# Convert 21 miles to kilometers

How many kilometers are 21 miles?

miles (mi)
21 miles = 33.796 kilometers

## Precise decimal and fraction answers

The conversion in kilometers rounded to six significant decimal places is 21 mi = 33.796224 km. The precise fraction answer is 33 1223/1536 km.

### Decimal Precision

Conversion from one to ten decimal places

• 21 mi = 33.8 km
• 21 mi = 33.80 km
• 21 mi = 33.796 km
• 21 mi = 33.7962 km
• 21 mi = 33.79622 km
• 21 mi = 33.796224 km
• 21 mi = 33.7962240 km
• 21 mi = 33.79622400 km
• 21 mi = 33.796224000 km
• 21 mi = 33.7962240000 km

## How many kilometers are in a mile?

There are 1.609 kilometers in one mile. A mile is 1.609 times longer than a kilometer. A kilometer is 62.14% of a mile

## Miles to kilometers conversion factor and formulas

Formula

The conversion factor between miles and kilometers is 1.609. This represents the ratio of kilometers per one mile. To calculate the value in kilometers, we can either multiply by the conversion factor or divide by its inverse.

### Multiplication

To convert from miles to kilometers, multiply miles by 1.609.
The formula is expressed as:
mi × 1.609 = km

### Division

Alternatively we can divide by the inverse conversion factor to get the same result.
The inverse of 1.609 is 1/1.609 or 0.621. To convert from miles to kilometers, divide miles by 0.621.
The formula is expressed as:
mi ÷ 0.621 = km

To convert 21 miles to kilometers, multiply 21 miles by 1.609.
21 mi × 1.609 = 33.796 km

## How long are 21 miles?

Real world scale examples to visualize the length of 21 miles / 33.796 kilometers

• The same width of the English Channel (21 mi)
• 79% of the length of a marathon race (26.6 mi)
• 10% of the distance from London to Paris (214 mi)

Converting miles to kilometers is a conversion between units from separate unit systems - miles are US Customary / UK Imperial defined units while kilometers are metric (SI) .

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Customary/Imperial Unit

The mile is a measure of distance between two points used within the US Customary and British Imperial units of measure. It is customarily used to measure large geographical distances. The mile is officially defined as 5,280 feet, 1,760 yards or 1,609.344 meters. The abbreviation or for miles is 'mi' or sometimes 'm' as in miles per hour. The mile's origin stems from the Roman mile, which marked the distance the Roman army could march over 1,000 (mille) paces.

SI Unit

Within the SI (metric) system of measurement, the kilometer is officially defined as being equal to 1,000 meters. It is commonly used as measurement for geographic distances in similar circumstances where a mile would be used in the U.S. Internationally it is spelled 'kilometre' whereas the U.S. spells it 'kilometer'. The symbol for a kilometer is km however k is sometimes used.

## Reverse this conversion

Convert from kilometers to miles instead.

## 21 miles to other length units

### Metric

• 21 mi = 33.796 km
• 21 mi = 33,796.224 m
• 21 mi = 337,962.24 dm
• 21 mi = 3,379,622.4 cm
• 21 mi = 3.38×107 mm
• 21 mi = 3.38×1010 µ
• 21 mi = 3.38×1013 nm

### Imperial/U.S.

• 21 mi = 21 mi
• 21 mi = 36,960 yd
• 21 mi = 110,880 ft
• 21 mi = 1,330,560 in

## References and Citations

1. National Institute of Standards and Technology (NIST) General Tables of Units of Measurement
2. International Bureau of Weights and Measures (BIPM) The International System of Units (SI)

## Decimal conversions for 21 mi to km

mi km
21.01 mi 33.812 km
21.02 mi 33.828 km
21.03 mi 33.845 km
21.04 mi 33.861 km
21.05 mi 33.877 km
21.06 mi 33.893 km
21.07 mi 33.909 km
21.08 mi 33.925 km
21.09 mi 33.941 km
21.1 mi 33.957 km
21.11 mi 33.973 km
21.12 mi 33.989 km
21.13 mi 34.005 km
21.14 mi 34.022 km
21.15 mi 34.038 km
21.16 mi 34.054 km
21.17 mi 34.07 km
21.18 mi 34.086 km
21.19 mi 34.102 km
21.2 mi 34.118 km
21.21 mi 34.134 km
21.22 mi 34.15 km
21.23 mi 34.166 km
21.24 mi 34.182 km
21.25 mi 34.199 km
21.26 mi 34.215 km
21.27 mi 34.231 km
21.28 mi 34.247 km
21.29 mi 34.263 km
21.3 mi 34.279 km
21.31 mi 34.295 km
21.32 mi 34.311 km
21.33 mi 34.327 km
21.34 mi 34.343 km
21.35 mi 34.359 km
21.36 mi 34.376 km
21.37 mi 34.392 km
21.38 mi 34.408 km
21.39 mi 34.424 km
21.4 mi 34.44 km
21.41 mi 34.456 km
21.42 mi 34.472 km
21.43 mi 34.488 km
21.44 mi 34.504 km
21.45 mi 34.52 km
21.46 mi 34.537 km
21.47 mi 34.553 km
21.48 mi 34.569 km
21.49 mi 34.585 km
21.5 mi 34.601 km
mi km
21.51 mi 34.617 km
21.52 mi 34.633 km
21.53 mi 34.649 km
21.54 mi 34.665 km
21.55 mi 34.681 km
21.56 mi 34.697 km
21.57 mi 34.714 km
21.58 mi 34.73 km
21.59 mi 34.746 km
21.6 mi 34.762 km
21.61 mi 34.778 km
21.62 mi 34.794 km
21.63 mi 34.81 km
21.64 mi 34.826 km
21.65 mi 34.842 km
21.66 mi 34.858 km
21.67 mi 34.874 km
21.68 mi 34.891 km
21.69 mi 34.907 km
21.7 mi 34.923 km
21.71 mi 34.939 km
21.72 mi 34.955 km
21.73 mi 34.971 km
21.74 mi 34.987 km
21.75 mi 35.003 km
21.76 mi 35.019 km
21.77 mi 35.035 km
21.78 mi 35.052 km
21.79 mi 35.068 km
21.8 mi 35.084 km
21.81 mi 35.1 km
21.82 mi 35.116 km
21.83 mi 35.132 km
21.84 mi 35.148 km
21.85 mi 35.164 km
21.86 mi 35.18 km
21.87 mi 35.196 km
21.88 mi 35.212 km
21.89 mi 35.229 km
21.9 mi 35.245 km
21.91 mi 35.261 km
21.92 mi 35.277 km
21.93 mi 35.293 km
21.94 mi 35.309 km
21.95 mi 35.325 km
21.96 mi 35.341 km
21.97 mi 35.357 km
21.98 mi 35.373 km
21.99 mi 35.389 km