Read a Measuring Tape

When it comes to construction and craftsmanship, taking accurate measurements can be the difference between a great finished product and a subpar one. Luckily, with the proper approach, using a tape measure can be a quick, easy way to get you the information you need about your project. Knowing how to use and read both a retractable measure and a traditional ribbon-style tape measure can be a major asset to anyone working with his or her hands, so learn today and start measuring!

Steps

Reading the Tape

Imperial Units

  1. Use the big, numbered markings for inches. On a tape measure labeled with imperial units, the most prominent marks are usually the one-inch marks. These are typically marked by long, thin lines and fairly large numbers.[1]
    • Every 12 inches, there will often (but not always) be a foot marking. This is usually in a different color than the other markings — often red in contrast to the normal black markings. After each foot marking, the numbers next to each inch mark will either repeat from 1 - 11 again or keep counting. This can vary from tape measure to tape measure.
    • Note that the line next to the number marks each inch, not the number itself.
  2. Use the bigger marks between two inch markings for half-inches. A half-inch mark is always centered between any two one-inch marks. It almost always has the second-longest marking (after the one-inch marks). There will be one half-inch mark between each one-inch mark, but there are two half-inches per inch.
    • Note that, starting with half-inch marks, not all lines may be labeled with numbers. In this case, you need to use the markings on either side to guide you. For example, the half-inch mark between inches three and four stands for 3 1/2 inches, even though it's not labeled.
  3. Use the smaller lines between half-inches for quarter-inches. After half-inches come quarter inches. These markings are smaller (and sometimes skinnier) than half-inches but usually bigger than the densely-packed marks around them. They are evenly spaced between each half-inch mark and one inch-mark. There are four quarter-inches in one inch.
    • Note that lines marking a quarter of an inch sometimes aren't any different in size from eighth-inch marks. In this case, keep in mind that two eighths of an inch make a quarter. Count to the second eighth-inch marking after the inch marking — this is the quarter-inch (and the line in the same spot on the other side of the half-inch mark is the three-quarter inch.)
  4. Use the small, regular marks for one-eighth-inches. Smaller still than the quarter-inch markings are the one-eighth-inch markings. These markings are centered between the inch marking and the quarter-inch marking, the quarter-inch marking and the half-inch marking, and so on. There are eight one-eighth inches per inch.
  5. Use the tiny, densely-packed marks for sixteenths of an inch. The shortest lines of all on most measuring tapes are the sixteenth-inch marks. There are 16 of these tiny marks per inch — four in each quarter-inch.
    • Note that some very precise measuring tapes will mark down to one-thirty-second of an inch or even one-sixty-fourth of an inch! Use the same pattern for recognizing these miniscule measurements.
  6. Add the inch segments to determine total length. When you are measuring a length, getting an accurate value just means seeing where the tape lines up. First, mark the spot where the measuring tape lines up with the edge of the thing you're measuring. Find the nearest inch before this point. Then, find the nearest half-inch before this point. Then, the nearest quarter-inch, and so on. Add up your inches and fractions of inches until you have an accurate measurement. This is a lot easier than it sounds — see below for an example.
    • Let's say that we've measured past the the one-inch mark, past one quarter-inch mark, and past one eighth-inch mark. To find our measurement, we need to add:
      1 (our inches) + 1/4 (our quarter-inches) + 1/8 (our eighth-inches).
    • Since there are two eighth-inches in a quarter-inch, we can rewrite this as:
      1 + 2/8 + 1/8 = 1 3/8 inches.
    • Adding fractions like 1/2, 1/4, 1/8, and so on can be tricky. If you need help, see our article on how to add fractions with unlike denominators.

Metric Units

  1. Use the big, numbered markings for centimeters. On most metric measuring tapes, centimeters are the most prominent markings. Centimeters are usually labeled with large lines and, next to each line, a number. As with inches, the line marks each centimeter, not the number itself.[1]
    • If you have a measuring tape longer than one meter (100 centimeters), usually, the meter(s) will receive a special marking as well — often in a different color than the rest of the markings. After each meter, the centimeter markings may start over again from zero or continue counting. This varies from measuring tape to measuring tape.
  2. Use the smaller markings between centimeters for 0.5 centimeters. Some (but not all) metric measuring tapes will have medium-sized marks evenly spaced between each centimeter mark. These mark half-centimeters. These marks are usually not labelled with a number.
    • The metric system is in base ten, which makes it much easier to work with decimals compared to imperial measurements. For this reason, it's usually fine to refer to half-centimeter markings in decimal terms (i.e., 1 1/2 centimeters becomes 1.5 centimeters.)
  3. Use the small, densely-packed markings for millimeters.The small, tight, narrow lines between centimeter markings represent millimeters (or one-tenth-centimeters). There are ten millimeters in a centimeter (and, thus, one thousand in a meter.)
    • If your measuring tape doesn't have 0.5 centimeter markings, the fifth millimeter after each centimeter marks the 0.5 centimeter.
  4. Add the centimeter segments to determine the total length. To measure with a metric measuring tape, first find the nearest centimeter before the distance you're measuring, then the nearest millimeter. You can use a 0.5 millimeter mark to help guide you if your measuring tape has them. Your measurement (in centimeters) will be a decimal where the tenths place is indicated by the millimeter marking. For example, see below:
    • Let's say that we measure past the 33 centimeter mark to the sixth millimeter marking. In this case, we can find our distance in centimeters like this:
      33 + 0.6 = 33.6 centimeters
    • If we wanted our distance in something other than centimeters, however, we would need to shift the decimal place to compensate. For example, let's say that we want the answer above in meters. In this case, since there are 100 centimeters in one meter, we could use a conversion factor like this:
      33.6 × 1 meter/100 centimeters = 0.336 meters
    • In general, to go from centimeters to meters, shift the decimal two places to the left, and to go from meters to centimeters, shift it two places to the right.

Taking a Measurement

This section deals with how to use the two most common styles of tape measure. If you're looking for how to read the markings on your tape measure, click here.

Retractable Tape

  1. Catch the hooked end on one side of the object you're measuring. If you're using a retractable tape measure (the kind that comes in a small metal or plastic box that automatically sucks the tape back up when you're done with it) note that the end of the tape will almost always have a small metal notch at the zero mark. This is useful for holding the tape in the right place as you measure, so you may want to start by catching it on the edge of the object you're measuring.
    • On the other hand, if you're measuring something that can't be latched on to (like, for instance, the distance across a door frame), just press this metal notch into one side of the object.
  2. Stretch the tape across your object. With the zero mark in place, pull back on the box to let more tape out. You can use one hand (or a friend) to hold the end of the tape in place as you pull it back. Let tape out until it stretches all the way across the distance you're measuring.
    • Try to keep the tape straight as you do this — if you let it sag (which is easy to do if you're measuring long distances), the results you get will be skewed.
  3. Take a reading directly from the tape. Now, look at the point where the tape meets the end of the thing you're measuring. The nearest number below the end of the tape is your number of units you're measuring and the markings between this number and the one above it correspond to fractions of the unit.
    • For example, if you are measuring across the front of your dresser and the edge of the dresser lines up right after the 24 inch marking, this means that your dresser is between 24 and 25 inches wide. If, for instance, it's three 1/8 inch marks past 24 inches, it is 24 3/8 inches wide.
    • You can also try putting a kink in the tape, then lining up this kink with the edge of what you're measuring. This is handy in certain situations, like for instance, when you're measuring into a tight corner.
  4. Use the lock switch to keep the tape at the same length. Most retractable tape measures will have a button or sliding switch that, when pressed, keeps the tape measure from being sucked back in. Some even lock automatically.[2] You can use this to easily compare the sizes of different lengths and objects. For instance, the lock feature is useful for:
    • Quickly seeing which of two objects is bigger
    • Seeing whether something will fit through a certain space
    • Keeping the tape available for multiple quick measurements
    • Keeping a certain distance "handy" to avoid having to re-measure

Manual Tape

  1. Hold one end of the tape down at the start of your distance. A manual tape measure (which looks a little like a long, skinny ribbon or a ruler made out of flexible material) lacks some of the convenient features of a modern retractable tape measure, but with the proper technique, it works just as well. To start taking a measurement, grab the "zero" end and line it up with the start of the object or length you want to measure.
    • Part of the problem with manual tape measures is that they're most useful for measuring only short differences because you have to be able to hold the zero end in place while you move the other end into position. Thus, most manual tapes won't be much longer than the human arm span. If you need to measure beyond your reach, you can try keeping the zero end of your tape measure in place with a weight or getting a friend to help.
  2. Stretch the tape across your distance. Now, take the slack of the object and lay it in a straight line across the object or distance you want to measure. Be sure to keep the tape tight to ensure an accurate measurement, but don't stretch it — most modern measuring tapes are made out of semi-flexible plastic.
  3. Take a reading directly from the tape. Just as you would with a retractable tape measure, look for the spot where the end of the object or distance you're measuring lines up with the tape measure. The distance indicated on the tape measure at this point is the distance you've measured.
    • For instance, let's say you hold one end of a tape measure in the tips of your fingers and stretch the other end all the way to the crook of your armpit to determine how long your arm is. If the tape measure stretches exactly halfway between the 27 and 28 inch markings, this means that your arm is 27.5 inches long.
  4. If measuring around a round object, pinch the tape where it overlaps. One advantage of ribbon-style tape measures over retractable tape measures is that their flexibility allows them to measure around objects. To do this, place the zero end of the tape on the object, wrap the tape all the way around it in as straight of line as possible, and note the point where the tape measure first passes the zero marking once again. This point is the distance around your object.
    • For example, if you want to find the distance around your wrist, place the zero end of the tape measure on top of your wrist, wrap the slack around and underneath, then line it up with the zero end on top. If it is, for instance, six inches at this point, then your wrist has a circumference of about six inches.


Tips

  • With contractor measuring tapes, used for measuring large areas, you often cannot get a measurement using just the tape, as the body or case of the measuring tape gets in the way. That's why these bodies are carefully designed and marked to a certain width. Look on the case body for the width indicator. Many are 3". To measure a room from one corner to the other:
    • Lay the tape on the floor and hook the end into one corner of the room.
    • Pull out the tape along the floor.
    • When you reach the other corner push the butt of the tape case into the corner (the butt or back of the case has been flattened for this purpose).
    • Take your measurement from the tape and then add the 3" for the complete width.
      • Example: Measure a space on your wall. Place the front of the tape at the start point and extend it until after you reach the stop point. Look at the tape and see the last number before the stop point, for example, 17. After the number 17, count four lines, noticing that you stop on the third longest line. That would make the total measured space 17 and 1/4 inches.

Related Articles

Sources and Citations

  1. ↑ 1.0 1.1 http://iruler.net/
  2. ↑ http://thesweethome.com/reviews/the-best-tape-measure/
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