Mine is about 7 miles round-trip in Chicago, because I do most of the distance on a train...
1) Ride a mile to the METRA; fold the bike.
2) Relax for an hour.
3) De-train, unfold, ride 3 miles to work.
The return trip is a mile shorter.
I've done this for over 20 years, year-around. Studded tires in the winter. Now "partly" retired, I do it twice a week.
I actually have made the entire trip by bike a few times; once on the folder so I could say "I did it", and a couple times on my road bike. It's the "Bike-to-Work Century". (Not sustainable!)


"Fair Weather" Bike


Snow Bike