Buying guide for best line lasers
Whether you're marking a line around a room for a chair rail, or laying out tiles for a bathroom, a line laser is indispensable. With a clear, sharp line that extends 30 feet or more, it's much quicker, easier, and potentially more accurate than a traditional spirit level. With variations designed for different tasks, from simple spot devices to those that can project a whole three-dimensional frame, line lasers can be highly job-specific.
So which line laser is best for your workshop? It depends on the tasks you need to perform.
How line lasers work
Laser beams have gone from being some kind of sci-fi super-ray, to an everyday part of our lives. They're capable of great accuracy and – in the case of eye surgery – tremendous delicacy.
But what is a laser beam?
LASER stands for Light Amplification by the Stimulated Emission of Radiation. With consumer items like line lasers, the initial light is produced by nothing more complex than an LED – much like you find in a digital clock. That light is "stimulated" by an electrical current, increasing the intensity. It's then concentrated into a dot or line, and projected by prisms or mirrors.
A laser beam always travels in a straight line, but it's not inherently "level."
To level the line laser, some basic devices use a bubble, like on a traditional level. More advanced models have an internal pendulum and sensors, and are self-leveling. They may also have an audible warning if they're out of level.
"Don't confuse three beams with three modes. The first offers three individual beams, the second may only have one or two beams, with options for how you use them."
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Choosing a line laser
To help you choose the best line laser for your particular task we're going to look at four areas that distinguish these tools:
Type
Modes
Accuracy and range
Additional features
Type of line laser
Although all line lasers generate a beam in the same way, there are a few different types. The main variation is the number of beams projected, but there are others, so let's look at each in detail.
Single line or spot
These are the most basic type of laser level, projecting a single beam until it strikes a spot off in the distance (hence, some people call them spot line lasers).
Initial leveling is often done with a bulb or bubble, as with an ordinary spirit level. They're usually cheap, and if you just need to line things up along a wall – coat hooks, or a picture rail, for example – they're perfectly adequate.
They're often small, so very portable, but low power means they have limited range.
Cross line lasers
These are arguably the most popular type of line laser because they offer excellent flexibility at a reasonable price. There are two kinds: those that emit two laser beams, and those that emit three.
Two beams – one horizontal, the other vertical – will give you a crossing point, at 90°, on your chosen surface. If there's nothing in their way, those lines will continue, giving you one line all the way around the room horizontally, and another up the wall, across the ceiling, and down the other side. In practice, range often restricts the actual coverage.
Three beam laser levels project a second vertical beam, at 90° to the first. This gives you lines on front, back and side walls, thus enabling you to work in three dimensions – or all walls of a space at once.
These line lasers are used for everything from drywall installation, to tiling (walls and floors), laying out electrical conduit and lighting, or fitting suspended ceilings.
Rotary line lasers
Cross line lasers are particularly good in household applications. However, for really large areas you need more range, and that's what you get from a rotary laser.
As the name suggests, these lasers don't have a fixed beam, but instead have one that's constantly spinning through 360°. It does this fast enough that the spot it projects appears to be a continuous flat line. Many rotary lasers only create one beam, though some also generate a vertical "plumb" line.
While they could be used when installing a chair rail, or to ensure door heights were the same around a room, their price means they're more often used for commercial building projects. They can be very large, and are used for tasks such as building warehousing and creating parking lots, where their range can be used to best advantage.
Line laser modes
Modes can be confusing, because they often sound the same as the number of laser beams emitted. They are not.
For example, you might see a laser level with three modes: horizontal, vertical, and plumb. Sounds like three beams, right? Wrong. In this case it's a single line laser, but it can project in different modes at the switch of a button. It’s easier to use than one you need to move around to achieve the result, but it’s not a three beam laser.
Another example of a model with three laser modes gives them as level, plumb, and cross. Three beams? Four? Nope. This is actually the description of a two-beam line laser. It's actually a very good, low-cost device, but the description is confusing.
Did you know?
You might think that light beam leveling would have been invented by a builder or engineer, but in fact, it was patented in 1996 by Steven J. Orosz Jr., who designed it for use in cardiac monitoring.
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Accuracy and range
Accuracy
In general, the more you pay, the more accurate the line laser you get.
Entry level models will usually be accurate to around 1/4" over 30 feet. That's pretty good. If you hung a half dozen paintings five feet apart over that distance, we doubt anyone would notice a 1/4" variation.
But if you were laying tile on a floor or wall, that's not really good enough. The standard for mid-range line lasers is 1/8" over 30 feet, and for the majority of people that's as precise as they'll ever need.
That's not to say it can't be improved. During our research we found a number of models that offer greater accuracy, the best of which was 1/16" over 100 feet. That kind of high precision is only found in rotary lasers, and comes with a high price, too!
Range
When we're talking about range, we don't just mean the distance that the beam is visible to the human eye. Although we may not be able to see it, devices called laser receivers can amplify the range considerably – though not all line lasers are compatible.
Cheap lasers are often only powered by standard AA batteries, so beyond twenty or thirty feet the line will disappear – particularly in a bright room. Outdoors, they become virtually useless.
Mid-range lasers extend to between 60 and 100 feet, depending on model, but those that have a pulse mode will work with laser receivers. With a laser receiver, they can go out to 250 feet or more.
Further than that, you're back in the realm of rotary lasers. The maximum we found for one of those was 2,600 feet. That's half a mile!
Bright light has a detrimental effect on how well you can see a laser, and laser color has an impact. Line lasers come with either a red or green beam. Green lasers are considered easier to see, especially in brighter light. Unfortunately, the diodes are more expensive, and they demand more power for an equivalent range. Hence, red lasers remain common.
Viewing can be enhanced by the use of special laser enhancement glasses and, as they're inexpensive, it's worth considering.
For your safety
Never shine a laser of any kind in someone's eyes. It's a tool, not a toy.
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Additional features
If you've ever used a standard spirit level and tried to judge when the bubble was exactly in the middle, you'll appreciate the self-leveling option available on some line lasers. You manually get the device within three or four degrees, it does the rest. It makes setting up a whole lot easier. An override means you can set the level at an angle if you like (when putting in stairs, for example). The mechanism should be lockable, so it doesn't get damaged in transit.
Many laser levels have a tripod attachment point. A tripod is a much more convenient and repeatable method of setting up than resting your tool on steps or boxes. A few laser levels include them in the package, but usually you have to pay extra. If you already own a tripod, threads are often common, but check for compatibility anyway.
Clamps or magnets on bases are another good idea, allowing you to fix line lasers to ceiling rails, shelves, or anywhere convenient. As with a tripod, having a sturdy anchor-point ensures accuracy.
Batteries vary and can make a huge difference. It's common for budget models to have rechargeable AA or AAA versions; some use button cells. Larger lasers might use the same kind of 12 volt battery pack as a drill driver or other cordless tool. More power almost invariably means greater range. If you already have power tools from a particular manufacturer, battery compatibility will save you money on buying a spare. Do check, though. Sometimes they look similar, but are not the same.
A case is always a good idea. Line lasers are usually pretty robust, but it's nice to have extra protection.
Did you know?
Many line lasers have a tripod mount, but most of the time the tripod itself is not included.
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Line laser prices
If you just want to line up a few pictures, or make sure a shelf is level, a simple, single-line laser will do the job for under $20. Set up is manual, using a built-in, bubble line in a traditional level, then a beam is fired from one or both sides. Simple and effective, every toolbox should have one.
A cheap, two-line cross laser comes in at around $50 and is good enough for small tiling jobs, aligning cupboards, and similar projects. If you're a professional, you'll probably want greater accuracy and range. The best line lasers of this kind will cost you around $300. If you need the all-around alignment that a three-beam laser line offers, you'll need to add another $100.
Beyond that, you're into the realm of high-end rotary lasers, and you can pay anything from $400 to several thousand dollars.
Tips
A line laser is an indispensable tool that projects a precise guide onto your work surface. Where practical, it's still a good idea to physically mark the surface in case the laser gets knocked. They're easy to align the first time, but can be difficult to re-align to the same position. The longer the distance involved, the more exaggerated the difference becomes.
If you're doing a lot of work that requires a 90° angle – maybe building a garden deck, or tiling floors and walls – a laser square is cheap and very handy. You might also consider a professional tile laser, designed specifically for the task.
Keep a spare set of batteries handy. You can guarantee the ones in your laser line will go flat at the least convenient moment!
FAQ
Q. Is the laser in a laser level dangerous?
A. The majority of levels use Class 2 or 3 lasers. Class 2 are considered low risk, and only likely to cause harm if looked at under magnification. Class 3 are medium risk and can cause eye damage if viewed directly. There's no danger from the projected line, but you should never look directly at the source of the beam, particularly if you wear prescription glasses.
Brief, accidental exposure is unlikely to do permanent damage, but can cause momentary "flash blindness," the same as you might have experience when having your photo taken. That could be dangerous if you're up a ladder, or operating a power tool.
""Plumb" means vertical, at 90° to the horizontal. A "plumb bob" or "plumb line" was originally a string with a lump of lead on the end. They were also used for judging the clearance between a ship and the sea floor, hence "plumbing the depths.""
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Q. Line laser cases often have IP ratings. What are they?
A. IP stands for ingress protection, a standard developed by the International Electrotechnical Commission. Originally, it defined how well industrial enclosures coped with dust and water. Today, many consumer devices are also included. The initials IP are followed by two digits. The first is a rating for particles, the second is for liquids.
Full specifications are available online but to give you a rough idea: an IP54 case might allow in dust, but not enough to stop it from working. It would survive water splashes – like five minutes under a garden sprinkler. An IP65 case is completely sealed against dust, and would survive a good soaking from a hose – but not total immersion.
Q. If a rotary laser has the greatest range, wouldn't that be the best choice?
A. Rotary lasers are very powerful, and offer the best performance outdoors, but unless you're building a warehouse, or laying tarmac for a corporate parking lot, they're probably overkill. For the vast majority of tradespeople and DIY users, a cross-line laser is more than adequate, and even the best are considerably cheaper than rotary laser levels.
