Metric measuring tapes show centimeters divided into 10 millimeters. Measuring tapes that show inches use marks to divide inches into quarters, eighths, sixteenths and thirty-seconds. Many tape measures have markings only at sixteenths of an inch, but you can still estimate thirty-seconds by judging when a length falls halfway between two 1/16-inch marks. If a tape measure has 1/32-inch markings, you can read it more precisely. Some tape measures show both metric and inch marks, so look on the side with inches to find thirty-seconds.
Look for the longest lines on the tape measure, which are usually drawn all or most of the way across the tape measure and have large numbers beside them. These indicate whole inches.
Find the next-longest lines located halfway between the inches. Even if they're not marked, they indicate half inches. Look for shorter lines halfway between the inch marks and the 1/2-inch marks. They indicate quarter inches.
Count the number of spaces between an inch mark and a 1/4-inch mark. If there are two spaces, the measuring tape is marked in 1/8 inches, and it will be difficult to measure objects accurately in thirty-seconds. If there are four spaces, the tape measure is marked in 1/16 inches. If there are eight spaces, it's marked in 1/32 inches.
Lay the start of the tape measure at one end of the object you want to measure and see where the other end of the object comes on the tape measure. Look first at the number beside the last inch line before the end of the of the object; that's the number of inches. To see how many thirty-seconds the object is in addition to the inches, count the number of 1/32 lines beyond the inch mark.
If the tape measure is only marked in 1/16 inches, count the number of 1/16 lines, multiply by two and add one if the length is half of the distance toward the next mark. For example, an object that is three lines beyond the 3-inch mark on a tape measure marked in thirty-seconds would be 3 and 3/32 inches long. An object that is exactly 7 lines beyond the 4-inch mark on a tape marked in sixteenths would be 4 and 14/32 inches long.
David Thompson began writing for eHow in 2009. He has written how-to articles on home improvement, carpentry, cabinet making and gardening.