This app estimates your energy expenditure from running or walking, based on a GPS track or a track generated by an application such as google maps or mapmyrun.
To download a track from mapmyrun: Pop up the route in your browser. On the right-hand side of the screen, under ROUTE INFO, do Export this Route. In the pop-up, click on the tab that says EXPORT AS KML, then do DOWNLOAD KML FILE.
If you don't have a file handy, but want to try the software, right-click on this link to download the file sample.kml, then upload it using the form below.
After you click the submit button, it may take a little time for the results to be displayed. This will happen if the elevation profile for your route is not included in your input file, and therefore has to be downloaded from a database.
The method used to calculate the energy expenditure is from Minetti et al. "Energy cost of walking and running at extreme uphill and downhill slopes," J. Applied Physiology 93 (2002) 1039, and is based on laboratory data from elite mountain runners on a treadmill. YMMV, and probably most of us are far less efficient than these guys. I find the data most useful if I want to compare one run to another, e.g., if I want to know how a mountain run with lots of elevation gain compares with a flat run at a longer distance.
This software is open source, and if you prefer to run it on your machine rather than through a web interface, you can do that from the unix command line.