Calories burned discrepancy between my activities-Versa 2

[Rusty82]

Hi all, firstly I hope you’re all doing well and staying active! I’m reaching out for some advice/tips/thoughts on my versa 2 which was gifted to me recently. I’m having a hard time understanding the calories burned during activities undertaken, in particular the accuracy. For example, if I do an intense 2hr plus session on my stationary watt bike, my average BPM is 144-150 and according to Fitbit I’ve only burned circa 1200-1300 calories. However, if I walk briskly for the same amount of time with an average BPM of 120 I’m burning circa 900-1000 calories and the bike session is SO SO SO much more intense (literally dripping with sweat), the walk is really easy by comparison. If I use an online calculator for calories burned based solely on BPM then I should be burning 1700-1800 calories for the same 2hours plus watt bike session? Can anybody here explain what I should be more inclined to believe? Many thanks.

Moderator edit: updated subject for clarity

[EdsonFitbit]

Welcome to the Fitbit Community @Rusty82.

Thank you for the information provided.

Our team has recently released a new firmware version for your Fitbit Versa 2 (35.72.1.9). If you have received the notification to update, please follow these instructions.

Since your calories burned are estimated based on your Basic Metabolic Rate (BMR), your activity data and your heart rate, please make sure the physical data you entered in to your Fitbit account (height, weight, sex, and age) is correct. For instructions on how to manage your Fitbit profile, please visit this article, open the menu "How do I change my birthdate, sex, height, or weight?" and follow the instructions.

For information on how your Versa 2 does calculate your daily activities, please visit this site.

Whether you continue experiencing difficulties, please restart your watch by following these steps.

Please make sure to follow this guide to wear your Versa 2.

If you have any question, please let us know.