irunner without hrm

TheYoungys

Hi all, first time I've posted but have a question. I usually use irunner for my runs, hikes and cycling but I don't have a hrm. I usually use it because it tells me info about routes and elevation (I am a hill runner). When I come home and plug in the stats to MFP it is usually off to the tune of 30-40 cals. So, my question is, which is more accurate? Yes, I know I should buy a HRM but finances are tight so I haven't yet. Just want an accurate tally without one right now.
Any ideas?