How Many Calories Do I Burn A Day: The Most Accurate Method

Whether you want to lose weight, gain weight, or maintain your weight, the first thing you need to figure out is how many calories you burn a day.

Why?

Because when you know how many calories you burn a day, you can determine how many calories you need to eat a day.

So the question is, what’s the best method for figuring this out?

Well, for starters, it’s none of the methods you think.

Let me explain…

The 4 Ways You Burn Calories

The first thing you need to know is that there are 4 factors that contribute to the total amount of calories you burn over the course of a day. They are:

Basal Metabolic Rate (BMR)
This is the amount of calories your body burns at rest just keeping you alive and functioning. So, imagine the number of calories you’d burn if you stayed in bed all day not moving or digesting food. That’s your BMR, and it accounts for the majority (typically 60% – 70%) of the calories your body burns each day. While most of this calorie burn comes via your organs, the amount of body fat and muscle mass you have also play a big role, as both are metabolically active. Meaning, your body burns calories maintaining all of your fat and muscle. For this reason, the more you weigh, the more you’ll naturally burn.
Thermic Effect of Activity (TEA)
This represents all of the calories your body burns each day via exercise. Weight training, cardio, sports, and anything similar fits into this category. This can obviously vary quite a bit from person to person, as some people exercise more than others.
Thermic Effect of Food (TEF)
This is defined as the calories your body burns during the digestion and absorption process of the foods you eat, and it typically accounts for around 10% of your total metabolic rate. TEF is influenced by the total amount you’re eating (the more you’re eating, the more your body ends up burning to process it all), as well as the macronutrient composition (protein, fat or carbs) of what you’re eating, as your body burns more calories digesting certain nutrients than it does digesting others (protein has the highest TEF).
Non-Exercise Activity Thermogenesis (NEAT)
This is the calories burned as a result of all of the activity taking place over the course of the day BESIDES exercise (source)… which includes unconscious, spontaneous daily movement (i.e. the seemingly minor movements you make throughout the day that you didn’t consciously plan to make). So everything from brushing your teeth, to walking to your car, to typing, to shopping, to fidgeting, to adjusting your posture, and much more fits into this category. NEAT actually accounts for a surprisingly significant amount of the calories that people burn each day, though it can vary quite a bit (we’re talking hundreds of calories) from one person to the next (source).

When you combine these four factors together, you get what’s referred to as your Total Daily Energy Expenditure (TDEE)… also known as your maintenance level.

This is the total amount of calories your body burns each day, and that’s the number you’re reading this article to figure out.

Which brings us to the next obvious question…

How Do You Accurately Track How Many Calories You Burn A Day?

So now we know the 4 factors that contribute to the amount of calories we burn.

That’s wonderful.

But um, how do we accurately track all of these factors and determine what this total amount actually is?

A calculator?
An app?
A wearable device? (e.g. FitBit, Apple Watch, Whoop, Oura Ring, etc.)

What’s the best way to accurately track it all?!?

Ready for the honest answer that you’re going to hate?

There Is No Accurate Way To Track Calories Burned

Unfortunately, no method of tracking calories burned is truly accurate.

In fact, most have been shown to be highly inaccurate. (More about that below.)

Not being aware of this inaccuracy, or even worse, adjusting your diet based on inaccurate data for how many calories you’re supposedly burning, can lead to all sorts of problems.

You know, problems like eating significantly more or less than you should be. Or the problematic concept of “eating back the calories burned“. Or just driving yourself nuts trying to accurately track something that can’t be accurately tracked.

But wait, what’s that you say?

What About Calculators, Apps, And Wearable Devices?

What about all of these tools that were created for this exact purpose?

Yeah… about them… they all have issues with accuracy.

Calculator Accuracy

You know those TDEE/calorie calculators where you enter in your age, sex, height, weight, and activity level, and they tell you how many calories you burn (or how many calories you should eat based on its estimate for how many you burn)?

Well, studies (like this one) and years of real-world experience have shown that they’re off by hundreds of calories for many (but not all) people.

Diet And Fitness App Accuracy

Every app that does any sort of TDEE calculation is typically using the very same equation being used in whatever random TDEE calculator you can Google and find. Which means it will have the very same issues with accuracy.

Wearable Device Accuracy

What about all of the “smart” wearable devices? Turns out they’re not so smart in this regard.

A variety of studies (sources here, here, here, here, and here) show they all suck at tracking calories burned. Most are good enough for tracking steps and heart rate, though.

Just not calories burned.

That Doesn’t Make These Methods Useless

Try as we might, any data we have for how many calories we’re supposedly burning isn’t going to be as accurate as we want it to be.

Does that make all of these methods useless? Nope.

They can still be of some use.

For example, if you want to use this data as some kind of rough ballpark estimate for how many calories you MIGHT be burning, that’s totally fine.

You just can’t rely on it to be anything more accurate than that, and I definitely wouldn’t make adjustments to my diet based on that data.

And if you want to use one of these methods – like a TDEE calculator – to help you come up with an estimated starting point for how many calories you should be eating a day, that’s totally fine as well.

In fact, I recommend it.

But again, you can’t rely on that calculator to give you anything more than an estimated starting point. It could be a lot higher or lower than you actually need, so adjustments will probably be needed.

So, that’s all of the bad news about trying to track calories burned.

Now for the good news…

The Best And Most Accurate Method

Despite the fact that the most common methods for figuring out how many calories you burn a day aren’t accurate enough to rely on for that purpose, there is one super simple method that most people aren’t even aware of.

It also happens to be the best and most accurate method of them all:

The best way to figure out how many calories you burn a day is by tracking your daily calorie intake along side the trend of what your body weight is doing as a result of this calorie intake.

This combination of data will tell you everything you need to know about how many calories you’re burning.

Here’s exactly what that means:

Estimate Your Calorie Needs
First, you need to come up with some kind of estimate for how many calories you should be eating a day. Feel free to use whatever method you want for this purpose, like a TDEE calculator. The exact one you use doesn’t matter. The exact equation it uses doesn’t matter. Whether you pick the “right” activity level when using that calculator doesn’t matter. All that matters is that you come up with some kind of starting estimate for how many calories to eat a day.
Eat That Amount
Then, start eating that amount of calories every day. Be as consistent as you can.
Track Your Body Weight Correctly
Weigh yourself every day, first thing in the morning before eating or drinking. At the end of the week, take the average, and then only pay attention to what your weekly averages are doing over time.
Repeat
Do this for the next 4 weeks.
Look At What’s Been Happening
At that point, look at what your body weight has been doing while eating this amount of calories.
Do Some Basic Math
All it takes now is some basic math to accurately figure out how many calories you burn a day, keeping in mind that there are about 3500 calories in a pound of fat.

Let me give you two examples of how this “basic math” would work…

Example #1

Let’s say you’ve been eating 2000 calories a day and your weekly body weight averages have stayed about the same for the last 4 weeks.

This would mean you’re probably at your maintenance level (i.e. you’re eating and burning the same amount… no deficit or surplus exists), which means you can safely assume that you’re burning around 2000 total calories a day.

Yes, even if some app, calculator, or wearable device says otherwise.

Example #2

Now let’s say you’ve been eating 2000 calories a day and you’re consistently losing about 1lb a week for the last 4-5 weeks. You can now assume that you’re probably burning 2500 total calories a day.

Why? Because there are about 3500 calories in a pound of fat.

(Details here: How Many Calories In A Pound Of Fat)

So if you’re consistently losing 1lb per week, it would mean your total weekly deficit is about 3500. And if you divide that 3500 weekly deficit by 7 days in a week, you can see that you’re in a 500-calorie deficit per day.

So if you’re eating 2000 calories a day, and that represents a 500-calorie deficit, that would mean you’re burning 2500 calories a day.

Pretty simple.

I know what you’re probably thinking, though.

Isn’t This Also Just… An Estimate?

Yup. Of course it is.

In this context, damn near everything is “just an estimate.”

How many calories you’re eating.
How many calories you’re burning.
Your body weight.
Your measurements.
Your body fat percentage.

It’s ALWAYS just estimates.

All you can do is rely more on the estimates that have a higher degree of accuracy, and less on everything else.

And in this case, that would mean relying waaaay less on estimates for how many calories you’re supposedly burning accordingly to various calculators, apps, and wearable devices, and more on tracking a combination of calories consumed + the trend of what your body weight is doing.

Looking at those two metrics over time will tell you everything you need to know about how much you’re burning, when some kind of adjustment needs to be made (if any), and exactly what that adjustment should be.