Thanks for bringing this up, there are a lot of varying definitions for "mile" including the following:

metric mile
statute mile
nautical mile
and many more, like the ancient Roman mile...

A good reference on measurement unit definitions can be found here:

http://www.unc.edu/~rowlett/units/dictM.html#mile

Read that page for more details, but here's a quote from the definition of "mile":

Using the international definition of the foot as exactly 30.48 centimeters, the international statute mile is exactly 1609.344 meters. (In technical U.S. usage, the statute mile is defined in terms of the survey foot and equals about 1609.3472 meters; this unit is called the survey mile). In athletics, races of 1500 or 1600 meters are often called metric miles.

So we were defaulting to the U.S. survey mile, which is calculated as (1200/3937)*5280 meters. But it really makes more sense to default to the statute mile, since that's probably what more people would be looking for. If you know you want the statute mile, you can use this page:

http://www.convertunits.com/from/statute+miles/to/meters

But we've now adjusted the default for "mile" to assume the "statute mile":

http://www.convertunits.com/from/miles/to/meters

So now 1 mile = 1 statute mile = 1609.344 meters as you would expect.

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