Which Laser Level Do You Actually Need?

Everything in this part of the catalogue looks alike: a small yellow-and-black box that projects something red or green. They are six different instruments doing six different jobs, and the model name tells you which — if you read the letters rather than the numbers.

GLM — measuring a distance

The one most people should own first, and the cheapest thing here. Point it at a wall, press the button, read the distance. It replaces a tape for every measurement longer than your arms, does it alone, and does it from where you are standing rather than from where the tape has to reach.

On most of these the first number is the working range in metres: a GLM 40-12 measures from 150 mm out to forty metres. It is a useful way to read the range at a glance rather than a rule to rely on, so take the figure from the product page before you buy. Beyond range, the models differ by what they do with the measurement: area and volume, indirect height by trigonometry when you cannot get a straight line to the top of something, memory of the last readings, a camera for aiming outdoors at long range.

• Estimating and quoting indoors. Thirty to fifty metres is more than enough. The cheapest model in the range does this well.
• Working outdoors or across a plot. Go for range and a camera, because past about fifty metres you cannot see where the dot landed.
• Measuring heights you cannot reach. You want the indirect measurement modes, not more range.

GLL — drawing a line

A line laser projects a straight horizontal or vertical line onto the work, and levels itself. It is what you use to run a row of tiles, hang a line of cabinets, set a false ceiling, or get a run of switch boxes at one height.

How many lines, and how far round

The basic models give one horizontal and one vertical line across the wall in front of you. The larger ones give lines that go the whole way round the room: the GLL 3-80 projects three 360-degree lines, so a single setup references all four walls, the floor and the ceiling at once. On a fit-out that is the difference between setting up once and setting up in every corner.

Red or green

Green is the more visible beam — Bosch rate their green points as up to four times more visible than red. In a dim room either works. In a half-built space with daylight coming in, red disappears and green does not. Green costs more and is worth it if you work in daylight; it is wasted money if you are always indoors with the lights off.

For outdoor work neither beam is enough on its own — past a few metres in sunlight you stop seeing the line at all, and you need a laser receiver that detects the beam and beeps. That is a separate purchase, and it is the thing people forget when they buy a line laser for a site rather than a flat.

GPL — dropping a point

A point laser puts dots rather than lines: typically up, down and ahead, so you can transfer a mark on the floor to exactly the same place on the ceiling. That is the drywall and false-ceiling job — setting hanger positions, dropping a column line through floors, plumbing a partition.

If your work is positions, a point laser is smaller, tougher and cheaper than the line laser you would otherwise buy. If your work is alignments, it is the wrong instrument.

GRL, GOL and GIM — the whole-site instruments

A rotation laser spins a beam through a full circle to lay a level plane across a large area — a slab, a car park, a drainage fall. With a receiver on a staff it works at ranges where no line laser is visible, and one person can set levels across a site alone.

An optical level is the same job done with no electronics: a telescope, a tripod and a staff, read by eye. It has no battery to go flat and nothing to lose calibration electronically, which is why they remain standard on civil sites.

A digital inclinometer is a long spirit level that reads the angle as a number. It is for setting a specific fall — a drain, a ramp, a solar frame — rather than for level or plumb, where a bubble is faster.

What people get wrong

• Buying a line laser for outdoor work without a receiver. The line is invisible in sunlight. The receiver is not optional, it is part of the tool.
• Paying for green when all the work is indoors. With the lights down, red is perfectly visible and costs less.
• Buying a line laser to transfer points. A point laser is smaller, cheaper and more accurate at the one thing you need.
• Forgetting the tripod. Most of these are useless on the floor. Check whether the model has a tripod thread and whether a tripod is in the box.
• Treating accuracy figures as a ranking. A tenth of a millimetre per metre and three tenths are both far finer than tile work needs. Buy for range, visibility and the number of lines.

See the measuring range or describe the job — indoors or out, how far, what you are setting — and we will say which instrument it needs. Prices include GST, with a proper tax invoice on every order.