Knowing how to accurately read an analog scale is essential to any business that calculates prices and costs based on weight. All the lines on a scale may seem confusing, but they are not difficult to read once you know how.

Digital vs. Analog Scale

A digital scale uses a power source to turn the force of the weight on it into an electrical signal. The weight is displayed in backlit numbers on a small screen. An analog scale has a spring inside it, calibrated to move a dial or needle when weight is put on it. The needle moves to a number or a line between numbers to indicate the weight.

Grocery store scales, such as the kind found in a produce department, are an easy-to-use analog scale that helps customers estimate the weight and cost of their purchases. Weighing scales in pounds are found in a variety of businesses, most often to calculate prices of items sold by weight and to calculate mailing and shipping costs.

Advantages of an Analog Scale

Using an analog scale for your business has several advantages. Analog scales are often more affordable than digital versions. Because they don't require a power source, either from a battery or an electrical outlet, they can be used almost anywhere. Analog scales are not as sensitive to moisture. They may have faster response times than digital scales, which is important when it is necessary to weigh multiple items in quick succession.

Reading the Lines on an Analog Scale

The lines on a retail analog scale represent the fractions of the unit of measurement indicated by the numbers. Suppose a scale is designed to measure up to five pounds. Between each of the numbers one through five, there are lines that show fractions of a pound. By counting the number of lines between any two numbers, you can determine the smallest unit of measure.

U.S. Standard System vs. Metric System

In the U.S., grocery store scales, postage scales and other types of scales used in small businesses generally measure weight in pounds and ounces, called the U.S. Standard System. A weighing scale in pounds and fractions thereof is used to calculate postage and shipping weights. It's the system learned by U.S. schoolchildren and, therefore, most easily understandable by many customers. The metric system, which uses the gram as the basic unit of measurement, is often used by companies that do business internationally.

Understanding Units of Measure

When you recall standard units of measurement, you can understand how scale manufacturers determine how many lines to place between the numbers on a scale. For example, there are 16 ounces in a pound. A small scale that measures in pounds and ounces can have as many as 15 lines between the one and the two, between the two and the three and so forth. The whole numbers represent the pounds and the lines represent the ounces.

A scale that uses the metric system will subdivide units in multiples of 10. For example, there are 1,000 grams in a kilogram (about 2.2 pounds). Since it would be impossible to read a thousand tiny lines, a metric unit of measure will be subdivided in a way that is both useful and makes sense. In a retail spice shop, for example, a scale might measure up to half a kilogram (500 grams). There might be 10 subdivisions, each of which indicates 50 grams.

Different Line Lengths

Scale manufacturers use different line lengths to make it easier to read the fractions of the unit of measurement. On a small scale that measures in pounds and ounces, there is a long line in the middle of any two numbers. That represents half a pound, or eight ounces. Each half pound is further subdivided with a shorter line that indicates quarter pounds, or four-ounce increments. The smallest lines indicate each ounce.

Examples of an Analog Scale Reading

Say you're weighing a mailer on a small postage scale that measures every ounce up to two pounds. After placing the envelope gently on the scale, the needle moves to the third small line after the zero. The mailer weighs three ounces. Perhaps you put a small package on the scale and the needle moves to the first small mark after the halfway mark between one and two. You now have a pound (16 ounces) and another half pound (eight ounces). The small mark indicates an additional ounce, so your mailer weighs 25 ounces, or one pound, nine ounces.

Choosing the Right Scale

It's important to choose the right scale for your needs. For example, if you're mailing letters, brochures and flyers, you need a scale that measures in ounces. If you're selling tea or spices in a retail environment, you'll probably be measuring the product in ounces or even grams, a smaller measurement. Shipping very heavy items requires a scale that weighs in pounds and half pounds.