Miles (mi) and Kilometers (km) Conversion Calculator

An online miles and kilometers conversion calculator is presented along with conversion formulas, examples, and practical word problems.

Common abbreviations:

Conversion Formula of Miles into Kilometers [1]

By international agreement:

\[ 1 \text{ mile} = 1.609344 \text{ kilometers} \] \[ 1 \text{ kilometer} = \left(\frac{1}{1.609344}\right) \text{ miles} \approx 0.62137119223 \text{ miles} \]

Reference: NIST Reference Guidelines

Examples of Conversion

Example 1

Convert \( 22.4 \, \text{miles} \) to km and round the answer to the nearest km.

View Solution
\[ 22.4 \, \text{miles} = 22.4 \times 1.609344 \, \text{km} = 36.0493056 \, \text{km} \]

Rounding to the nearest km (nearest unit):

\[ 36 \, \text{km} \]

Example 2

Convert \( 17.01 \, \text{km} \) into miles and round the answer to the nearest tenth of a mile.

View Solution
\[ 17.01 \, \text{km} = \left(\frac{17.01}{1.609344}\right) \text{miles} \approx 10.56952398 \, \text{mi} \]

Rounding to the nearest tenth of a mile (one decimal place):

\[ 10.6 \, \text{mi} \]

Use of the Converter

Enter the number of miles (mi) or kilometers (km) to be converted and calculate.

mi         km
km         mi
Decimal Places

Problems Involving Miles to Kilometers Conversions

Problem 1

The fuel efficiency of a car is \( 54.8 \, \text{mpg} \) (miles per gallon). What is the fuel efficiency of this car in kilometers per gallon (km/g)? Round the results to 2 decimal places.

View Solution

Convert \( 54.8 \, \text{miles} \) into km:

\[ 54.8 \, \text{mi} = 54.8 \times 1.609344 \, \text{km} = 88.1920512 \, \text{km} \]

Rounding to two decimal places gives:

\[ 88.19 \, \text{km/g} \]

Problem 2

The speed limit on a highway is \( 110 \, \text{km/hr} \). What is the speed limit in miles per hour (mph) rounded to the nearest unit?

View Solution

Convert \( 110 \, \text{km} \) into miles:

\[ 110 \, \text{km} = \left(\frac{110}{1.609344}\right) \text{mi} \approx 68.350831 \, \text{mi} \]

Rounding to the nearest unit gives:

\[ 68 \, \text{mph} \]

Problem 3

How long does it take a car to cover a distance of \( 210 \, \text{miles} \) at the average speed of \( 90 \, \text{km/hr} \)? Write the answer in hours and minutes to the nearest minute.

View Solution

Since the speed is given in km/hr, convert the distance into kilometers first:

\[ 210 \, \text{mi} = 210 \times 1.609344 \, \text{km} = 337.96224 \, \text{km} \]

Using the formula \( \text{Time} = \dfrac{\text{Distance}}{\text{Speed}} \):

\[ \text{Time} = \dfrac{337.96224 \, \text{km}}{90 \, \text{km/hr}} \approx 3.755136 \, \text{hr} \]

Convert the decimal hour part into minutes:

\[ 0.755136 \times 60 \, \text{minutes} \approx 45.30816 \, \text{minutes} \]

Rounding to the nearest minute:

\[ 3 \text{ hours and } 45 \text{ minutes} \]

More References and Links

  1. NIST Reference Guidelines
  2. Online Calculators
  3. Units Conversion and Calculators
  4. Geometry Calculators
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