Why are TDEE calc results so different?

SkyKC253

Each calculator online for TDEE gives me too many different answers.

Scooby calc says my TDEE is around 2600. IIFYM says around 2170 (That seems low for someone who works out daily and has a high BMI - that would mean at my goal weight I can't each very much to maintain.....)That is an insane difference in TDEEs. Anyone know which calculator online is more accurate? I'd really like to know my TDEE so that I can better know what my true deficit is.

WBB55

Any calculator is just an average of a particular theory. No one knows their own TDEE without logging, weighing and tracking results. Then you won't need calculators anymore once you have your own real data to go off of.

SkyKC253

WBB55 wrote: »

Any calculator is just an average of a particular theory. No one knows their own TDEE without logging, weighing and tracking results. Then you won't need calculators anymore once you have your own real data to go off of.

So do you see how much you lost over the course of a week and then just figure out how much you ate and how much you burned? I guess then I would add what I burned per day to what I ate and that would be my TDEE... It makes sense in my head just not in words now..

moe0303

SkyKC253 wrote: »

WBB55 wrote: »

Any calculator is just an average of a particular theory. No one knows their own TDEE without logging, weighing and tracking results. Then you won't need calculators anymore once you have your own real data to go off of.

So do you see how much you lost over the course of a week and then just figure out how much you ate and how much you burned? I guess then I would add what I burned per day to what I ate and that would be my TDEE... It makes sense in my head just not in words now..

Your TDEE should be equal to your BMR plus your activity. In other words, If you set MFP to maintain, then logged your exercise activity accurately, the average calorie allotment per day should be your TDEE. Keep in mind that some of those calculators factor in a deficit which is usually some percentage of the TDEE (like 15-20%). Something like a FitBit might be a lot easier.

WBB55

So let's say this month you eat exactly 2000 calories per day for 30 days (and you measured on a digital scale and found accurate entries). You lost 4.9 lbs in that 30 days. Your TDEE for that 30 days was 2570 or so. Let's say. By doing this, you'd determine that Scooby's is the one that will probably track you best for now. But now you've lost weight, so your TDEE is lower than it was 30 days ago. Put your new weight in Scooby's calculator, and it'll be pretty close to your TDEE for the next 30 days.

cwolfman13

SkyKC253 wrote: »

Each calculator online for TDEE gives me too many different answers.

Scooby calc says my TDEE is around 2600. IIFYM says around 2170 (That seems low for someone who works out daily and has a high BMI - that would mean at my goal weight I can't each very much to maintain.....)That is an insane difference in TDEEs. Anyone know which calculator online is more accurate? I'd really like to know my TDEE so that I can better know what my true deficit is.

Are you sure you put your goal to maintain with the IIFYM calculator? Those two calculators have always been fairly close for me.

As other's have stated, these calculators simply provide a rough estimate of your TDEE...nobody is going to have a TDEE of exactly XXXX calories...and really, since every day is not the same, your TDEE is really a range of calories rather than one specific number. These calculators provide you with a reasonably good starting off point provided you have entered everything correctly and as accurately as possible...but really, it comes down to you ultimately making adjustments as per your real world results.

marm1962

They are different because each uses a different calculation to arrive at the total -- http://www.sailrabbit.com/bmr/, this site shows 6 different ones with 4 of them using your body fat % if you know it. It also let's you use the average of the total

cgrout78

I just ran them both and had a 200 calorie a day difference...I put 3-5 hours a week down on Scooby for exercise, and 5 hours of exercise with a sedentary job on IIFYM.

so not as big of a difference, but 200 calories a day can add up...