What Is a Laser Distance Meter? Types and Selection Criteria
A laser distance meter (laser measure) is a handheld measuring tool that measures the distance between the device and a target from the reflection of the laser beam it sends.
A laser distance meter (laser measure) is a handheld measuring tool that measures the distance between the device and a target from the reflection of the laser beam it sends. It is used in surveys to take room and run lengths alone, work out cable and trunking quantities, and calculate area and volume. Laser rangefinders with a viewfinder give the distance of far targets in open ground and on the golf course.
Types of laser distance meter
| Type | How it works | Where it is used |
|---|---|---|
| Laser measure | The laser dot is placed on a wall, ceiling or floor; measures at millimetre level | Indoor dimensions, surveys, quantity take-off |
| Laser measure with tape | A laser meter and a tape measure in one body | Short dimensions, edges and corners, and long dimensions with one tool |
| Mini laser measure | Pocket-size body, built-in rechargeable battery | Frequent short measurements, service and surveys |
| Laser rangefinder | Aimed at the target through a viewfinder; measures at metre level | Open ground, fields, golf |
Selection criteria
- Measuring range: The rated range applies to suitable reflection conditions. Bright daylight and dark or shiny surfaces shorten it; use a target plate at long range. For open-ground distances of hundreds of metres, choose a rangefinder.
- Accuracy: For laser measures, accuracy is given as a distance-dependent formula. The Unit LM A series in the catalogue states ±(2 mm + 5×10⁻⁵·D), i.e. about ±2.5 mm at 10 m and about ±7 mm at 100 m. Rangefinders are accurate to the metre level and are not suitable for building measurement.
- Calculation functions: Area, volume and Pythagorean (indirect) measurement let you calculate heights and lengths you cannot reach directly.
- Measuring reference: Most laser measures measure from the rear edge and can be switched to the front edge or the tripod thread. Check the selected reference on the display.
- Power supply: The models in the catalogue run on AAA batteries (2 × 1.5 V LR03) or a built-in Li-ion battery. The LM40Mi and LM60Mi charge via Type-C.
- Laser safety: The LM A series laser measures use a 630–670 nm, below 1 mW, Class 2 laser; for other models the class according to IEC 60825-1 is given on the device label. Do not stare into the beam.
Common mistakes
- Measuring to glass, mirrors or shiny surfaces: The beam is reflected or passes through and the reading is wrong. Use a matt target or a target plate.
- Not checking the measuring reference: If the front edge is selected instead of the rear edge, the reading is short by the length of the device.
- Missing the right angle in Pythagorean measurement: In indirect measurement one reading must be taken perpendicular to the surface; if the angle slips, the result deviates.
- Trying to measure long distances in sunlight: The dot is invisible and the reflection may be lost. Use a target plate or measure in the shade.
- Taking quantities with a rangefinder: Metre-level accuracy is not enough for cable and trunking quantities; use a laser measure indoors.
Laser distance meters in the catalogue
The Laser Distance Meters category on Welibaba has 12 active products; all are Unit:
- Laser measures: LM50A, LM70A, LM100A and LM120A (50, 70, 100 and 120 m range in their names).
- Laser measures with tape: LM40T and LM60T.
- Mini laser measures: LM40Mi (40 m) and LM60Mi (60 m), Type-C rechargeable.
- Laser rangefinders: LM600G, LM1000G, LM1200G (3–1200 m, 6x magnification, flagpole lock, for golf) and LM1500G.
6 of the 12 products are priced on request: the LM40Mi, LM60Mi and the four rangefinders. For a fitting reference line, see the Laser Alignment Devices category.
Frequently asked questions
How accurate is a laser measure?
For the LM A series in the catalogue, accuracy is given as ±(2 mm + 5×10⁻⁵·D). Over room dimensions the error is a few millimetres; at 100 m it rises to about ±7 mm.
What is the difference between a laser measure and a laser rangefinder?
A laser measure places a laser dot on a wall or ceiling and takes indoor measurements at millimetre level. A rangefinder is aimed at the target through a viewfinder; it is for long distances in the open and is accurate to the metre level.
What is Pythagorean measurement used for?
It calculates a height or length that cannot be measured directly from two or three readings. For example, the height of a façade is found from readings to the top and to the perpendicular point, with the device held at the same spot.
Can a laser distance meter be used outdoors?
Yes, but in sunlight the laser dot is invisible and the range is shorter. Use a target plate over long distances; for open-ground measurements of hundreds of metres choose a rangefinder.