Ruler Measurements : How to Read like a Breeze

Ruler Measurements of different lines on a ruler can leave you perplexed, but, just don’t worry! Taking ruler measurements is really simple when you understand what you are supposed to do.

There are two types of measurement rulers

the inch ruler12 big numbers on it1 for each inch
the metric ruler30 big numbers on it1 for each centimeter

Let’s get together to walk through the basics of these two rulers to make taking measurements a breeze.

How to take Ruler Measurements

  • Reading an Inch Ruler
  • Reading a Metric Ruler

Ruler Measurements : Reading an Inch Ruler

Get an inch ruler.

12 inches equals 1 foot. Each foot is broken into inches. Each inch is broken into 15 smaller marks to make it equal to 16 marks in total. The bigger the measurement, the longer the line on the ruler. The lines decrease in size as the unit of measurement does, ranging from 1 inch to 1/16 of an inch. Ensure to read the ruler from left to right. While measuring something, align it with the left side of the zero mark on the ruler. The right side of the line where the object ends will be its measurement in inches.

Learn the inch marks.

A ruler is made up of 12 inch marks, typically the numbered marks on the ruler are denoted by the longest lines on the ruler. While measuring a nail, place one end directly on the left side of the ruler. If ending directly above the long line next to the large number 5, the nail is 5 inches long. Some rulers may denote 1/2 inches with numbers, so ensure using the largest numbers with the longest lines for inch markers.

Learn the 1/2 inch marks.

The 1/2 inch marks will be the second longest lines on the ruler, half as long as the inch marks. Each 1/2 inch mark comes midway between each inch number as half of an inch meaning that marks directly between the 0 and 1 inch, 1 and 2 inches, 2 and 3 inches, and so on, are the 1/2 inch marks. In total, there are 24 of on a 12 inch ruler.

Learn the 1/4 of an inch marks.

Halfway in between each 1/2 inch line, a smaller line denotes a 1/4 of an inch. In the first inch, marks denote 1/4, 1/2, 3/4, and 1 inch. Although the 1/2 inch and 1 inch marks have their lines, they are still part of the 1/4 of an inch measurements as 2/4 of an inch equals half an inch and 4/4 of an inch equals 1 inch. There are a total of 48 on a 12 inch ruler.

Learn the 1/8 of an inch marks.

The 1/8 of an inch marks are the smaller marks found directly in between the 1/4 of an inch marks on the ruler. Between 0 and 1 inch, there are marks that denote 1/8, 1/4 (or 2/8), 3/8, 1/2 (or 4/8), 5/8, 6/8 (or 3/4), 7/8, and 1 (or 8/8) of an inch. In total, there are 96 of these marks on a 12 inch ruler.[4]
For example, you measure a piece of fabric and the edge falls on the 6th line after the 4 inch mark, which is directly in between the 1/4 of an inch mark and the 1/2 inch mark. This means that your fabric is 4 and 3/8 inches long.

Learn the 1/16 of an inch marks.

The small lines halfway between each 1/8 of an inch denoting 1/16 of an inch, the smallest lines on the ruler. The very first line on the left hand side of the ruler is the 1/16 of an inch mark. There are marks denoting 1/16, 2/16 (or 1/8), 3/16, 4/16 (or 1/4), 5/16, 6/16 (or 3/8), 7/16, 8/16 (or 1/2), 9/16, 10/16 (or 5/8), 11/16, 12/16 (3/4), 13/16, 14/16 (or 7/8), 15/16, 16/16 (or 1) of an inch, between 0 and 1 inch. There are a total of 192 such lines on the ruler.

Ruler Measurements : Reading a Metric Ruler

Get a metric ruler.

A metric ruler is based on the International System of Units (SI), called the metric system. It is divded into millimeters or centimeters. Rulers are often 30 centimeters long designated by large numbers on the ruler. There are 10 smaller marks called millimeters (mm) between each centimeter (cm) mark. Ensure to read from left to right on the ruler. While measuring an object on the ruler, align it with the left side of the zero mark. The right side of the line where the object ends will be its measurement in centimeters.

Learn the centimeter marks.

The large numbers next to the longest lines on the ruler denote the centimeter marks. A metric ruler has 30 of these marks. For example, place the bottom of a crayon on the far left side of the ruler to measure it. Note where the tip falls. If the crayon ends directly on the long line next to the large number 14, your crayon is exactly 14cm long.

Learn the 1/2 of a centimeter marks.

Halfway between each centimeter, there is a slightly shorter line that denotes 1/2 of a centimeter, or 0.5cm. There are a total of 60 of these marks on a 30 cm ruler.

Learn the millimeter marks.

Between each 0.5cm line, there are four additional lines that denote the millimeter marks. There are a total of 10 lines per centimeter, with the 0.5cm line acting as the 5 millimeter mark, making each centimeter 10mm long. There are 300 millimeter marks on a 30 cm ruler.