Heartrate and Calories

lemonlionheart

Hi everyone, I have a question about the accuracy of using a gym machine heart rate monitor to estimate calories. I will hopefully be getting a fitbit or other activity tracker at the end of the year (poor student atm), so what I've been doing to attempt to get an accurate estimate of my calorie burn at the gym is measuring my heart rate throughout on the machine sensors and using the shapesense calculator (http://www.shapesense.com/fitness-exercise/calculators/heart-rate-based-calorie-burn-calculator.aspx) to estimate the net calories burned. I've created entries in my exercises for different heart rates and at the end of every ten minutes I enter the time for that heartrate, for example,calories etc. I try to underestimate, so if the reading is between 138 and 150 during the ten minutes I will enter it as 140. Can anyone confirm that the calculator I use is accurate (enough) so I'm not crazily overestimating my burns or anything? Does anyone else who doesn't own a heart rate monitor do something similar to this? I know there is always room for error with these things but at least I know the gym sensors are fairly accurate. Thanks guys x