Whether you’re pounding out a DIY project that will only ever see your backyard or designing a public monument, how to read a tape measure is a pretty universally useful skill. And though the simple tape measure may be the humblest of all tools, it’s arguably the most important for crafts where even an eighth-of-an-inch flaw can throw off your entire project. To set you up for success, we asked design experts the basics about how to read a tape measure—including what all those markings actually mean, the difference between metric tape measures and those that use imperial units, and how laser measures compare to that tape measure you got for a couple bucks off Amazon.
Do I really need a tape measure?
Yes.
“A tape measure is absolutely crucial, whether you are measuring for a future piece of furniture or planning out something more detailed like a kitchen cabinet,” says Ming Thompson, principal of New Haven, Connecticut–based architectural firm Atelier Cho Thompson. “The worst certainly could happen; that expensive dresser just might not fit. Always measure twice.”
And no, that’s not just an architect being extra cautious because that’s what she has to tell students at the Yale school of architecture. North Carolina–based interior designer Heather LaBoda says a tape measure is often the first thing she reaches for when she’s working on a job, too, and that every homeowner with even a passing interest in DIY projects needs to learn how to use one. Deciding to “ballpark” measurements or work off of old architectural drawings without verifying may cost you in the long run. “You may find that your design doesn’t fit and [you] may need to make significant design changes to fix the issue, which could cost time and money,” LaBoda says.
What is the difference between a tape measure and a ruler?
Though a tape measure and a ruler look alike and serve the same purpose, you should have at least one tape measure at home at all times for most home improvement projects, as they can measure longer distances and are more flexible and accurate than the rulers you used to draw straight lines in grade school.
What are the parts of a tape measure?
As simple as the concept seems, there are several components to a modern retractable measure that you should know before you use one.
The blade
The most important part of a tape measure is the blade, or the tape, which is the part the measurements are printed on. It’s usually a thin metal ribbon. Traditionally it’s painted yellow. The tape is typically 15 to 50 feet long.
The hook
The hook is a metal L-shaped piece that’s fastened to the end of the blade. Sometimes you’ll see a slot, or one or two smalls holes, in the hook. These are called “hook slots” and are there so you can affix one end of the tape measure to something, freeing you to extend the blade beyond arm’s reach. This is invaluable if you’re trying to measure something long and don’t have a helper to assist.
What’s the difference between metric and imperial tape measures?
What your tape measure says can depend a lot on what part of the world you’re in. Despite the best efforts of President Jimmy Carter and a majority of scientists to get more Americans to use the metric system, most nonscientific linear measurements in the US are still based on the US Customary System.
So, though some tape measures will have increments in the decimal-based system of metric units—like millimeters, centimeters, and meters—the tape measures you see in the US almost always have increments in what are often (but technically, incorrectly) called imperial units: fractions of an inch, inches, and feet. Some tape measures have markings for both the metric system and the USCS system—the former commonly in red and the latter in black, at least in the US.
What’s the difference between a survey foot and an international foot? And can I still use my old tape measures?
Note that though the USCS is historically related to the oft-considered obsolete British Imperial System and still often referred to as the “imperial system” or “imperial units,” they’re distinct systems with incompatible measurements for many things.
