Millimeter
Millimeter is the metric unit of length used for measuring small objects and quantities such as medicines, length of a pen tip, etc. It is most commonly written as 'mm'. While measuring the length of any object, meter, centimeter, millimeter, and inch are used. The word millimeter means thousandth of meters. Let us learn more about this metric unit, the conversions, and solve a few examples to understand the concept better.
1.  Millimeter Definition 
2.  Convert Millimeter to Centimeter 
3.  Convert Millimeters to Inches 
4.  Convert Millimeter to Meter 
5.  Convert Millimeter to Kilometer 
6.  FAQs on Millimeter 
Millimeter Definition
A millimeter can be defined as a metric unit used to measure the length of small or tiny objects such as measuring lines, the length of a pencil tip, etc. The word is usually expressed as 'mm' and is considered to be equal to onethousandth of a meter. The metric unit consists of meters, centimeters, millimeters, and inches. Look at the image of a ruler below, the longer lines with numbers written below them indicate the value of centimeters and the smaller lines indicates the value of millimeter. Hence, 10 millimeters makes 1 centimeter.
Convert Millimeters to Centimeters
As we know a millimeter is equal to onethousandth of a meter, whereas a centimeter is equal to onehundredth of a meter and is expressed as 'cm'. On a ruler, each number is written 1 centimeter away from with 10 small lines that are 1 millimeter away from each other. mm is used to measure objects less than 1 cm. In other words, 1mm = 1/10th cm or 10mm = 1cm.
Let us look at the mm to cm conversion table to understand it better.
Millimeter (mm)  Centimeter (cm) 

1  0.1 
2  0.2 
3  0.3 
4  0.4 
5  0.5 
6  0.6 
7  0.7 
8  0.8 
9  0.9 
10  1 
mm to cm Formula
As we can see from the above conversion table 1mm = 0.1cm, we can also use a simple formula to convert mm to cm. The formula is:
d_{(cm)} = d_{(mm)} ÷ 10
Where,
 d_{(cm)} = value in centimeters
 d_{(mm)} = value in millimeters
Example: Convert 100 mm to cm
Solution: Using the formula,
d_{(cm)} = d_{(mm)} ÷ 10
d_{(cm)} = 100 ÷ 10
d_{(cm)} = 10cm
Therefore, 100mm = 10cm.
Convert Millimeters to Inches
The millimeter unit is defined in the international system of units called SI units, whereas the inches are used in the US customary system of measurements. It is very easy to convert millimeters to inches and viceversa with the help of this mm to inches formula and the mm to in conversion table. The length of 1 millimeter = 0.03937007874 inches and to convert mm we need to multiply the number with 0.03937007874 in. Hence, the formula is:
d_{(in)} = d_{(mm)}_{ }× 0.03937007874
To convert mm to inch we can also divide the length of a millimeter by 25.4 since 1in = 25.4mm. Therefore, the formula is:
d_{(in)} = d_{(mm) }÷ 25.4
Where,
 d_{(in)} = value in inches
 d_{(mm)} = value in millimeters
Example: Convert 15mm to in.
Solution: Using the formula,
d_{(in)} = d_{(mm)}_{ }× 0.03937007874in
d_{(in)} = 15 × 0.03937007874in
d_{(in)} = 0.5905511811in
Therefore, 15mm = 0.5905511811in.
Convert Millimeter to Meter
Meter is another metric unit that helps in measuring the length and is expressed as 'm'. To convert millimeter to meter, we can use both the conversion table and the formula. Since 1 cm = 10 mm, meter can be expressed in terms of millimeters as 1 m = 1000 mm. In other words, 1mm = 0.001m. Let us look at the conversion table below.
Millimeter (mm)  Meter (m) 

1  0.001 
2  0.002 
3  0.003 
4  0.004 
5  0.005 
6  0.006 
7  0.007 
8  0.008 
9  0.009 
10  0.01 
mm to m Formula
There are two formulas to convert mm to m, either multiply the value of mm with 0.001 or divide it by 1000.
d_{(m)} = d_{(mm)}_{ }× 0.001
d_{(m)} = d_{(mm) }÷ 1000
Where,
 d_{(m)} = value in meters
 d_{(mm)} = value in millimeters
Example: Convert 20mm to m.
Solution: Using the formula,
d_{(m)} = d_{(mm) }÷ 1000
d_{(m)} = 20 ÷ 1000
d_{(m)} = 0.02
Therefore, 20mm = 0.02m
Convert Millimeter to Kilometer
Kilometer is a unit of the metric system mainly used to express a distance. The abbreviation of kilometer is km. It is a unit of the International System of Units (SI units). Conversion from mm to km is simple like the other conversions. As 1cm = 10mm, we can say 1 km = 1,00,000 × 10 = 1,000,000mm since 1km = 1,00,000cm. Therefore, 1mm = 0.000001km. Let us look at the conversion table to understand it better.
Millimeter (mm)  Kilometer (km) 

1  0.000001 
2  0.000002 
3  0.000003 
4  0.000004 
5  0.000005 
6  0.000006 
7  0.000007 
8  0.000008 
9  0.000009 
10  0.00001 
mm to km Formula
Since 1km = 1,000,000 millimeters, the simple formula to convert is:
d_{(km)} = d_{(mm) }÷ 1000000
Where,
 d_{(km)} = value in kilometers
 d_{(mm)} = value in millimeters
Example: Convert 500mm to km.
Solution: Using the formula,
d_{(km)} = d_{(mm) }÷ 1000000
d_{(km)} = 500 _{ }÷ 1000000
d_{(km)} = 0.0005
Therefore, 500mm = 0.0005km.
☛Related Topics
Listed below are a few topics that are related to a millimeter.
Millimeter Examples

Example 1: Sam is having a scale of 381 mm. What is the length of scale in inches?
Solution: Given,
Length of the scale in millimeters = 381
Using millimeter to inches formula,
The length of scale in inches = (n × 0.03937)
= (381 × 0.03937) inches
≈ 15 inch
Therefore, the length of the 381 mm = 15in.

Example 2: The length of a blackboard in Jill's class is 800mm. What would the length be in centimeters?
Solution: Given,
Length of the blackboard in millimeter = 800mm.
Using the mm to cm formula,
d_{(cm)} = d_{(mm) }÷ 10
= 800 ÷ 10
= 80
Therefore, the length of the 800mm = 80cm.

Example 3: Convert 250mm to meter.
Solution: Given,
Length in millimeter = 250mm
Using the mm to m formula,
d_{(m)} = d_{(mm) }÷ 1000
= 250 ÷ 1000
= 0.25
Therefore, 250mm = 0.25m.
FAQs on Millimeter
How Many mm Means 1inch?
1in = 25.4mm. Millimeter or mm can be converted into inches and vice versa by using a simple formula.
How do you Convert mm to in?
The length of 1milimeter = 0.03937007874 inches and to convert mm we need to multiply the number with 0.03937007874 in. Hence, the formula is:
Value in inch = Value in mm_{ }× 0.03937007874
How do you Convert mm to cm?
From the article, we have learned that 1cm = 10mm. Therefore, the formula to convert mm to cm is:
Value in cm = Value in mm ÷ 10
What Size is 100mm in Inches?
We can convert mm to in by using the formula, Value in inch = Value in mm_{ }× 0.03937007874.
Value in inch = 100 × 0.03937007874
100mm = 3.937007874in.
What are Millimeters Used For?
Millimeter is used for measuring small lengths and visible distances. In real life, it is considered to be the size of a wire used in paper clips. Millimeters can be converted to other metric units such as centimeters, meters, inches, and kilometers.
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