Bosch GLM 15 Laser Distance Measurer
Bosch Tools Bosch GLM 15 Laser Distance Measurer
The simulated laser beam (by the manufacturer) shows how a person working alone could measure the wall opening at a bay window.
Bosch Tools The simulated laser beam (by the manufacturer) shows how a person working alone could measure the wall opening at a bay window.
The GLM 15 on the left was tested against three more expensive models--shown here to indicate relative size.
David Frane The GLM 15 on the left was tested against three more expensive models--shown here to indicate relative size.

A couple of months back Bosch sent me their new GLM 15 laser distance measurer (LDM). It showed up at the beginning of small remodeling project I was doing and I used it throughout. The tool’s claim to fame is that it’s a small simple device from a recognized brand that sells for less than $50.

Given how enamoured most folks are of electronics I’m surprised more people don’t use LDMs. But then those tools have traditionally had a couple of strikes against them; they are far more expensive than tape measures (most sell for between $120 and $300) and are more complicated to operate. The GLM 15 does away with those objections: It’s a fraction of the cost of most name brand LDMs (though still more expensive than a tape) and is simple to use because it performs only two functions, measuring and remembering dimensions.

A single button below the screen is used to turn the tool on and off and to register and clear measurements. The memory can hold two dimensions, which for basic measurements (room area and the like) is probably enough. The scale reads continuously until you hit the button to register the measurement, so the tool can be used to walk off rough distances.

According to its maker the GLM 15 has a range of 50’, which as LDMs go is not very far. The limited range of this tool could be a problem to tradesmen who work in large commercial buildings. It shouldn’t be a problem in small buildings and probably won’t matter outdoors, where ambient light and cluttered backgrounds can make it difficult to see an LDM’s laser dot from any great distance.

The tool is said to be accurate to within +/- 1/8”. That may be its accuracy at 50’ but over shorter distances I could not detect any difference between it and a tape or the three more three more expensive LDMs I tested it against.

I tested it against a tape by measuring between marks on opposite sides of various openings and the dimensions were always the same. I tested it against a Bosch GLM 50 ($115), Fluke 419D ($250) and a Hilti PD 5 ($200) over distances too long to be easily measured with a tape (approximately 6’) and the dimensions were never off by more than 1/32”. That 1/32” was probably a rounding error; the more expensive models measure to the nearest 1/32”; this one measures to the nearest 1/16”.

At greater distances (approximately 40’) measurements between tools varied by +/- 3/32”. But that was between all tools—not between this and the others. I attribute the variation to how hard it is to keep a laser point on target while pressing the button. For precise measurements over long distances it’s best to put the LDM on a tripod and use the timer function. The GLM 15 does not have a tripod mount or timer function so at longer distances you’ll have to settle for less accuracy. For the kinds of measurements most people make +/- 3/32” over 40’ is probably accurate enough.

The GLM 15 has a rubberized bottom and rubberized strips around the back perimeter. I dropped the tool several times onto wood and concrete (from about 3’) and the worst that ever happened was the battery cover came off and the batteries popped out. The falls did not affect accuracy; I remeasured some things after and they measured the same as before.

This tool has very few features. And that’s by design; it’s how Bosch is able to sell an LDM for so little. With that in mind, here are some things I wish the tool had: memory for more than two dimensions, a backlit screen, and a folding tailpiece for making outside to inside corner measurements. Since the tool is designed to replace tapes for certain functions, what would really be nice is a tape measure style belt clip. But I understand why none of these features are there—they would have pushed the price above $50.

The Bottom Line
The GLM 15 is a good LDM for the person who needs to make simple accurate measurements. It won’t measure the angle of a slope, calculate the height of an office building, or transfer dimensions to your smart phone. But then for what the tool costs it would be foolish to expect it to. It’s a great tool for measuring rooms and doing material takeoffs for drywall, paint, and floor coverings. I’d be comfortable using it to measure openings for replacement windows, cabinets, doors, and window coverings.

GLM 15 Specs
Battery: 2 AAA
Range: 50’
Accuracy: +/- 1/8”
Memory: 2 dimensions
Warranty: 2 years
Country of origin: Malaysia
Web price: $49