Metric Units of Length Conversion

Examples of conversion between metric units of length are presented. A table based on the SI prefixes used with units is used to convert between metric units of length such as centimeters, millimeters, meters, etc.

More exercises with solutions are presented at the bottom of the page.

Table of Conversion

The table of conversion is shown below. The factors under the arrows are factors of multiplication in going from a given unit to another unit on its left.

For example, in going from millimeter to centimeter, there is a factor of 10 under the arrow, hence:

1 centimeter = 10 millimeters

Another example, in going from micrometer to decameter, the factors under the arrows are:

We now combine all factors and write:

1 decameter = 1000 × 10 × 10 × 10 × 10 micrometers = 10,000,000 micrometers

Metric Units of Length Conversion Table
Table 1 - Metric Units of Length Conversion Table

Factors of Conversion From the Table of Conversion

Table 1 above is used to determine the factor of conversion in order to convert from one unit to another.

Example 1

Convert \( 2.1 \text{ km} \) (kilometer) into \( \text{dam} \) (decameter).

View Solution

In what follows, we use the abbreviation \( \text{km} \) for kilometers and the abbreviation \( \text{dam} \) for decameter.

Using the factors in Table 1 above, kilometer which is to the left of decameter is given by:

\[ 1 \text{ km} = 10 \times 10 \text{ dam} = 100 \text{ dam} \]

which may be written as:

\[ 1 \text{ km} = 100 \text{ dam} \]

The above equality gives the following factors of conversion:

\[ \displaystyle \frac{1 \text{ km}}{100 \text{ dam}} = 1 \quad (I) \]

and

\[ \displaystyle \frac{100 \text{ dam}}{1 \text{ km}} = 1 \quad (II) \]

The above factors of conversion are used to convert \( 2.1 \text{ km} \) to \( \text{dam} \).

Write:

\[ 2.1 \text{ km} = 2.1 \text{ km} \times 1 \]

Substitute \( 1 \) by \( \displaystyle \frac{100 \text{ dam}}{1 \text{ km}} \) which is the factor of conversion (II) found above because it is equal to 1:

\[ 2.1 \text{ km} = 2.1 \text{ km} \times \displaystyle \frac{100 \text{ dam}}{1 \text{ km}} \]

Note that we have used factor (II) with \( \text{km} \) in the denominator so that it cancels with the \( \text{km} \) in the given \( 2.1 \text{ km} \).

Cancel \( \text{km} \) on the right:

\[ 2.1 \text{ km} = 2.1 \cancel{\text{ km}} \times \displaystyle \frac{100 \text{ dam}}{1 \cancel{\text{ km}}} \]

Simplify:

\[ 2.1 \text{ km} = \frac{2.1 \times 100 \text{ dam}}{1} \]

Evaluate:

\[ 2.1 \text{ km} = \displaystyle \frac{2.1 \times 100 \text{ dam}}{1} = 210 \text{ dam} \]

Example 2

Convert \( 1,200,000 \text{ nm} \) (nanometer) into \( \text{dm} \) (decimeter).

View Solution

Nanometer \( \text{nm} \) is smaller than decimeter \( \text{dm} \) and therefore using the factors in Table 1 above going from \( \text{nm} \) to \( \text{dm} \), we write:

\[ 1 \text{ dm} = 1000 \times 1000 \times 10 \times 10 = 100,000,000 \text{ nm} \]

which may be written as:

\[ 1 \text{ dm} = 100,000,000 \text{ nm} \]

From the above we can write two factors of conversion:

\[ \displaystyle \frac{1 \text{ dm}}{100,000,000 \text{ nm}} = 1 \quad (I) \]

and

\[ \displaystyle \frac{100,000,000 \text{ nm}}{1 \text{ dm}} = 1 \quad (II) \]

Since we are given \( \text{nm} \) and we need to cancel them, we use the factor of conversion (I) because it has \( \text{nm} \) in the denominator which may be canceled.

The question in this example is to convert \( 1,200,000 \text{ nm} \) to \( \text{dm} \). Hence:

\[ 1,200,000 \text{ nm} = 1,200,000 \text{ nm} \times \displaystyle \frac{1 \text{ dm}}{100,000,000 \text{ nm}} \]

Cancel \( \text{nm} \) on the right:

\[ 1,200,000 \text{ nm} = 1,200,000 \cancel{\text{ nm}} \times \displaystyle \frac{1 \text{ dm}}{100,000,000 \cancel{\text{ nm}}} \]

Simplify:

\[ 1,200,000 \text{ nm} = \displaystyle \frac{1,200,000 \times 1 \text{ dm}}{100,000,000} \]

Evaluate:

\[ 1,200,000 \text{ nm} = 0.012 \text{ dm} \]

Examples with Solutions

Example 3

Convert \( 170 \; \text{dam} \) into \( \text{cm} \)

Example 4

Convert \( 12,500 \; \text{mm} \) to \( \text{hm} \)

Example 5

Convert \( 0.0023 \; \text{cm} \) into \( \text{nm} \)

Example 6

Convert \( 890,000 \; \mu\text{m} \) to \( \text{hm} \)

Exercises

Part A

Use Table 1 above to determine the factors of conversion and convert:

  1. \( 0.0102 \text{ Mm} \) to \( \text{hm} \)
  2. \( 0.3 \text{ nm} \) to \( \text{mm} \)
  3. \( 1200 \text{ m} \) to \( \text{Mm} \)
  4. \( 13200 \text{ dm} \) to \( \text{km} \)
  5. \( 0.002 \text{ Gm} \) to \( \text{km} \)
  6. \( 13200 \; \mu\text{m} \) to \( \text{dm} \)
  7. \( 0.003 \text{ dam} \) to \( \text{mm} \)
  8. \( 0.001 \text{ cm} \) to \( \text{nm} \)

More References and Links

  1. Convert Units of Measurements
  2. Factor of Conversion of Units
  3. Units Conversion and Calculators