Advanced BMR Calculator
If your health and wellness goals include losing, gaining, or maintaining your weight, it’s helpful to learn how to calculate your caloric needs. Knowing how many calories you need can help guide your food and activity choices to reach your goals. This is the whole idea behind the CICO diet, which stands for Calories In Calories Out.
The logic behind the CICO diet is that once you know your caloric needs, you can add, subtract, or meet them to gain, lose, or maintain weight.
Keep reading for a step-by-step guide to calculating your caloric needs using the Mifflin-St Jeor equation. Plus, you’ll learn how to work with that number once you know it.
Step 1: Calculate Your Basal Metabolic Rate (BMR)
It all starts with the basal metabolic rate (BMR). That’s the number of calories your body burns just to stay alive. Even if you stayed in bed all day, your body would still require energy (aka calories) to breathe, pump blood, produce cells and hormones, and so on.
One of the most reliable ways to calculate BMR is by using the Mifflin-St Jeor equation, which factors in your weight, height, age, and gender.
By plugging your own numbers into this formula, you can get a personalized estimate of how many calories your body burns at rest. I say “estimate” because while this is one of the most accurate ways to calculate your BMR, it’s not a perfect science. (More on this later.)
Let’s take an example and calculate this together. For instance, if you’re a 35-year-old woman who’s 5’4’’ and weighs 165 pounds, you’d first need to calculate your height and weight in centimeters and kilograms.
- Height in centimeters = height in inches x 2.54 or 64 x 2.54 = 162.56
- Weight in kilograms = weight in pounds ÷ 2.2 or 165 ÷ 2.2 = 75
Now, let’s plug these numbers into the BMR equation.
- BMR = (10 × 75) + (6.25 × 162.56) – (5 × 35) – 161
- BMR = 750 + 1016 – 175 – 161
- BMR ≈ 1,430 calories/day
This means your body requires about 1,430 calories each day just to maintain essential functions. However, since you don’t spend all day lying down, you need to adjust your energy needs based on how active you are.
Step 2: Adjust BMR Based on Your Activity Level
Now that you know your BMR, you can factor in your activity level to get a more accurate picture of how many calories you really need each day. That’s your total daily energy expenditure (TDEE). TDEE considers your daily movement and adjusts your caloric needs accordingly. (1) To estimate your TDEE, you can use the following activity level multipliers:
Sedentary (little to no exercise)
Use this activity level multiplier if you get minimal activity or movement throughout the day–say, because you drive to work and have a desk job. (1)
Activity multiplier: BMR × 1.2
Lightly active (exercise 1-3 days per week)
This is when you perform some activity–such as going for a walk–up to three days a week. (1)
Activity multiplier: BMR × 1.375
Moderately active (exercise 3-5 days per week)
Let’s say you walk a lot in your day-to-day life and exercise most days; you’d be considered moderately active. (1)
Activity multiplier: BMR × 1.55
Very active (exercise 6-7 days per week)
If you’re engaging in any purposeful exercise–like hopping on the elliptical –most days, or you have a physical job, you’d be considered very active. (1)
Activity multiplier: BMR × 1.725
Super active (hard exercise or physical job)
You’d be considered super active if you pushed yourself hard when you work out–say in spin class–or if you have an intensely physical job. (1)
Activity multiplier: BMR × 1.9
Getting back to our example, if you exercise four times per week, your activity multiplier would be BMR × 1.55. Your BMR was 1,430 calories, so the equation looks like this.(1)
TDEE = 1,430 × 1.55 = 2,216.50 calories/day
This means that for you to maintain your current weight, you’d need around 2,215 calories per day. Now, we’ll adjust this number based on your goals.
Step 3: Set Your Goal: Weight Loss, Maintenance, or Gain
Here’s where you’ll learn how to calculate your caloric needs depending on your personal goal.
For weight loss:
The logic behind the CICO diet is that a pound is roughly equivalent to 3,500 calories. (6) Therefore, to lose weight, you’d subtract 250 to 500 calories from your TDEE.
Using our example TDEE of 2,215, you can cut your intake by 500 calories, aiming for a daily intake of around 1,715 calories. This should lead to a gradual, sustainable weight loss of about 1 pound per week.
Remember that gradual changes are helpful because they don’t feel overwhelming. Also, keep in mind again that while calorie counting is a helpful tool for weight loss, it isn’t a precise science. You may lose more or less weight than predicted after calculating your personal caloric needs for weight loss.
For weight gain:
If you’re trying to gain muscle or increase your weight, you’ll need to consume more calories than your TDEE. Your caloric needs for weight gain can increase by about 500 calories per day, bringing your total to around 2,715 calories.
A calorie counting tool will come in handy as you focus on adding calories for weight gain.
For maintenance:
For weight maintenance, aim to match your calorie intake to your TDEE. In our example, that would mean consuming about 2,215 calories per day.
Whatever your goal, making small, gradual adjustments is the best way to ensure long-term success. Extreme caloric deficits or surpluses can be difficult to sustain and may negatively impact your health. A calorie counting app, like MyFitnessPal, can help you follow the CICO diet for weight gain, loss, or maintenance.