Harris Benedict Formula - Basal Metabolic Rate Calculator

Find out how much should you be eating for your specific goal!

The Harris Benedict BMR calculator calculates the minimum amount of calories you need to maintain your weight as well as perform your day to day activities based on sex, age, height and weight.

The formula used is the Harris Benedict Formula and is only an approximate estimate but it gives you a starting point. More on this formula later.

First of all please complete the form below to get an approximate BMR figure. (conversion charts are below if you need them). Then continue below for further instructions.

Note : If you are any heavier/lighter than the range given in the 'weight' conversion chart just add/subtract 3.15kg for every half stone or 7lbs over/under you are. For example if you are 14.5 stone (or 203lbs) you'd be 92.15kg.

NOW YOU HAVE YOUR BMR...

You're nearly finished. We just have to look at how active you are in your lifestyle to get a true representation of how many calories you will need to maintain your weight. We'll now find your total daily energy expenditure or your TDEE.

WHAT IS YOUR GOAL?

Important Note : Remember that not all calories are created equal! A 3000 calorie diet consisting of mainly junk food and saturated fats is NOT the same as a 3000 calorie diet consisting of protein, complex carbs and essential fats.

The Harris Benedict Formula is pretty accurate for all but the really muscular physiques (it will underestimate your calorie requirements) and the really overweight (it will overestimate your requirements).

If you find yourself in the latter situation, it would be wise to find out your LBM - Lean body mass. You can do this by getting a body fat check.

Then, take your LBM and add 10% to it. Then put that figure into the calculator for a closer estimate for what your daily calorie needs are.

For example if my LBM was 67kg, I'd add 10% to it. 67 + 6.7 = 73.7kg and I'd put that into the calculator.

Or

If you fancy doing the math all on your own, there is a more accurate formula than the Harris Benedict Formula that takes Lean Body Mass into account. It's called

The Katch-Mcardle Formula

This formula is more accurate for everybody but you'll have to know your LBM first. The formula works for both men and women because no guess work needs to be done with body fat levels once you've obtained your lean body mass.

BMR = 370 + (21.6 X lean body mass in kg)

My Example

I'm 74kg in total weight
I have a body fat % of 12%
So my lean weight is 65.1 kg

My BMR is 370 + 1406 = 1776 calories (very close to what the harris-benedict formula gave me)

Then multiply that figure again depending on your activity level.

So mine would be 1776 calories x 1.375 (lightly active) = 2446 Calories needed to maintain weight

As you can see the difference in results between the Katch Mcardle Formula and the Harris Benedict Formula were negligable for me. If you're between 10-18% bodyfat (higher for women), then the calculator at the top of this page will serve you fine (unless you're extremely muscular).

If not, find out your LBM and use the Katch-Mcardle Formula