Is my crosstrainer telling me the wrong kilojules burned?

anaik96

Hi I've recently started exercising and I've been using my crosstrainer (it's only a cheap one and fairly old) but it has a heart rate monitor and tells me how many kilojules burned but I think it's wrong. I recently did 30 mins on interval and it said I burnt 3906 kilojules! That's 933 calories! Surely that can't be right? Help would be greatly appreciated