Are my calories for a walk too high?-Versa

[Mikkuni]

I took a walk this morning, like I always do, and it was about an hour and 40 minutes. I got 10,000 steps. I'm not sure the exact distance since it doesn't seem to tell me in the exercise log but I have gotten 7.12km total today and I take my walk first thing in the morning so most of that should be from the walk. I did stop in the grocery store so at least part of the walk was at a much slower pace. Average heart rate of 122bpm, peaking at 153 at some points. I do not walk on perfectly flat grounds and I do walk up some stairs. I'm a 29 year old female. 167cm (5'6'') and 59kg (130lbs). 

My fitbit tells me I burned 588 calories for this walk (6 calories per minute). Is this actually accurate? My husband says this is way too high but most places I look seem to agree an hour walk should be about 300 calories. 

Thoughts?

Moderator edit: updated subject for clarity

[EdsonFitbit]

Welcome to the Fitbit Community, @Mikkuni.

Thank you for the information provided.

To make sure that your Fitbit Versa is working as intended, please perform a restart by following these steps.

In addition, please visit this article, open the menu "What are some tips to make sure my Fitbit daily activity is accurate?"  and follow the instructions.

For information on how your Fitbit device calculate calories burned, please visit this site.

Hope this helps.