Patio Tile Calculator

Why Simple Calculators Fail Outdoors

Most tile calculators ask for two numbers: length and width. They multiply, add 10 percent, and give you a tile count. That works if your patio is a perfect rectangle with nothing in the way. Most patios aren't. They wrap around corners, step down to garden level, dodge drain covers, accommodate planting beds, and follow the irregular boundary of the house.

An L-shaped patio that's 6 metres (19 feet 8") by 4 metres (13 feet 1") on one side and 3 metres (9 feet 10") by 2 metres (6 feet 7") on the extension can't be accurately calculated as a single rectangle. If you treat it as the bounding rectangle (6 by 4 = 24 square metres / 258 sq ft), you're overbuying significantly because the corner isn't actually there. If you try to manually calculate it as two rectangles and add them together, you might get the area right but you'll miss the extra cuts along the internal corner where tiles meet the junction. Those junction cuts produce waste that a simple area sum doesn't capture.

Outdoor tiles also use wider joints than indoor tiles, typically 3-5mm (1/8" - 3/16") compared to 1-2mm (1/16" - 3/32") inside. On a 600mm (23 5/8") patio slab, a 5mm (3/16") joint versus a 2mm (1/16") joint changes how many tiles fit across a 4-metre (13 feet 1") run. Over the whole patio, that difference can shift your tile count by a full row. Then there are the obstacles: drain covers, manhole access points, support posts, and planting features that all create cuts and waste that a length-times-width calculation simply cannot account for.

How Herron Calculates Patio Tiles Properly

Herron lets you draw the actual shape of your patio. Not a rectangle. Not two rectangles stitched together. The real boundary, with every angle, jog, and offset. You draw it as a polygon on screen, clicking point by point around the perimeter. If your patio has a curved garden edge, you approximate it with short straight segments, which gives a far more accurate area than rounding to the nearest rectangle.

Then you add obstacles. Drag in a rectangle for the drain cover. Draw a polygon around the support post. Each obstacle gets excluded from the tile layout, and the tiles that would overlap it get clipped to shape. The result is a layout that shows you exactly which tiles need cutting around the drain, how much of each tile is wasted, and what the total material count actually is.

The engine places every tile into your patio shape, clips them to the boundary, and calculates waste from the actual geometry. It doesn't estimate. It counts. Full tiles, cut tiles, and waste pieces are all tracked individually. You get a tile count that reflects your specific patio, not a generic approximation that might be off by a box or three.

What You Get

A tile layout that matches your patio shape. See every tile placed into your actual patio boundary. Full tiles in the middle, cut tiles along every edge, shaped cuts around obstacles. The visual layout shows you exactly where each tile goes, including which ones need angled cuts for non-90-degree boundaries.

Accurate tile counts for irregular shapes. Herron counts the tiles your layout actually uses, not the tiles a rectangle would need. For an L-shaped patio, that difference can be 15-20 percent. For a patio with multiple obstacles, even more. The count includes full tiles, cut tiles, and the total number of tiles you need to purchase (since each cut tile still comes from a full tile).

Real waste percentages. Outdoor tiling typically produces higher waste than indoor because patio shapes are less regular and tile sizes are larger (cutting a 600mm patio slab produces bigger offcuts than cutting a 300mm wall tile). Herron calculates waste from every cut in your specific layout. You might find that rotating the tile grid 90 degrees produces noticeably less waste. Try it on screen in seconds instead of discovering it mid-lay.

A cut list for every tile. Numbered, dimensioned, row by row. For patio work where you're often cutting with a wet saw outdoors, having the full list of cuts prepared in advance means you can batch your cutting. Cut all the edge pieces in one session rather than running back to the saw every few tiles. That alone saves significant time on a large patio.

Material cost estimate. Enter the price per tile or per box and Herron calculates your total material cost based on the actual layout. Compare tile sizes: would 600mm by 600mm slabs or 450mm by 450mm tiles produce less waste for your shape? The cost estimate tells you immediately.

Frequently Asked Questions