Are Online Calorie Calculators Accurate?

September 15, 2014

Probably the most common thing that people seek out help for during their fitness journey is how many calories should they be eating and what  their macronutrient split should be.



For the people who aren’t my specific clients and would rather try and figure things out for themselves, I do recommend them to go to and to fill out the info and see what the calculator comes up with.

So, does that mean I think they are 100% accurate? No. Why would I recommend that then?

Because it’s simply a good starting point.

Sure, the calculator asks your height, weight, activity level, age, gender, etc. but there are SO many other factors that really do go into figuring out what works for your body.

It depends on your past dieting experience – if you dieted for a very long time on super low calories, low carbs, and a lot of cardio, then it may not be accurate. You wouldn’t want to go from 80g carbs and jump up to 220g carbs like the calculator may suggest.

It depends on your metabolism – this is similar to the above point, but your metabolism may either be MUCH slower than suggested, OR it may even be much faster than suggested.


For example, a general calculation for someone who is 90 lbs won’t get a very high amount of calories even for their maintenance. Let’s just say it comes out with 1500 calories to maintain their weight. However, that 90 lb person may already be maintaining on 2400 calories. In this case, yes, the calculator is WRONG.

It also depends on so many other factors, but we could be here all day talking about that. The best way for you to figure out the proper calorie count for your body, depending on your goal, is to first determine your maintenance calories.


Count your calories for a few days or even a week to see how much you are eating. Whatever that number is, determine if you are maintaining your weight, losing weight, or gaining weight.

If you are maintaining, you have found your maintenance calories! That means you could either keep doing what you are doing, or determine what your goal is and go from there. If you want to lose weight or fat, cut calories slowly, and if you want to gain, increase calories slowly.

If you find out how much you are eating and you are gaining, then cut calories a bit and see if your weight stabilizes to find your maintenance. And if you are losing, increase to find your maintenance calories.


Yes, it seems tedious, but that’s honestly the best way to really find out what works for YOU. You could plug your numbers in a calculator, but it wouldn’t be 100% accurate. However, if you are just starting out, you could start at that and then simply adjust from there.

Bottom line – it’s all about playing around with the numbers to find your actual maintenance calories.

Yes, the online calculators are a great place to start, especially for beginners who have very little knowledge on maintenance calories and such. BUT even from there, it’s up to you, or a qualified coach, to find the proper calorie range for you and YOUR body type. After you know how many calories you should be eating, then you figure out your macronutrient ranges. That will be an entirely different post!


Have you ever used an online calculator?

What was your experience?


    1. I am definitely one of those people who gets absolute BS results from those calculators, as we both know! Just goes to show that you really can’t reply on a number spat out by a machine to dictate how much you eat. I think your recommendation to “keep watch” for a week is the only real way to figure out what works for YOU.

      1. Yes, exactly! You were in my mind while writing up this post 🙂

    1. Great post! I use and have used calculators in the past. Most of my results didn’t help me and were obviously not right, but as you say, it is a great starting point and an EASY way to nake all these calculations. Math is not my forte! 😉

      1. Hahaha exactly! I’m sure a lot of people agree.. math isn’t the best;)

    1. Great tips, Brittany, thank you!!
      So far I let my coaches do the calorie work, but I would love to know myself how much I burn/need on a given day!

    1. sometimes I think that labels in general are wrong – that’s why just eating good natural foods is more dependable for sure!

    1. Great article!! Wondering the reason behind counting macros vs just counting calories for weight loss?

      Thank you!

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