Statute miles to runway visual range Is there a formula to converting statute miles to runway visual range? If so, what would it be? I'm seeing how 1 mile is equal to 5000 feet, but I am so confused because 1/2 of a mile is equal to 2,400 feet. I would think 1/2 would be 2500 feet. If it was half of a mile, you would take 5000 and divide that by .5 or 1/2 to get 2500. (I'm not a pilot yet)
Memorization.  This is the FAA definition:

Vis / RVR
1 SM / 5000
3/4 SM / 4000
1/2 SM / 2400
1/4 SM / 1600


This and a few more are spelled out in the Airman's Information Manual, TBL 5−4−1, RVR Value Conversions