How to Read a Tape Measure and Understand Its Markings

5 tape measures on workbench

There are many tools you can have in your arsenal. One of the most common tools is definitely the tape measure. Most people assume that you can simply pick up a tape measure and use it. However, there are correct and incorrect ways to use a tape measure. But where do you even begin learning to read a tape measure?

Answering that question is essential, and it’s why we put together this handy guide. This hand tool can make your life easier, but it is important to know how to read a measuring tape properly. Even an error of 0.1 inches can be quite disastrous for certain projects. Accuracy is particularly important when building something with little wiggle room for adjustment, such as woodworking. Wrong measurements could waste hundreds of dollars in materials. That’s why it’s best to learn how to read a tape measure.

Tape measure markings and what they mean

A tape measure’s markings correspond in height to each fraction of an inch. The tallest lines are for 1/2-inch markings, and the line heights are shorter for each smaller fraction measurement down to 1/16 of an inch. Credit: Nathan Hamilton

The best tape measures for people living in the U.S. are ones with inch and foot markings. This is known as the imperial system. It is the standard form of measurement used by most handymen and DIY enthusiasts in the U.S.

The readings on a measuring tape are usually 16 marks to the inch, which means you can read up to 1/16 of an inch. However, some tapes can measure from 32 to 64 marks to an inch. The below list details how to easily read a tape measure and explains each marking from the biggest to the smallest fraction of an inch.

  • One foot or 1’ lines – At each interval of 12 inches, tape measures will include a number that shows the number of feet. The common way this is displayed on the blade is 1F for one foot.
  • One inch or 1” lines – Tape measure markings at 1” intervals will have the tallest vertical line that usually spans the entire blade width. There are 12 inches in one foot.
  • Half-inch or 1/2” lines – The next marking you should know is the half-inch mark. It can be easily located in the middle of any two one-inch markings. Half-inch markings also have a shorter vertical line than one-inch markings. There is only one half-inch marking per inch.
  • Quarter-inch or 1/4” lines – Halving any half-inch marking will get you measurements for every quarter of an inch.
  • Eighth-inch or 1/8” lines – The next line marking is the eighth-inch tape measure marking.
  • Sixteenth-inch or 1/16” lines – If you look at the first line after a one-inch mark, it’s the sixteenth-inch mark. The smallest line denotes it.

How to read a tape measure in practice

Once you know what each mark represents, learning how to read a measuring tape properly won’t be a problem. Suppose you are measuring a piece of wood. You place the small metal hook, called the tang, at the start of the workpiece and slide the measure all the way to the other side of the plank. Then, simply see which line on your tape measure corresponds with the edge of the piece of wood.

Suppose it is the fourth line between 10 and 11 inches. If your tape measure has 1/16-inch intervals, it would denote a quarter-inch, and your measurement becomes 10 and ¼ inches or 10.25 inches.

LEARN MORE >> How to Use a Tape Measure

Standard inch notations

Another thing you need to know is the standard way to write a value in inches is to add a quotation mark directly after the number. A piece of wood measuring 20 inches would be written as 20”. The table below is also a handy guide to common notations and conversions.

FractionIn DecimalsIn Words
1/16″0.0625 inchesSixteenth of an inch
1/8″0.125 inchesAn eighth of an inch
1/4″0.25 inchesA quarter of an inch
1/2″0.5 inchesHalf of an inch

 Laying out common stud and joist locations

Copy of Tape Rows 7
Top photo: The red-highlighted box is included at 16-inch intervals to help lay out studs for walls. Bottom photo: The diamond on a tape measure is included at 19.2-inch intervals to help lay out floor joist locations. Credit: Nathan Hamilton

What does 16 inches on center mean?

To easily strike measurements for stud locations, most tape measures include markings to make this process consistently accurate. Most tape measures feature a highly-visible red marking at 16-inch intervals. These tape measure markings correspond to standard stud locations for building walls. This is what’s referred to as “16 inches on center.”

What does the diamond on a tape measure mean?

The small black diamond on a tape measure is used to lay out measurements for floor joists at 19.2-inch intervals. The black diamonds indicate the center portion between two joists.

Bottom Line

It will take you some time before you can easily and quickly read the markings on a tape measure and get an accurate reading. But learning how to use a tape measure is not rocket science. With just a little practice, you will eventually be able to read the markings for accurate measurements. Always aim to get the most accurate readings when measuring an object. Remember, it is better to measure twice and cut once.

Picture of Nathan Hamilton
Nathan Hamilton
Nathan Hamilton is the founder of DIY Gear Reviews and a recognized expert in the home and DIY space. He has over 200 bylines covering topics such as power tools, hand tools, and woodworking. Nathan is the strategic director for DIY Gear Reviews, deciding everything from the content covered to designing the testing methodologies for lab-tested reviews. He can be emailed at


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