Sure you can spend you hard earned cash to have a high-tech sports science testing unit punish you to calculate your VO2 Max. Or, you can simply click on this link, shared recently by a club-mate of mine, John.
http://www.ntnu.edu/cerg/vo2max
I’ve never done a proper VO2 test so I can’t say how accurate or not it is, but a few friends who’ve done both say it isn’t too far off the mark. See what you make of it.
Carbon Addiction 