BMR Calculator

For anyone who knows me, knows that I am passionate about health. I was speaking to Gunjan about how should we reliably know how much we should eat, in order to better track our health. So I thought I’d create a BMR calculator using some scientifically validated equations, and embed this on my website. This was also a fun thing to do, as I have 0 knowledge about how to code anything, let alone this calculator on a website. So with reliable AI tools, I was able to create this accurate BMR calculator. Context on what it is, and how you can use this in your life is outlined below:

Weight loss or gain is all about calorie deficit or surplus governed by the simple equation: Calories In (Eating) - Calories out (BMR + Activity). If calories In > Calories out, it is a surplus, and you will gain weight. If Calories in < calories out, it is a deficit and you will lose weight. Any diet or exercise regime, no matter how fancy, aims to create this balance. By decreasing calories in through a controlled nutritious diet, and increasing the activity by exercise and activity there is a calorific deficit that is created which leads to weight loss.

There are 4 components of Total Daily Calorie Expenditure:

1. BMR (Basal Metabolic Rate) or RMR (Resting Metabolic Rate): denotes the calories the body requires at rest. This includes the energy needed for body functions at rest to maintain essential life-sustaining functions such as breathing, heartbeat, and brain function. This is 70%-80% of TDEE. This is the majority of the daily calorie expenditure.
2. Non Exercise Activity Thermogenesis: This denotes the calories burnt while doing daily activities and movements that are not qualified as “exercise” like chores, walking, etc. This could range anywhere between 15% depending on activity level. Most of us live sedentary lifestyles and are pretty low here.
3. Exercise Activity Thermogenesis: This is energy required for planned exercise activity like gym, running, sport etc. This counts for anywhere between 5-10%
4. Thermic effect of Food: This is the energy needed by the body to perform digestion and absorb food. This is minimal and possibly accounts for 8-15%.

In order to determine how many calories should one eat - The Mifflin St. Jeor Equation is one of the best approximations that exist today to calculate BMR - the Basal Metabolic Rate. Use the calculator below to estimate your BMR to give you an indicator of how much calories you require in a day.

Once you have this number you can use a factor to calculate TDEE (total daily energy expenditure) - this has been generally validated. Obviously, this is an approximation, over the approximation of the BMR calculation. So take it with a fair bit of expected variance.

Very likely, given you are person who goes to office, and maybe goes to the gym every couple of days, your factor still should be around 1.2 - for the most reasonable estimation.

• Sedentary (little or no exercise): calories = BMR × 1.2;
• Lightly active (light exercise/sports 1-3 days/week): calories = BMR × 1.375;
• Moderately active (moderate exercise/sports 3-5 days/week): calories = BMR × 1.55;
• Very active (hard exercise/sports 6-7 days a week): calories = BMR × 1.725
• Extra active (very hard exercise/sports & a physical job): calories = BMR × 1.9; and
• If you train as a professional athlete: calories = BMR × 2.3