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Should I buy a laser distance meter, or can my phone do the job?

A laser measures a single dimension far more accurately than a phone. A phone measures an entire room at once. The two don't solve the same problem — and most people benefit from both.

The two things don't measure the same thing

A laser distance meter measures the distance from the back of the device to a surface it's pointed at. One number at a time, very accurately. An iPhone with LiDAR measures thousands of points a second and builds a model of the whole room as you walk — many numbers at once, each one a little less certain.

So the question isn't "which is best", but "what are the measurements for". If you're ordering a worktop to size, use the laser. If you're getting a quote for flooring across the whole home, use the phone.

What the laser distance meter is good at

• Accuracy on a single dimension. Manufacturers typically quote ±1.5 to ±3 mm on ordinary models — under good conditions, against a solid surface.
• Long distances. Ordinary models reach 20-50 metres, professional ones further. It measures across a garden or down a long corridor, where a tape measure sags.
• Places you can't reach. Up to the ceiling, over a full room, down a shaft. You point, it measures.
• One person. No one has to hold the other end.
• Darkness and dust. It doesn't care about the light — unlike both camera apps and the machine learning that recognises doors in a scan.

What it can't do: it doesn't know which room it's standing in. It gives you a number, not a shape. You have to keep track of the order and meaning of the measurements yourself — usually on a scrap of paper that goes missing.

What the phone is good at

• Whole rooms at once. Walls, doors, windows, openings and furniture in one go.
• The relationships. How the rooms sit in relation to each other — what a floor plan is about, and something a laser can never give you.
• Areas straight away. Square metres per room, with no arithmetic.
• Speed. A home that would take a morning with a tape measure and a sketchpad can be scanned far faster.
• It's always there. You have it in your pocket when you're standing at a viewing.

What it can't do: hit the millimetre. A scan can place the wall line at the skirting board instead of at the plaster, get confused by a mirror, and drift slightly over long distances.

Work out when the difference actually matters

Example 1 — flooring for a living room. You measure the room at 4.00 × 5.00 m = 20.00 m². If the scan is 2 cm out on both sides, that becomes 4.02 × 5.02 = 20.18 m², so 0.9% too much. You'll add 5-10% wastage on top when laying it anyway, so the error disappears into the rounding. Here the phone is plenty.

Example 2 — a solid wood worktop. You order a slab for a niche you've measured at 246 cm. If the real measurement is 244 cm, the slab won't fit, and it can't be returned. Here 2 cm is the difference between "fits" and "wasted money". Measure with a laser or a tape measure — and measure the niche in three places, because walls are rarely parallel.

Rule of thumb: if the measurement is going to be cut to, measure it with a laser or a tape measure. If it's going to be multiplied up into square metres, a scan is fine.

Which kind of laser should you choose?

The device comes in three tiers, and it's the use — not the range alone — that decides which one you need:

• Simple home model. Typically reaches 20-30 metres, shows one number at a time, and can add measurements together and work out area. That's all you need to measure up rooms indoors.
• Mid-range. Longer range, memory of the last measurements, and often Bluetooth to your phone. Worth choosing if you measure many rooms in a row and are tired of writing numbers down.
• Professional. A sighting camera so you can hit a point at a distance outdoors in sunlight, an inclinometer for measuring sloped distances, and a housing that can take a building site.

So what costs extra is range outdoors, memory and phone connectivity, and ruggedness — not the accuracy indoors, which is much the same all the way up the range. Well-known brands include Bosch, Leica, Stanley and Hilti.

Bluetooth: the best of both

Many lasers can send the measurement to your phone over Bluetooth, and the manufacturer usually has a free companion app. That saves you reading off a number and typing it in — and that's actually where most mistakes happen: 2.46 becomes 2.64 because two digits swap places in your head on the way to the paper.

Not sure whether Bluetooth is worth the extra cost: it is, if you're measuring up a whole home. It isn't, if you use the meter three times a year to hang shelves.

How to use them together

1. Scan or draw the whole home on your phone. Now you have the shape, the order, and a first estimate of every measurement.
2. Pick out the measurements that cost money. Typically one main dimension per room, every doorway, and any niches you're building into.
3. Measure them with a laser or a tape measure. Measure the same spot every time — internally, wall to wall, at around 1 metre height, where there's no skirting board.
4. Write the correct numbers into the drawing. This is where many people stop too soon: an app where you can correct a measurement is worth far more than an app that can only scan again.

HouseSense is built for exactly that workflow. The home is scanned with LiDAR or drawn with your finger on a digital sheet of graph paper, and the measurements can be written in afterwards in whole centimetres as internal measurements, wall to wall, the way you'd measure yourself. Walls snap to their neighbour and become one shared wall, so two rooms never count the same square metres twice. Out comes a floor plan, areas, a takeoff for contractor quotes and reports in PDF — and it all lives in your own iCloud, with no account and no server.

So: should you buy one?

Yes, if you're building, renovating, ordering things to size, or often measuring outdoors and over long distances. The cheapest model quickly pays for itself on a single worktop that fits.

No, if what you need is a floor plan and some square metres to get quotes, compare homes or plan a layout. There the phone is better — and an ordinary tape measure covers the few measurements that need to be exactly right.