Using a tape measure is simple and intuitive once you get the hang of it.

Recruit a helper
Unless you’re measuring a distance that’s shorter than your arm span, taking a measurement is much easier if you have someone to help you.

Define what you’re measuring
Figure out what you’re actually measuring, as in what two points you’re using as the beginning and the terminus of your measurement. Mark them using an easily wiped-off instrument like chalk or a grease pen.

For most home uses, you’ll want to pick something you can measure straight and level—you’re not going to get an accurate sense of how wide a space you need for your new armoire if you’re including the curve of its outward-flaring doors in your measurement of the width.

Fix the first point
Take the working end of the tape measure and fasten it, as necessary, to the point you’re measuring from. Or get someone to hold it in place if it’s going to be too far for you to do it all yourself.

Extend the tape measure and fix the second point
Next, extend the tape until the exposed part of the tape reaches the point you’re measuring to. Keep the tape flat and straight. If you’re measuring a distance, keep it as level to the ground as you can.

“It’s important to keep your tape measure as straight as possible when taking measurements,”  “It’s easy to bend a tape measure, which can cause inaccuracies.”

Lock the tape measure
Lock the measuring tape’s blade in place, using the thumb slide or lock.

Read the measurement
Read the increment marking closest to the case. That’s the full measurement.

Taking measurements within measurements
If you’re also trying to find the length of two points along the measurement, note the measurement of the first point you want to measure and then the second point and simply subtract the smaller number from the larger number.

The trick to measuring a ceiling height with a tape measure
No matter how wide and rigid your tape measure blade is, you’re going to find it challenging to measure the heights of most rooms’ ceilings with a tape measure.

Thompson uses a nifty trick of the trade: “If you’re trying to measure something tall, like a ceiling or the top of a window frame, don’t just extend the tape measure and attempt to hit the high point with the metal endpiece,” she says. “Instead, step on the metal endpiece, pinning it to the floor, and extend the tape into an upside-down U shape, with the highest point of the folded tape at the high point you are trying to measure. This takes advantage of the structural strength of the tape’s shape and creates a more stable and easy way to measure.”

LaBoda, Thompson, and Mowat all agreed that a 25-foot tape measure—the kind that’s the most commonly sold in hardware stores—would work as the mainstay of most homeowners’ utility closets. They also preferred one-inch or wider blades, since the extra stiffness makes the tape less likely to flop around when you extend it to longer lengths.

If you frequently pull out tape measures on the go, however, the 25-foot tape measure can quickly start to feel cumbersome. “For carrying around (if you’re a designer or just a person who loves measuring), a 16-foot tape in a plastic case is perfect,” Thompson says. “I also carry a tiny 10-foot tape in my pencil case at all times. It’s so narrow that it can’t span long distances on its own, but it’s good for flat measurements in a pinch.”

How accurate does my tape measure have to be?
When Thompson was a designer for Apple Stores, her team measured to 1/32 of an inch—the smallest increment on a tape measure. But for the purposes of most DIY projects, the experts we consulted agree that accuracy to within a quarter inch is usually fine.

Are metal tape measures better than cloth or paper?
Though most tape measures are made of a flexible metal, it’s common to see cloth tape measures (or, if you’re building IKEA furniture, even paper). But if you want more accurate measurements, stick to metal. “When used correctly, a metal tape measure is more accurate than a cloth tape measure because its rigidity makes it easier to keep the tape straight,”