Film tables, 8mm, 16mm, and 35mm lengths, time and speed tables.

Time/Footage for Various Film Formats

Time	Reg. 8mm	Sup. 8mm	16mm	35mm
10 sec.	3 feet	3 1/3 feet	6 feet	15 feet
30 sec.	9 feet	10 feet	18 feet	45 feet
1 min.	18 feet	20 feet	36 feet	90 feet
3 min.	54 feet	60 feet	108 feet	270 feet
5 min.	90 feet	100 feet	180 feet	450 feet
10 min.	180 feet	200 feet	360 feet	900 feet
20 min.	360 feet	400 feet	720 feet	1800 feet
30 min.	540 feet	600 feet	1080 feet	2700 feet

Feet to minutes calculator for 16mm film:
minutes=feet*40/24/60 or minutes=feet*0.0278
1 foot of 16mm is 40 frames.
100' of 16mm is 2.78 minutes, or 2 minutes and 45 seconds
400' of 16mm is 11.11 minutes, or 11 minutes and 6 seconds
1 foot of 35mm is 16 frames.
100' of 35mm is 1,600 frames. 1,600 frames/24 fps = 66.6 seconds.

http://www.intervalometers.com/resource/index.php