How accurate is your Heart Rate Monitor?

It is difficult to comment on without knowing how long did you work out? And how much do you weigh? How old are you? Your weight has a lot to do with your burn rate.

If 45 minutes then that implies you were working out at over 20 calories/minute which is getting up there a bit...As a 63 yo 170 lb male who does a reasonable amount of cardio I would not be able to maintain 20 cal/min for 45 minutes. Maybe I could go 10 minutes... I don't know...

If 90 minutes then you're at a little over 10 calories/minute. That's a more reasonable rate but most classes don't last that long do they?

We need more data.

Edited to add: I did a google search of Timex HRMs and it seems like a lot of people are commenting upon the high calorie burn numbers they are getting.

950 calories per 70 minutes would average out to about a 13.5 cal/min burn rate. That rate seems reasonable but I don't do that type of cardio so I'm a little out of my league here.

My gut reaction is that the calories burned number you got seems a tad bit high but would certainly be achievable given the right person and circumstances, etc., etc. blah, blah, blah... LOL

One test you could do if you know someone in the class who also has a HRM: Swap HRMs and then compare the readings you got between the two on two days when you did roughly the same class. (It would be a better test if the other HRM was not a Timex.)

With certain classes (like Body Pump), I burn about 650 in 50-60 minutes. So, I would say it could be possible if it was a pretty hard work out.

Mine is dreadful. Consistently cuts out, and on the rare occasions it does, gives me calorie burns far higher than any other estimate. I just use it to monitor my heart rate - but should really just get a better one!