Charge 3 calories accuracy

[Gooneyz]

I've been working to lose weight and am using my calories burned on Fitbit as a base point. How accurate are these numbers? I'm 6'5" 280lb male. I went on a 6.3 mile ~1000 vertical ft hike today and the workout said I burned ~1900 calories. How do I know how accurate these numbers are?

Moderator Edit: Clarified subject

[AlejandraFitbit]

Welcome to the Forums, @Gooneyz.

Fitbit devices combine your basal metabolic rate (BMR)—the rate at which you burn calories at rest to maintain vital body functions (including breathing, blood circulation, and heartbeat)—and your activity data to estimate your calories burned. If your device tracks heart rate, your heart-rate data is also included, especially to estimate calories burned during exercise. The number you see on your Fitbit device is your total calories burned for the day.

Your BMR is based on the physical data you entered in to your Fitbit account (height, weight, sex, and age) and accounts for at least half the calories you burn in a day. Because your body burns calories even if you’re asleep or not moving, you see calories burned on your device when you wake up and will notice this number increase throughout the day.

Let me know if  you need anything else.