The fitbit calorie burn is not based just on your steps. You can have the same step count but very different calorie burn estimates and you can have a lower step day that burns more than a higher step day. Assuming you didn't log anything or use Fitbit's new GPS.... The calorie burn is based on your profile stats and how much and how fast you move each minute of the day (starting 12am). The ftbit accelerometer tracks movement in three directions--up and down, forward and back and right to left. Sometimes it will track activity and credit a calorie burn with minimal or no steps (I've seen mine do this a few times--and I was active in that time just not taking steps). Also some "steps" it may credit as walking intensity and others as running intensity. Running is credited with a higher distance per step and a higher calorie burn that minute. Fitbit categorizes whether your steps were walking or running from the movement data (I think the speed/how close steps are to each other in the minute and the up and down movement or impact are big factors). A bigger clue is the activity minutes since they are based on the calorie burn each minute. Fitbit class activity as: light/sedentary activity, moderate activity, and very active minutes. The difference between moderately active and very active can be quite small so you can see a higher calorie burn with a lot of moderately active minutes so it isn't enough just to look at your very chive minutes tile. On the Fitbit website, you can flip the very active tile and then choose "view all" to see your minutes in each activity level over the past week. The answer is usually in there.

About the "fitbit adjustment" on MFP... This is *not* your fitbit calorie burn. To see that, you need to look on the fitbit website. What it is... MFp calculates this by comparing your fitbit calorie burn so far to whatever MFP expects you would have burned so far. So if you ended up with a 323 fitbit adjustment that just means your fitbit calorie burn was 323 calories higher than MFP expected. What MFP expects: there are a couple numbers involved in this. The first is based on your Mifflin BMR (factoring in your height, weight, age and gender) and the activity level you chose on MFP. MFP multiplies your BMR by the activity multiplyer affiliated with the activity level you chose. This appears in your MFP goals page as "calories burned from daily activity"--this is what your allowance is based on and also what MFP uses to base your fitbit adjustment. The second number, any exercise you log on MFP is added onto your "calories burned from daily activity". So a fitbit adjustment is meant to correct or customize your activity level. Exercise you log here is excluded to avoid double counting the same exercise calories.

This was a great post. Thank you!

I walked 11,522 steps yesterday and it burned 323 calories but today i walked 11,800 steps I only burn 222 calories. Why is this so?

Is this looking purely at an Activity Record you made on Fitbit at beginning and end of a walk?

Or are you talking about all day steps, and this was merely the adjustment under Fitness Diary based on Fitbit daily burn?

Because that adjustment has NOTHING to do with the exercise by itself - the total day rather.

You could do a really hard run for 1 hr Thanksgiving morning and burn 500 calories on it by itself in preparing to eat more - and then rest of the day sit around much more than you normally would and lose 500 calories you'd normally burn.
You could get NO Fitbit adjustment on MFP in that case.
And in that case, you also didn't accomplish any preparation for eating more.

I walked 11,522 steps yesterday and it burned 323 calories but today i walked 11,800 steps I only burn 222 calories. Why is this so?

Is this looking purely at an Activity Record you made on Fitbit at beginning and end of a walk?

Or are you talking about all day steps, and this was merely the adjustment under Fitness Diary based on Fitbit daily burn?

Because that adjustment has NOTHING to do with the exercise by itself - the total day rather.

You could do a really hard run for 1 hr Thanksgiving morning and burn 500 calories on it by itself in preparing to eat more - and then rest of the day sit around much more than you normally would and lose 500 calories you'd normally burn.
You could get NO Fitbit adjustment on MFP in that case.
And in that case, you also didn't accomplish any preparation for eating more.

What does the adjustment has got to do with then??

That adjustment has to do with the difference between what Fitbit saw you burn in total for the day, and what MFP estimated you'd burn with no exercise.

If you do log exercise on MFP, it adds exercise to it's non-exercise estimate of daily burn, and compares that total to Fitbit's total.

Say MFP has your non-exercise daily burn as 1800, an estimate based on your BMR and your selection of work activity level.
Your deficit is 500 for 1 lb weekly.
1800 - 500 = 1300 eating goal.

Without Fitbit, you log a 300 cal workout.
Non-exercise 1800 + 300 exercise = 2100 daily burn
2100 - 500 = 1600 eating goal. (actually MFP just adds the 300 to your non-exercise eating goal).

Now with a Fitbit that reports you burned 2000 one day. MFP compares.
2000 - 1800 = 200 positive adjustment
2000 - 500 = 1500 eating goal. (actually, MFP just adds the 200 to your 1300 goal)

Now, that 200 could have been exercise, could have been extra shopping, could have burned 500 in workout, but then went to bed 4 hrs early because so tired from it.

Or maybe a combo.
You log a 300 cal workout, which replaces Fitbit's stats for that time.
MFP 1800 + 300 = 2100 daily burn estimate
Fitbit reported 2200 - 2100 MFP = 100 cal adjustment
2200 - 500 deficit = 1700 eating goal (actually, MFP just adds the 300 and 100 to your 1300 goal)

In that last case, good job, a workout, and more active too!