UKC

According to my Garmin forerunner:

15 km on a canal towpath in 1 hour 10 minutes = 1200 Cals
17 km in the hills with 1500m of ascent in 3 hours = 1100 Cals

Can these both be correct?
Is there a simple rule-of-thumb style formula that works well for hill runs?

In reply to Paul Robertson: Which forerunner? Quite a few of them are extremely inaccurate and not worth taking into account. I have a 305 and it overestimates by about 2 or 3 times too much and it just uses a basic algorithm. My Edge 800 on my bike is a lot more accurate as it uses heart rate, but you do have to know roughly what you burn and adjust the weight parameters accordingly. I.e. it is accurate for me but it doesn't work for everyone. HR is not necessarily very accurate either, it depends on the person really. The only sure way is a proper lab test along with a power meter on a bike, not much use for running.

In reply to Paul Robertson:

I copied this bit of info from some site or other. Don't know if it's correct but it would make a better assessment of your two runs!

Hills running steady pace, 600 cals an hour, on the flat 100 cals / mile.

In reply to Paul Robertson:

I don't think they're especially accurate and I don't really pay much attention to the calories. If I load my Forerunner data into Garmin Connect, Fetch Everyone, and Strava, they all come out with different calorie expenditure for the same run.

However, Strava does seem to work out the difference between runs and it kind of 'looks' right. Eg.

12.6km with 343m of ascent, 1hr 07 - 1,074 calories
13.0km with 834m of ascent, 1hr 46 - 1,606 calories

I think there are so many factors involved in accurately calculating calories including your age, weight and heart rate, and how cold it is, that this can be nothing more than an educated guess.

I just know that I run a lot and eat a lot and can hardly keep weight on so I'm easily burning enough - right another piece of cake please

In reply to Escher:
405. I think the watch just records the time and position. The calculation for Cals is done on the computer where the data is uploaded.
I don't often wear the HR monitor, but on flat runs the I get similar estimates for Cals with or without the HRM.