How do I cut a straight line in tile?

Score-and-snap for straight cuts, a wet saw for porcelain, and the hole-cutting methods for pipes and sockets.

Difficulty: beginner
Time: 30 min
Read: 4 min
Safety: warning

Short answer

For ceramic wall tile, a manual score-and-snap cutter gives a cleaner straight edge than any power tool and costs very little. Porcelain is much harder and needs a wet saw or a diamond blade. Score once, firmly, in a single pass — going over the line twice is what causes a ragged break.

Tile cutting is one of the few jobs where the cheap hand tool genuinely outperforms the power tool for the common case, and where the technique fits in one sentence: one firm pass, then snap.

Safety

Cut tile edges are genuinely sharp and fragments fly — wear eye protection and gloves. Cutting tile with an angle grinder or wet saw produces silica dust, which is a serious respiratory hazard: use water suppression, work outdoors, and wear a properly fitted FFP3 mask. Never dry-cut porcelain indoors without extraction.

Step by step

Find out what the tile is.Ceramic is softer, usually lighter, and the body under the glaze is a different colour. Porcelain is dense, uniform through its thickness, and will destroy a tool meant for ceramic. Check before buying a blade.
Measure and mark on the glazed face.A chinagraph pencil or a fine marker. Measure the actual gap rather than the nominal one, and remember to allow for the grout joint at both ends.
Use a score-and-snap cutter for straight ceramic cuts.Line the wheel up on the mark, and push it across in one firm continuous pass. Then position the snapping bar and press. Clean, quiet, no dust, and better than a grinder for a straight line.
Score once only.A single pass with steady pressure. Going over the line a second time widens and roughens the scored groove, so the tile breaks unpredictably. This is the mistake that ruins most tiles.
Use a wet saw for porcelain and thick tile.A diamond blade with water cooling. Hire one for a day rather than buying for a single room. Feed slowly and let the blade cut — forcing it chips the glaze.
Cut with the glazed face up on a wet saw.The blade cuts downwards through the glaze, so chipping happens on the underside where it will not show. On a grinder, the opposite applies — score the face first.
Use tile nippers for small irregular shapes.Around a pipe or an awkward corner. Score the outline first, then nibble away small pieces rather than trying to take a large bite. Slow, and the only way to get a curve by hand.
Drill holes with a diamond hole saw.For pipes and sockets. No hammer action, low speed, water to cool it, and start at an angle before bringing it upright so it does not skate.
Cut an L-shape in two operations.A score-and-snap cutter cannot make an internal corner. Cut one leg on the wet saw or grinder and snap the other, or make both cuts with a wet saw.
Ease the cut edge.A rubbing stone or a diamond pad along the cut removes the sharp burr and makes it sit better. Two passes and it is done.
Plan cuts so they land where they show least.Set out from the centre so the cut tiles at each end are equal and neither is a thin sliver. Put cut edges into corners and under fittings rather than in the open.
Buy more tiles than you need.Ten per cent over is standard, more for a patterned tile or a complicated room. Breakages during cutting are expected rather than a failure.

Tips

Practise on a spare tile. Two minutes calibrates the scoring pressure and saves several tiles later.
A tile that snaps unevenly usually scored unevenly. Watch the wheel stay in contact through the whole pass, including at both ends.
For one or two cuts, most tile merchants will cut to size for very little. That is often cheaper than hiring a saw.

Common mistakes

Scoring the tile more than once — The second pass widens and roughens the groove, so the break wanders instead of following it. One firm continuous pass is the technique.
Using a ceramic tile bit or blade on porcelain — Porcelain is far harder and blunts them almost immediately. It needs a diamond blade or bit with water cooling.

If it doesn't work

Tile snaps unevenly away from the line

Cause: Scored more than once, or pressure lost at one end — Fix: Single continuous pass with even pressure right off the far edge.

Glaze chipping along the cut

Cause: Blade too coarse, feeding too fast, or cutting face-down on a wet saw — Fix: Slow the feed, use a finer diamond blade and cut glazed face up.

Hole saw skating across the tile

Cause: Started flat with no purchase — Fix: Start at an angle to cut a crescent, then bring it upright once it has bitten. Water throughout.

Thin sliver of tile at one end of the wall

Cause: Set out from an edge rather than the centre — Fix: Set out from the centre line so the cuts at each end are equal and reasonably wide.

Questions people ask

What is the best way to cut tile straight?

For ceramic wall tile, a manual score-and-snap cutter — one firm continuous pass then snap. It gives a cleaner edge than a grinder, costs very little and makes no dust. Porcelain needs a wet saw.

Why does my tile break in the wrong place?

Almost always because it was scored more than once. A second pass widens the groove so the break wanders. Score once, firmly, in a single continuous pass.