I burn more calories in the evening doing same walk

[AuntPol]

I walked 4 miles this morning and burned less calories than I did walking 3.5 miles at a slower MPH rate in the evenings. I noticed this time and time again. If I walk 4 miles in the morning and do my typical 1.5-2 during the day, I will still need 1-2 more miles to reach my calorie goal. But if I just wait until evening to walk that 4 miles, I don't need any extra calories.

My fitbit chart says that I burn 5 calories every 5 minutes while sleeping yet I will wake up at 6 AM and have 330 caloires burned which is less than a calorie per minute that my chart says I burned. In the evening, I can go to sleep at 10 PM and be confident that I will burn 120 calories.

[RobertoME]

Hello @AuntPol, great to see you around! As you know, all your stats are related. What I mean with this is it will depend how many steps you achieved in a short period of time. If you have around 1,000 steps in this period, it means you are keeping a high pace on your exercise and by consequence you will achieved more active minutes and this will affect directly how many calories you burn during your exercise. So your tracker will detect subtle differences in exertion that may explain why two seemingly identical activities result in different totals. In example: differences in your speed and exertion levels, out of breath vs not out of breath, etc, will cause different numbers. Additionally I would like to recommend the following post from @SebringDon. You may find additional information about how calories are calculated.

Hope it helps and keep me posted how it goes.