Tips for taking accurate measurements
Taking accurate measurements is a skill that is largely taken for granted but a highly important skill to learn. The same rules apply if you're planning to measure for mirror, windows, glass or any other material.
Measurements can be taken with a tape measure, the measuring scale on a level, a ruler, a sqare and many other things that have measuring scales printed on them. An example of a typical English measuring scale is shown below.
The line on the tape represented with the:
A = The Whole inch mark. The number to the left of the full line represents the number of full inches from the end of the tape or measuring scale. Whole inches are measured with the full line that extends form the top to the bottom of the measuring scale, or the tallest line representing an increment on the tape. Line A represents one inch or 1" in this diagram. The proper notation for inch measurements is the quotation symbol (").
B = The Quarter inch mark. Lengths in quarter inch increments are marked with these lines on the scale. Notice there are two lines of this length in between each whole inch mark. The quarter inch measurement is counted from the whole inch mark to the first quarter, to the half, to the three-quarter and to the next whole inch mark. Line B represents a length of 1 inch and 1/4, or 1 1/4" inches in this diagram.
C = The Half inch mark. The halfway point between the whole inch marks are referenced with the line centermost between the whole inch marks. This is the second longest and second easiest mark on the tape measure to locate. There are two half inch increments to each whole inch on the measuring scale. Line C represents 1 inch and 1/2 inch, or 1 1/2" in this diagram.
D = The Sixteenth inch mark. The shortest of these marks on most tape measures is the 1/16th mark. There are four 16ths of an inch per quarter inch, and there are eight such marks between each whole inch on the measuring scale. Sixteenths are typically counted from the nearest quarter or eigth inch from the left and added to the total measurement. Line D represents 1 inch 11/16 or 1 11/16" in this diagram. In this case, the 1/16 mark represented by line D is to the right of the 5/8 mark. If measuring in sixteenths, 5/8 = 10/16 plus one sixteenth to the right equals 11/16.
E = The Eighth inch mark. if you learn to identify the 1/16th mark mentioned above, you will notice the second shortest line in the measuring scale next to each 1/16th mark. These marks represent eights of an inch. The 1/8 inch increments between the whole inch marks from left to right are the 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8. The bold notations are lengths represented directly with the 1/8" mark. The others are represented with their own respective, longer markings on the measuring scale. Line E represents 1 inch and 7/8 inch, or 1 7/8" in this diagram.
Remember: The smallest marks on any measuring scale provide the most precise measurements. When reading a tape measure, it is important to identify the marking nearest to the edge of the object being measured. If an object measures between two 1/16 marks, it is better to split the 1/16th measurement into a 1/32nd increment. When using a measuring tape, it is also very important to hold the tape tightly so that the measurement is not caused to become inaccurate due to slack in the tape. The shortest (and most accurate) distance between two points is measured with a straight line.
Adding and subtracting measurements adhere to standard math practices for adding and subtracting fractions In short, we do this by converting both fractional measurements to have a common denominator, performing the math function, and then converting the resulting fraction to the lowest possible denominator.
To measure an area by square foot: One square foot is twelve inches long and twelve inches wide. 12 x 12 = 144. Measure up your length and width dimensions. Multiply length in inches by width in inches, then divide by 144. (Length X Width) / 144 = your number of square feet.
These instructions are for using an English tape measure and not for taking metric measurements without a conversion. Convert inches to centimeters using the following: 1 inch = 2.54 centimeters. Convert centimeters to inches: 1 centimeter = 0.39 inches.
Measuring glass can be tricky. If you're measuring glass for a broken window, you must account for the amount of glass concealed by the sash or frame it is contained within. A "daylight" measurement, or visual glass opening is not a sufficient measurement for cutting glass to replace a broken pane of window glass.
