20 kilometers to miles
12.43 mi
20 km = 12.43 mi.
miles
12.43mi
20 km = 12.43 mi
The short answer
How many miles is 20 kilometers?
20 km = 12.43 mi. 1 kilometer = 0.621371 miles, so the working is 20 × 0.621371 = 12.43.
The working
The factor below is an exact definition rather than a measurement, so nothing is approximated in the arithmetic. The only rounding on this page happens where a number is displayed.
1 kilometer = 0.621371 miles 20 × 0.621371 = 12.43
How much precision do you need?
Each row is the same answer cut at a different number of decimals, with what that choice costs you. Pick the shortest row whose error is smaller than whatever you are measuring with.
| Rounded to | Answer (mi) | Off by |
|---|---|---|
| Whole number | 12 | −0.42742 |
| 1 decimal | 12.4 | −0.02742 |
| 2 decimals | 12.43 | +0.00258 |
Round trip: take 12.43 mi back the other way and you land on 20.0041 km — a drift of 0.0041 km. That gap is the rounding, not the conversion.
What 20 km looks like
21 km
A half marathon is 21.0975 km, exactly half the certified marathon distance.
Frequently asked questions
What is 20 kilometers in miles?
20 kilometers is 12.43 miles. 1 kilometer = 0.621371 miles, so the working is 20 × 0.621371 = 12.43.
How accurate is 12.43 mi?
Rounding to 12.43 mi and converting straight back gives 20.0041 km, a drift of 0.0041 km from the 20 you started with. The factor itself is exact; every bit of that difference comes from the rounding, not the conversion.
Nearby values
Any value at all
Km to Miles Converter
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