RPM to MPH on stationary Bike!

So I was at the gym today and wasnt paying attention to the bike I was riding. I am trying to track calories burned and I dont recal how many MPH I was going but I was going at an RPM of 71-75. Is there a way to convert this? I tried to Google it and it is way over my head mathmatically!

THANKS

It probably depends on your resistance settings.  If you know your distance and time your could figure it out from there.

I was on a level 2 out of 10 on resistance. I went 5 miles over 20 minutes...

I think that sounds right.

5 miles in 20 min is 15 MPH, paul is right, the RPM to MPH really depends on resistance.

Thanks! I appreciate the help. Next time I will change it from RPM to MPH on the machine so I can track it. Oh and it would help if I paid more attention to it! LOL

I would recommend, if your bikes have the option, to track your workout via watts or wattage versus RPM. An engine in a car in first gear at 4000 RPM is going WAYYYYYY slower than the same car in 5th gear at 2500 RPMs. I wouldnt worry too much about speed in an indoor setting anyways, just go workout based on RPE (Rate of percieved excersion) on a scale from 1-10. For good cardiovascular training 2-6 is your aerobic or fat burning zone, over that is anaerobic and can only be sustained for short periods of time (max 3 minutes) Try working in aerobic zones while incorporating some anaerobic bursts.