TL;DR
For a quick tile count in metric with nothing to sign up for, use the Calc Garden tile calculator: type the room size in metres, the tile size in centimetres and the waste percentage you want, and it shows the tiles to buy straight away, entirely in your browser. This is not an "only free one" claim: Omni Calculator and Calculator.net both run free, no-signup tile calculators that also handle grout gaps, boxes and cost, and the Topps Tiles calculator is free too and copes with several areas and obstacles. The real choice is a fast, neutral count versus a fuller estimate that tells you how many boxes to order and what they will cost.
What makes a tile calculator "best"
Every tile calculator runs the same core sum: divide the area you are covering by the area of one tile, add a margin for cuts, round up. Since that arithmetic is shared, the tools separate on what they wrap around it, and that is where the right pick is decided. Three things matter. The first is how much the tool asks of you before it answers: a count from three or four fields is a different experience from a form with units, gaps, box sizes and prices to fill in. The second is whether the estimate is neutral or attached to a shop, because a retailer calculator prices your job against one catalogue. The third is scope: do you just need to know how many tiles, or do you need boxes, cost and obstacles subtracted as well?
Those pull against each other, so there is no single winner. A lean calculator is best when you are standing in the room with a tape measure and want a number you can trust in ten seconds. A fuller estimator is better when you are about to place the order and need to know whether that is nine boxes or ten, and what it comes to. The table below lines up four free options against exactly these points.
The best free tile calculators compared
In the table a Yes means the tool does it cleanly, "Partial" means it does it with caveats, and a No means it does not. All four are free with no account required; the pricing row reflects each product as of 2026.
| Capability | Calc Garden | Omni Calculator | Calculator.net | Topps Tiles |
|---|---|---|---|---|
| Price (as of 2026) | Free, no signup | Free, no signup | Free, no signup | Free, no signup |
| Tile count from area and tile size | Yes | Yes | Yes | Yes |
| Waste percentage you set yourself | Yes | Yes | Partial | Partial |
| Grout gap allowance | No | Yes | Yes | Yes |
| Boxes to order | No | Yes | Yes | Yes |
| Total cost estimate | No | Yes | Yes | Yes |
| Several areas or obstacles subtracted | No | No | No | Yes |
| Updates live as you type | Yes | Yes | No | No |
| Neutral, not tied to one shop's range | Yes | Yes | Yes | No |
| Shareable link to your figures | Yes | No | No | No |
Read it honestly. Omni Calculator is the most complete free tile tool here: it takes a grout gap, a waste factor, tiles per box and a price per box, and hands back the count, the boxes and the total cost, all without an account. Calculator.net covers the same ground with more unit options and a longer explainer on layouts, though you press a button rather than watching the number move. Topps Tiles is the one to use when the room is awkward, because it is the only one of the four that takes up to four separate measurements and lets you subtract a window or a door, but it is a retailer tool and its boxes and prices come from the Topps range. Where Calc Garden wins is the first ten seconds: three or four fields, a metric answer that already includes your waste allowance, and a link you can copy to send the figures to whoever is doing the buying.
How the tile count is worked out
The formula is short enough to check by hand, which is exactly why it is worth seeing. Take the area you are covering, divide by the area of one tile, multiply by one plus your waste percentage, then round up to a whole tile:
tiles = ceiling((area in m2 / tile area in m2) x (1 + waste / 100))
Work through the example the Calc Garden tile calculator lands on by default. A floor 3m long by 2.5m wide is 7.5 square metres. A 30cm by 30cm tile is 0.3m by 0.3m, so it covers 0.09 square metres. Dividing 7.5 by 0.09 gives 83.3 tiles to cover the bare floor. A 10 percent waste allowance takes that to 91.7, and since nobody sells two thirds of a tile it rounds up to 92. Change the tile to 60cm by 60cm and the same floor needs 0.36 square metres per tile, so 7.5 divided by 0.36 is 20.8, and with 10 percent waste you are buying 23 tiles.
The rounding matters more than it looks on small jobs. On the 60cm example, one extra tile is over 4 percent of the order, which is why a calculator that rounds up at the end rather than the middle gives you a tighter number than doing it in your head.
Grout gaps, and why leaving them out is safe
Calc Garden works from the bare tile size and ignores the grout line, which is the one place a fuller tool is more precise. The direction of the error is worth knowing, though, because it is the safe direction. A tile plus its grout line occupies more floor than the tile alone, so allowing for gaps means you need slightly fewer tiles, not more. On the 3m by 2.5m floor with 30cm tiles and a 3mm joint, each tile effectively occupies 30.3cm by 30.3cm, and the count before waste falls from 83.3 to about 81.7, a difference of roughly 2 percent.
Two percent is comfortably inside a 10 percent waste allowance, so ignoring the gap leaves you with a slightly larger margin rather than a shortfall. That flips only on very wide joints or very small tiles, where the grout is a real fraction of the surface. If you are laying mosaic or working to a 10mm joint, use a calculator that takes the gap explicitly.
How much waste to allow
The tile count is the easy part. Choosing the waste percentage is where an order actually goes wrong, and it is the number most people leave at the default without thinking. Ten percent is the right starting point for a straight grid layout in a simple rectangular room, and it matches what retailers assume. A diagonal or brick bond layout wants 15 percent, because every angled cut throws away more of the offcut. A room with alcoves, pipe boxing, a doorway threshold or a lot of short edges wants 15 to 20 percent, since the count of cuts, not the floor area, drives the waste.
Large format tiles justify a higher percentage on the same logic in reverse: fewer cuts, but each mistake costs a much bigger piece. And whatever number you land on, order the whole lot at once. Tile colour and size drift between production batches, so a top-up order weeks later can arrive visibly different from the floor it is meant to match. Keeping three or four spare tiles after the job is finished is cheaper than rematching a batch when one cracks.
When to pick each one
Reach for Omni Calculator or Calculator.net when you are at the ordering stage and need boxes and a total cost, or when the grout joint is wide enough to matter. Reach for the Topps Tiles calculator when the room is not a plain rectangle and you want obstacles subtracted properly, accepting that the prices it quotes are theirs.
Reach for the Calc Garden tile calculator when you want a fast, neutral count with your own waste allowance already baked into the number and no signup in the way. From there, two related tools cover the rest of the room: the paint calculator works out litres for the walls above the tiling, and the gravel calculator handles volumes and bulk bags if the job runs outside. For the wider set of explainers, the guides index collects the rest, including a look at the free paint calculators so the whole room can be estimated in one sitting.