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Kilometers to miles (km to mi)

To convert kilometers to miles (km to mi): one kilometer is 0.62137119 miles, so 8 km is 4.97097 mi.

Swap units: mi to km

In miles4.97097 mi

Conversion factor Exact by definition. The inch has been exactly 2.54 cm and the pound exactly 0.45359237 kg since the 1959 international yard and pound agreement, so these are not measurements that can drift.
1 kilometer = 0.6213711922 miles
The other way
1 mile = 1.609344 kilometers
Working
8 x 0.6213711922 = 4.97097
8 km in every unit
8,000,000 mm 800,000 cm 8,000 m 8 km 314,961 in 26,247 ft 8,748.9 yd 4.971 mi 4.3197 nmi
kilometers to miles
kmmi
10.621371
21.24274
53.10686
106.21371
2515.5343
5031.0686
10062.1371

How the Unit Converter works

One kilometer is 0.6213711922 miles. Both units are defined against the same SI base unit, so the factor is derived from two exact definitions rather than measured. It is exact in principle and does not land on a round number.

Worked through: 10 km x 0.621371192 = 6.21371 mi.

Going the other way, one mile is 1.609344 kilometers.

For mental arithmetic: Multiply by 6 and drop a digit: 80 km becomes 480, so about 48 miles. True answer 49.7.

Derived rather than definitional: both are defined against the meter, and the ratio 1.609344 falls out of that. The Fibonacci coincidence is useful: consecutive Fibonacci numbers approximate the conversion, so 5 km is about 3 miles, 8 km is about 5, and 13 km is about 8.

Precision is worth matching to the input. A measurement given as 1 km carries one or two significant figures, and reporting its conversion to six implies a precision the original never had.

Unit Converter FAQ

How many miles are in a kilometer?

0.62137119. The factor is derived from the definitions of both units against the same SI base, so it is exact in principle but not a round number.

What is 8 km in miles?

4.97097 mi. Multiply by 0.62137119: 10 km x 0.621371192 = 6.21371 mi.

How do I convert miles back to kilometers?

Divide by 0.62137119, or equivalently multiply by 1.609344. One mile is 1.609344 kilometers. The two factors are reciprocals, so you only need to remember one of them.

Is there a quick way to do this in my head?

Multiply by 6 and drop a digit: 80 km becomes 480, so about 48 miles. True answer 49.7. It is close enough for everyday use.

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