes & price
Grout & adhesive
Why this tile calculator gives a number you can actually order
Most tile calculators divide your floor area by the tile area and stop. That quietly under-counts every job, because it ignores the grout joint, the pattern and the fact that tile is sold in sealed boxes.
Grout joints counted
Each tile really occupies its own size plus one joint. A 1/8 in joint on 12 x 12 tile changes coverage by about 2%, and on small mosaics or metro tile the difference is far bigger.
Whole boxes, not decimals
You cannot buy 107.7 tiles. Enter tiles per box and you get boxes to order, the tile count inside them and how many spares you will be left holding.
Waste set by pattern
Straight grid, brick offset, diagonal and herringbone all cut differently. Pick the layout and the allowance moves with it, or override the percentage yourself.
Multiple areas at once
Floor, shower walls and a backsplash in one estimate, each with its own deduction for cabinets, tubs, niches or a doorway.
Grout and thin-set too
Grout is worked out from real joint volume using your tile thickness, and adhesive from your trowel notch, so the whole material list is priced in one place.
Imperial and metric
Feet with inch tiles, or metres with millimetre tiles. Every field, preset and result converts when you flip the switch.
How to use the tile calculator
Five inputs and you have an order list.
- Measure each area
For a floor, use length and width. For a wall or backsplash, use width and height. Split L-shaped rooms into rectangles and add each as its own area.
- Deduct what you are not tiling
Enter the area of kitchen islands, a bath tub footprint, a shower tray or a doorway in the deduction field so they never enter the tile count.
- Enter tile size and joint
Pick a preset or type a custom size, then set your grout joint. The calculator adds one joint to each tile before dividing.
- Choose your layout
Straight grid needs about 10% extra, diagonal about 15% and herringbone about 20%. Push it higher for a room full of angles and pipe cuts.
- Read the shopping list
You get boxes to order, spare tiles, grout and thin-set bags if you want them, and a running material cost.
How many tiles per 100 square feet?
Based on a 1/8 in grout joint and a 10% waste allowance for a straight grid layout.
| Tile size | Coverage per tile | Tiles for 100 sq ft | With 10% waste |
|---|---|---|---|
| 3 x 6 in metro | 0.133 sq ft | 753 | 828 |
| 6 x 6 in | 0.261 sq ft | 384 | 423 |
| 12 x 12 in | 1.021 sq ft | 98 | 108 |
| 12 x 24 in | 2.031 sq ft | 50 | 55 |
| 18 x 18 in | 2.281 sq ft | 44 | 49 |
| 24 x 24 in | 4.042 sq ft | 25 | 28 |
And the metric equivalent, per 10 m² with a 3 mm joint and the same 10% allowance.
| Tile size | Coverage per tile | Tiles for 10 m² | With 10% waste |
|---|---|---|---|
| 100 x 300 mm | 0.0312 m² | 321 | 353 |
| 300 x 300 mm | 0.0918 m² | 109 | 120 |
| 300 x 600 mm | 0.1827 m² | 55 | 61 |
| 450 x 450 mm | 0.2052 m² | 49 | 54 |
| 600 x 600 mm | 0.3636 m² | 28 | 31 |
| 600 x 1200 mm | 0.7254 m² | 14 | 16 |
What getting the count right saves you
- ✓No dye-lot mismatch. Tile is made in batches. A top-up box bought three weeks later can be a visibly different shade, and it will land in the middle of your floor.
- ✓No stalled job. Running short mid-install means pulled-up spacers, part-set adhesive and a wasted weekend waiting on stock.
- ✓Honest budgeting. Boxes, grout and adhesive are priced together so the real number is not a surprise at the counter.
- ✓Spares for later. A few tiles set aside means a cracked tile in year three is a repair, not a re-floor.
- ✓Smarter pattern choice. Seeing herringbone cost 20% more tile up front helps you decide before you commit.
- ✓Less returned stock. Opened boxes are often non-returnable, so over-ordering by two boxes is money gone.
Tile calculator FAQs
The questions people ask before they order.
How many 12x12 tiles do I need for 100 square feet?
With a 1/8 in grout joint each 12 x 12 tile covers 1.021 sq ft, so 100 sq ft takes 98 tiles. Add the standard 10% waste allowance for a straight grid and you need 108 tiles. If your boxes hold 12 tiles that is 9 boxes, giving you 108 tiles with none to spare, so most people take a tenth box for offcuts and future repairs.
How much extra tile should I buy for waste?
Ten percent is the standard for a straight grid in a simple rectangular room. Go to 12% for a brick or offset bond, 15% for diagonal, and 20% for herringbone because every run ends in a cut. Add another 5% on top for rooms with lots of angles, pipe penetrations, alcoves or if you are working with large-format tile that cracks when scored badly.
Do grout lines change how many tiles I need?
Yes, and most calculators ignore it. Each tile occupies its own size plus one grout joint, so a 12 x 12 tile with a 1/8 in joint really takes up 12.125 x 12.125 in. That is about 2% fewer tiles on a large-format floor, but on 3 x 6 in metro tile with a 1/8 in joint it is closer to 6%, which is several boxes on a big wall.
How do I calculate tiles for a herringbone or diagonal pattern?
The tile count is the same, only the waste changes, because both patterns produce a cut at the end of every run and at every wall. Use 15% for a 45-degree diagonal and 20% for herringbone. Select the pattern in the calculator and the allowance is applied for you, or type your own percentage if your tiler has quoted a figure.
How many tiles come in a box?
It varies by size and manufacturer, and boxes are usually sold by coverage rather than count. A box of 12 x 12 in tile commonly holds 12 to 16 tiles for roughly 15 sq ft, a box of 12 x 24 in holds 6 to 8, and metro tile can run 80 or more per box. The figure is printed on the end of the box, so enter that number rather than assuming.
How much grout and thin-set do I need?
Grout depends on joint width, tile size and tile thickness, because you are filling a volume rather than covering an area. Small tiles with wide joints use far more than large-format tile with a 1/16 in joint. Thin-set depends on your trowel: a 50 lb bag covers roughly 95 sq ft with a 1/4 x 1/4 in notch, about 75 sq ft with 1/4 x 3/8 in and only 50 sq ft with a 1/2 in notch. Turn on the grout and adhesive option to get both.
How do I calculate tile for a wall or backsplash?
Use the wall width as the length and the wall height as the width, then put the area of any window, mirror, cooker hood or cabinet run in the deduction field. Standard kitchen backsplashes are 18 in tall between counter and upper cabinets, so a 12 ft run is 18 sq ft before deductions. Add each wall as a separate area so the totals stay checkable.
Should I round up to whole boxes?
Always. Tile is sold in sealed boxes and part boxes are rarely available, so the calculator rounds up for you and shows how many spare tiles that leaves. Keep the spares from the same batch: they are the only guaranteed colour match if a tile cracks or you cut one short during the install.
Order the right number of boxes first time
Measure your areas, pick your tile and layout, and walk into the showroom with an exact box count, a spares figure and a material budget.
Calculate my tiles →