Gee, i shouldve started running earlier -- burned 300 calories in 20 minutes ??!!

i almost think my treadmill is broken...

but anyhow, according to it, i burned 300 calories in 15 minutes...incline 2 and 5.0 to 6.0 mph the whole time

still seems hard to believe...is this accurate? :/ 

Did you put in your weight/other stats?

nope :/ my treadmill is old and doesnt let you put in stats
havent used it since......a month after i bought it... years ago

Don't know how accruate that is.... but 5-6mph is pretty fast (hahah but than its ME your whos responding here), so who knows, maybe its possible!!

The treadmill probably calculates the calories burned on the "average" man.  Depending on your hieght and weight, you may not have really burned that many calories.  Sorry :)

I really doubt that's accurate. I'm sure you burned a decent amount of cals but that sounds very high. I would estimate that you would burn 300 cals in 40 mins (not 20 mins) of running.

Suggest you don't rely on machines. Use the activity calculator on this CC site, and try this calculator on Self Magazine's website too. You have to register to use, but it's free:

http://www.self.com/fitness/calculators

Even that website overestimates for me, as compared to the numbers I get with my heart rate monitor.

I burn about 350 calories in 45 mins of spinning, which to me is pretty darn vigorous. But according to that website, MODERATE spinning for 45 mins burns 450 calories at my weight.

I have jogged at about 5 mph before (outdoors so different inclines) for about 1/2 hr and I'd say that 1/2 hr of spinning is harder. So for me at least (at 115 lbs), there's no way 15 mins of that burn 300 cals. Your number, of course, would be different if your height/weight/gender are different, but 1200 cals/hour still seems like a TON.

At incline 7 degrees, 3.8 mph, 190 pounds, I burn 400 in 34.5 minutes according to my treadmill with heart rate monitor.

I always use my own heart rate monitor (HRM) and it's definitely the most accurate measure you can have -  Next to my heart rate per minute, my average heart rate, it gives me the exact total amount of calories and how much percentage is fat.  In general, when I compare the results of my HRM to those specified by the machine there is an average difference of at least 30% between both results (being that of the machine higher and that of my monitor lower).  In your case that would be no more than 210 calories in 20 minutes -which indicates high intensity training with VERY high beats per minute -but of course this is still speculative, since I don't know your age and your health / weight conditions.  At 38, 5'6" and 63 kilo's and moderate to high intensitiy work out, I usually don't burn more than 6-7 calories per minute (and that is with a heart rate between 138-152 bpm).
 There is a direct relationship between your heart rate and your training target zone -  there is an estimated highest heart rate and depending on your training goal, you should keep your beats per  minute (bpm) in an specific range -  for losing fat, at the lower end of the range of the training zone and for endurance at the highest end of the range.  
I never train without my heart rate monitor and it's a great 'coach' which keeps me focused in the goals I want to achieve and prevents me from running out of breath or pushing it too hard.    I use it not only when doing cardio, but also when doing strength training, so I don't miss the results of that part of my routine too. As I said, the results are personalized and it's great when you want to keep a log of your physical activities in this website - with a HRM you could even get familiar with how much you burn in an hour of gardening, or cycling to work (which I do), or cleaning the house:-) 
 You can check www.polarusa.com and get more familiar with these terms and see if there is HRM model that suits your budget.

How about some really fun activities.  I went ice skating for the school field trips this week and skated 45min with each class.  CC tells me skating is over 600 cal per hour!  That is awesome.  Also looking forward to downhill skiing soon (my motivation for getting in shape) and I just looked it up 585 cal per hour!  This fitness stuff is paying off!

This should be acurate. I'm about 130 lbs, 5'4, and I run at 5.5-6 mph, and I burn about 550-650 cal/hour. The incline adds to it even more!

My parents have one of those really old treadmills with a built in incline, no way to enter your H/W/A or anything. I usually run at the gym with the new machines; and I've found that the readings on my parents machine are WAY higher than the ones at the gym.. by almost twice as much. So when I run at their house(thanksgiving, etc) I take about 200 cals at least off the meter when I input it.

Any treadmill that gives an "average" rating is sort of shooting in the dark, because you don't know what "average" it bases it on. Usually its 150 lb individual, but that doesnt take into account age or gender.

I run at a 1% incline going 6.0 (10 min a mile) and it's about 100 calories per mile. I don't think 300 calories for 30 min is bad though!

Original Post by misspriss316:

I run at a 1% incline going 6.0 (10 min a mile) and it's about 100 calories per mile. I don't think 300 calories for 30 min is bad though!

It's not at all, for me and my weight I burn about 400 calories at 6 mph at a 1% incline on the treadmill. I have a good treadmill (thank you Amazon and your no tax or shipping, lol) and being able to put in your stats really makes me feel better about the calories i'm burning.

Did you have a resistance on it? That's another factor in burning calories. Anyways, when I run on an elliptical machine after entering my stats, I burn 250 calories on 3 resistance and maybe 6mph on average with a 6 incline (doesn't mean much to me because incline on elliptical machines feel like nothing) in 20 minutes.

On a regular treadmill, you burn more with incline rather than speed, however, with the stats you give, it seems like it's unreasonable. You probably burned ~150 cals.