Rulers are an essential tool come have, but if you’re struggling with just how to read a ruler, you"re no alone. There room so countless lines ~ above a ruler, the can get confusing to number out what they every mean.

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In this guide, we’ll explain why you should know just how to review a ruler and give girlfriend step-by-step indict on how to read a ruler in inches and cm. We’ll also provide you v some beneficial resources you deserve to use to keep honing her ruler-reading skills.

Why You must Know just how to check out a Ruler

Knowing exactly how to check out a leader is important, not just for college but also for everyday life.

For example, if you want to do something out of building and construction paper, you"d likely need to use a ruler to measure up out exactly how much that the product you would need. Or what if you wanted to structure a photograph you have? In this case, you can have to measure up the photo to view what type of structure it would fit in.

The truth is the there are loads of moments in life once you’ll need to know just how to read a ruler. and if you don’t know how to check out a ruler, climate you’ll likely suffer part consequences. For instance, what if girlfriend make two pieces of something that don’t right together due to the fact that one is much shorter or much longer than the was supposed to be? Or what if you mess up a science experiment since you didn’t accurately read the measurement of a piece of string you cut?

It’s pretty obvious that knowing just how to review a ruler is necessary to not simply your grades in school but additionally your day-to-day life.

How to check out a Ruler: imperial vs Metric

There space two species of rulers you can use: the inch, or imperial, ruler and also the centimeter, or metric, ruler.

Inches exchange mail to the imperial system, i beg your pardon is the key measuring device used in the US and also a smattering of other countries.

Meanwhile, centimeters are part of the metric system, which is used approximately the world in both day-to-day life and also science.

While we will be offering pictures you deserve to use to monitor our instructions, we recommend gaining out your very own ruler or measure up tape for this reason you deserve to follow along in actual time.


How to check out a leader in Inches

Let’s begin by feather at exactly how to review a ruler in inches. If you’re American, this is the measure you probably know much better than centimeters, which room sometimes had on your standard 12-inch, or 1-foot, ruler (we’ll go over exactly how to review a ruler in cm in the next section).

Here’s a photo of an inch ruler:


Right away, girlfriend should have the ability to tell that this ruler uses inches, as it’s split into 12 same spaced areas (labeled 1-12), and we understand there space 12 customs in a foot (ignore the cm below).

Now, an alert the lines in between each inch, v some longer and some much shorter than others. Every of these tiny lines to represent a portion of one inch. There room five various lengths of present in total.

Each customs is separated into 16 lines, an interpretation that the an are between every line is 1/16 customs long—this is the smallest size you can measure v a ruler. (Note that part rulers only go under to 1/8 inch lines, whereas rather go under to 1/32 customs lines.)

The customs is the greatest unit top top a ruler and also is stood for by the longest line. Each 1-inch line is labeled v a number indicating what inch it is on the ruler (as the image above shows).

Example: If you were to measure up the length of a sheet of computer system paper, the item of file would come approximately the 11-inch mark on your ruler, indicating the it"s precisely 11 inch long.

The second-biggest unit on a leader is the 1/2 inch, i m sorry is represented by the second-longest line. These frequently aren"t labeled yet might be on part rulers (in which instance you"d view numbers such together 1 1/2 in, 2 1/2 in, etc.).


The 1/2-inch line is situated midway in between every inch on a ruler. The midpoint in between 7 and 8 inches, for instance, would be 7 1/2 (or 7.5) inches.

Example: If you were to measure up the width (instead that length) the a piece of computer system paper, the piece need to come up specifically to the 1/2 inch line in between 8 and also 9 inches, indicating the the broad is 8 1/2 (8.5) inches.

The third-biggest lines on a leader are the 1/4 inch lines, which appear midway in between the 1/2 inch and also whole inch lines:


If girlfriend counted in 1/4 customs on a ruler, you"d view that the fourth line after ~ 0 inches equates to 1/4 inch, the eighth line equals 2/4 (1/2) inch, and also the 12th line equals 3/4 inch.

Example: speak you’re measure up a item of cloth and also the ruler ends at the 4th line ~ the 10-inch mark. This would average that the cloth is 10 1/4 (10.25) inch long.

Next is 1/8 inch, which is the second-smallest unit the a ruler. The 1/8 currently are discovered midway between each 1/4-inch line:


If girlfriend counted in 1/8-inch increments, you"d find that the second line ~ 0 amounts to 1/8 inch, the fourth line 2/8 (1/4) inch, the 6th line 3/8 inch, the eighth heat 4/8 (2/4 or 1/2) inch, the 10th heat 5/8 inch, the 12th heat 6/8 (3/4) inch, and the 14th heat 7/8 inch.

Example: speak you decide to measure the size of a corn top top the cob. You uncover that your ruler comes to the second line after the 6-inch mark. This would mean that the corn is 6 1/8 inch long.

Finally, the smallest unit ~ above a leader is 1/16 inch.These tiny lines that represent 1/16 inch come in between all 1/8-inch lines:


If girlfriend counted each line within the first inch of a ruler, you’d acquire the adhering to measurements:1/16 inch2/16 (1/8) inch3/16 inch4/16 (1/4) inch5/16 inch6/16 (3/8) inch7/16 inch8/16 (1/2) inch9/16 inch10/16 (5/8) inch11/16 inch12/16 (3/4) inch13/16 inch14/16 (7/8) inch15/16 inch

Example: she trying to measure the size of your guideline finger. The ruler involves the saturday line previous 3 inches. This would average that her finger is 3 7/16 customs long.

Inch Ruler practice Questions


Look at the image above. What measurement, in inches, is that showing?If a pen comes to the 14th heat after 5 inches, just how long is it?


11 3/4 inches5 7/8 customs (also acceptable: 5 14/16 inches)


How to read a ruler in Centimeters

Now the we’ve looked at how to read a ruler in inches, let’s walk over just how to check out a ruler in cm.

This is particularly important to understand if she studying scientific research (recall the science normally uses the metric system—not the imperial system). Knowing just how to check out a ruler in centimeter is likewise helpful for human being who"d prefer to not occupational with fountain (which you should do v inches) and also who"d like to occupational with other units instead (in this case, millimeters).

The typical metric leader is 30 centimeter long. Each centimeter is labeled with a number to present the measure up it"s referring to. You might see inch on the various other side of her metric ruler. In this case, refer to the instructions over to learn just how to read a ruler in inches.

Also, be conscious that30 centimeter does not straight equal 12 inches, even though lock are regularly put ~ above the same ruler!

Now then, here"s what a common metric ruler looks like:


You can tell the this is a metric ruler since it’s separated into 30 same spaced sections and has "cm" written on it(ignore the inches below).

Like the inches ruler, you will do it see tons of present on a metric ruler, through some longer and also some shorter. Each line represents 1 millimeter, which is equal to 1/10 or 0.1 cm (so 10 mm consist of 1 cm).

There will constantly be 10 lines from one centimeter to the next centimeter. In total, there room three various lengths of lines on a metric ruler.

The longest heat represents the best unit top top the ruler: 1 cm. each centimeter is labeled on the ruler (1-30).

Example: friend take out a ruler to measure the broad of her fingernail. The ruler stops at 1 cm, an interpretation that your nail is specifically 1 cm wide.

The middle-length heat on a metric ruler is the 1/2 (0.5) centimeter line, which come midway between every centimeter (in various other words, it"s the 5th line ~ every entirety centimeter):


So if girlfriend counted five lines native 9 cm, for instance, you’d get 9.5 centimeter (or 95 mm).

Example: to speak you"re measuring the broad of your smartphone, and also it comes approximately the 5th line after ~ 4 cm on your ruler. This would mean that the phone call is 4.5 cm (45 mm) wide.

The smallest unit a metric ruler deserve to measure is 1 mm, or 0.1 cm. These are the smallest lines on the ruler, that is, the ones that come between the totality centimeter and 1/2 centimeters:


Within the an initial centimeter alone, every line from 0 would equal the following:1 mm (0.1 cm)2 mm (0.2 cm)3 mm (0.3 cm)4 mm (0.4 cm)5 mm (0.5 or 1/2 cm)6 mm (0.6 cm)7 mm (0.7 cm)8 mm (0.8 cm)9 mm (0.9 cm)10 mm (1 cm)

Example: you’re measuring the length of a strand that hair. The strand pertains to the 9th line ~ 16 cm on the ruler. This would mean the strand is 16.9 cm long (that’s 16 cm + 9 mm).

Centimeter Ruler practice Questions


Look in ~ the photo above. What measurement, in centimeters, is the showing?You’re measure a pair that glasses, native the end of one lens come the far finish of the other lens. Your ruler reaches the seventh line past 12 cm. Exactly how long is the pair that glasses?


24.1 cm12.7 cm (or 127 mm)

6 added Resources for finding out to check out a Ruler

If you want any type of extra assistance with learning how to check out a leader in centimeter or inches, videos and also worksheets have the right to be fantastic resources.

Here room two easy-to-follow videos come further help you learn how to review a ruler:

How to check out a ruler in Inches

How to review a ruler in cm

If you’d rather test out your ruler-reading knowledge with practice questions, climate it’s a good idea to download free measurement worksheets native these mathematics sites:

All of these resources, in enhancement to the grasp of exercise questions we offered you above, need to be sufficient to gain you analysis a leader in no time in ~ all!

What’s Next?

Got questions about decimals and fractions?Our skilled guides will certainly teach you just how to transform decimals to fractions and how to include and subtract fractions.

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Metric rulers usually have actually only centimeters and millimeters on them. But go you recognize there"s an also tinier unit called nanometers? Learn how to convert nanometers come metersand other dimensions with our in-depth guide.

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