How to measure your toilet outlet

A new toilet bowl has to line up with the waste pipe you already have. Two measurements decide it: where the pipe goes, and how far it is from the wall. It takes a tape measure and a minute.

1. Find where the waste pipe goes

Look behind and under the bowl. A pipe going down into the floor is a floor outlet (S-trap). A pipe going back into the wall is a wall outlet (P-trap). More on the difference

2. Floor outlet: measure the distance from the wall

• Measure from the finished wall behind the bowl, the tiled surface, to the centre of the outlet in the floor.
• Bowls are listed for set distances. On this site the most common are 250 mm (20 bowls) and 150 mm (20 bowls).
• If yours falls between sizes, many bowls fit a range with a pan collar or connector. The installer confirms on site.
• Old bowl still fitted? The outlet is hidden under it. Look for the model name on the old bowl or its paperwork and check its listed outlet distance, or send photos and let the installer measure.

3. Wall outlet: measure the height

Measure from the finished floor to the centre of the pipe in the wall. Where a listing gives the outlet height, it is 180 mm or 190 mm on this site.

Then see which bowls fit

General information, not professional advice for your home. Fitting or changing a toilet bowl is sanitary work for a PUB licensed plumber (PUB: plumbing works).