You’ve seen those strange rulers with centimeters and millimeters instead of inches. Maybe you’ve used one in science class but never really got the hang of it. Well, it’s time to get familiar with the metric ruler because it has some advantages over the standard ruler you’re used to. Don’t worry, with a little practice you’ll be reading millimeters like a pro. In this article, we’ll go over how to read measurements, make conversions, and use a metric ruler for common tasks. You’ll be surprised how easy it is once you get the basics down.

## What Is a Metric Ruler?

A metric ruler only shows the metric system measurements of millimeters and centimeters. They are also referred to as scientific rulers. A metric ruler is a measuring tool used to measure lengths and distances. Unlike imperial rulers that use inches, a metric ruler is based on the metric system of units, specifically centimeters and millimeters.

### Centimeters

One centimeter is 1/100 of a meter, a bit over 1/3 of an inch. Most metric rulers are 30 centimeters in length, divided into millimeter increments. Centimeters are used to measure items from paper clips to notebooks.

### Millimeters

Each centimeter on a metric ruler is divided into 10 millimeters. Millimeters measure very small lengths, so a metric ruler marked with millimeters can measure down to 1/25 of an inch accurately. Millimeters come in handy when measuring electronic components, fabrics, and small tools.

While imperial units are still used in some countries, the metric system is considered the global standard. So if you ever travel abroad or order items from overseas, a metric ruler will come in handy. Many schools also teach the metric system, so having a metric ruler is useful for students.

For most basic measuring needs around the home or office, a standard 30-centimeter metric ruler will suit you well. Just remember, millimeters for small items, centimeters for medium things, and meters for large measurements.

## What are the Uses of a Meter Ruler

A metric ruler is essential for any maker or DIYer. Here are the main ways you’ll put yours to use:

### Measuring Lengths

The most obvious use is measuring the length of an object in centimeters and millimeters. Whether you’re measuring fabric, wood, or the dimensions of a room, a metric ruler has you covered.

### Marking Measurements

The ruler also makes it easy to mark measurements on materials before cutting. Just line up the ruler and make your marks at the measurement points.

### Calculating Lengths

With the major increments in centimeters and minor increments in millimeters, you can easily add, subtract, multiply and divide to calculate lengths. For example, if you need to cut three boards at 28 cm each, you’ve got it figured.

### Comparing Sizes

The precise measurements on a metric ruler allow you to compare the sizes of multiple objects. You’ll know exactly which is longer, wider or taller in a snap.

### Creating Guides

Use your metric ruler to draw straight lines on materials as cutting or folding guides. The long edge of the ruler creates a perfect straight edge.

### Measuring Angles

Though not technically meant for measuring angles, a metric ruler can work in a pinch using the angles at the end of the ruler. You may need to do a little math to determine the angle measurement, but it’ll get you by.

### Converting Measurements

Finally, a metric ruler is ideal for converting between centimeters, millimeters, meters, and kilometers. With all units of measurement included, conversion is visual and straightforward.

## How to Use a Metric Ruler

To properly use a metric ruler, follow these simple steps:

### Gather your supplies

You’ll need a metric ruler, a pencil, and paper. Metric rulers typically measure in centimeters and millimeters.

### Choose what you want to measure

Decide if you want to measure the length, width, or diameter of an object. Length is the longest side, width is the side to side measurement, and diameter passes through the center of a circle.

### Place the object on the paper

Put the object you want to measure on the paper. Make sure the ruler is placed at the starting point of measurement. Align the ruler so the markings are visible and easy to read.

### Read the measurements

Read the number of centimeters first, then millimeters. Say the measurements out loud as you go to keep track. Note the markings on the paper as you measure for the most accurate reading.

### Record your results

Write down the measurements on the paper next to the object. Be sure to label what you measured, for example “Length = 8 cm, 25 mm.” Review your results to ensure accuracy before using the measurements for any calculations or projects.

## How to Read Measurements on a Metric Ruler

A metric ruler is divided into millimeters, centimeters, and meters. The millimeter, noted as mm, is the smallest unit of measurement on a metric ruler. There are 10 mm in 1 centimeter (cm) and 100 cm in 1 meter.

To read measurements on a metric ruler, start by identifying the unit of measurement you need. If measuring a small object, millimeters or centimeters are good options. For longer distances, meters are better.

Once you choose your unit of measurement, locate the markings for that unit on your ruler. Centimeter markings have vertical lines with the measurement noted, while millimeter markings have small horizontal lines. Meter markings have longer vertical lines.

Find the zero point, or starting point, of your ruler. This is on the far left side. Place the object you want to measure at the zero point. Read the number that corresponds to the ending point of your object. For example, if measuring an object that is 3 cm long, place the starting point at 0 cm and read the number at the 3 cm mark.

Be careful when measuring between units, such as 2 cm and 7 mm. Add the units together to get your total measurement. In this example, 2 cm = 20 mm. So 20 mm plus 7 mm is 27 mm total.

Double check that you have measured accurately by ensuring your starting point is at the zero mark and you are reading the correct unit markings. Take your time, rushing can lead to mistakes.

To summarize, the keys to reading measurements on a metric ruler are: choose your unit, find the zero point, place your object, read the number at the ending point, add units together if needed, double check your work. If you follow these tips, you’ll be reading that ruler in no time!

## Common Measurements in Metric Units

The metric system uses meters, liters, and grams to measure length, volume, and mass. Here are seven common metric units of measurement:

### Millimeters (mm)

Millimeters are tiny units of measurement, equal to one thousandth of a meter. They are commonly used to measure small items like the thickness of paper, the diameter of a pencil, or the size of computer components.

### Centimeters (cm)

Centimeters are 100 times larger than millimeters and are used to measure items like the length of a stapler, the height of a coffee mug, or the width of a notebook.

### Meters (m)

Meters are 100 times larger than centimeters and are used to measure things like the height of a door, the length of a room, or the distance between two street signs.

### Kilometers (km)

Kilometers are 1,000 times larger than meters and are used to measure longer distances like the length of a hike, the distance between cities, or the radius of a radio station’s broadcast range.

### Grams (g)

Grams measure mass and are used to weigh small items like a sheet of paper, a banana, or a golf ball. There are 1,000 grams in a kilogram.

### Kilograms (kg)

Kilograms measure mass and are used to weigh heavier items like a bag of rice, a gallon of milk, or a small child. There are 1,000 kilograms in a metric ton.

### Liters (L)

Liters measure volume and are used to quantify the amount of space taken up by a liquid. Common uses include measuring the amount of gasoline in a tank, the volume of a bottle of soda, or the capacity of an aquarium.

So in summary, the metric system uses logical units of measurement based on multiples of 10. The most common units are centimeters, meters, liters, grams, and kilograms. Using the metric system makes conversions and calculations simple.

## Tips for Accurate Measuring With a Metric Ruler

To get precise measurements with your metric ruler, follow these tips:

### 1. Choose the correct side

Make sure you’re using the metric side of the ruler, not the imperial inches side. The metric side will show centimeters (cm) and millimeters (mm).

### 2. Position the ruler properly

Place the ruler along the edge of the item you want to measure. Hold the ruler steady and flat against the surface. For curved edges, bend the ruler to match the curve.

### 3. Read from the correct end

Read the measurement from the end of the ruler that sits at the starting point of the item. So if you’re measuring the length of an object, read from the left end of the ruler. If measuring the width, read from the top end.

### 4. Estimate between markings

The ruler may not have a marking for the exact spot you’re measuring to. So estimate the measurement to the closest marking. If halfway between, round up to the next full marking.

### 5. Add up sections

If measuring around curves or corners, you may need to measure multiple straight sections and then add up the total. Make sure each section overlaps for the most accurate measurement.

### 6. Double check tricky measurements

For very precise measurements, check your work. Measure the item a second time to ensure the reading is correct. It’s easy to misread the ruler by one marking.

### 7. Practice!

The more you practice measuring with your metric ruler, the quicker and more accurate you’ll become. Look for opportunities to measure items in your everyday environment.

## Frequently Asked Questions About Metric Rulers

Here are some few questions and answers about a metric ruler:

### How do I read the markings?

The markings on a metric ruler increase in increments of 1 mm and are numbered every centimeter. The longer lines indicate each centimeter, the shorter lines each millimeter. Start from the left side of the ruler and count up.

### What’s the difference between centimeters and millimeters?

Centimeters (cm) and millimeters (mm) are units of length in the metric system. Millimeters are smaller, so there are 10 mm in 1 cm. Centimeters are good for measuring the length of small objects, while millimeters allow for more precise measurements.

### How do I measure with a metric ruler?

Place the object you want to measure along the edge of the ruler. Line up one end of the object with the 0 mark. Note the number of the marking closest to the other end of the object. That is your measurement in centimeters. Count the short markings in between to get the measurement in millimeters. Be sure to measure from the 0 mark for the most accurate reading.

### What if my ruler doesn’t start at 0?

Some metric rulers have numbered markings that don’t start at 0. That’s ok you can still get an accurate measurement. Simply find the numbered marking closest to one end of your object. Then count the short marks from there to the other end of your object. Add that number of millimeters to the numbered centimeter marking to get your total measurement in centimeters and millimeters.

## Conclusion

So there you have it, everything you need to know to start using a metric ruler like a pro. With just a little practice, you’ll be measuring things in centimeters and millimeters in no time. The key is remembering that the lines represent either centimeters or millimeters. Keep the different units straight, and you’ve got this. Now grab a ruler and start measuring stuff! See how far you can stretch your creativity using this handy and precise little tool.

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