Calculating your calorie needs: BMR, formula and example

Before you count calories, you need a point of reference: your daily calorie needs. They tell you roughly how much energy your body uses on a normal day, and therefore where your maintenance level lies: below it you lose weight, above it you gain. The good news: you can estimate it yourself with a simple formula in two minutes.

Calculate it now: our free calorie calculator uses the same Mifflin-St Jeor formula as the app, shows every step of the calculation and gives you your basal metabolic rate, your maintenance level and a daily target for your goal.

Basal metabolic rate and activity: the difference

Your total energy expenditure is made up of two building blocks:

• Basal metabolic rate (BMR): the energy your body uses at complete rest, for heartbeat, breathing, brain, organ functions and body temperature. For most people it makes up the largest part of daily expenditure and depends mainly on weight, height, age and sex.
• Activity: everything on top of that: walking, working, climbing stairs, sport, even fidgeting and digestion itself. This part varies a lot: between an office day and a day on a building site there can easily be several hundred calories.

Two often overlooked items belong to the activity part: digestion itself (part of the calories you eat is used to process food, more for protein than for fat and carbohydrates) and unconscious everyday movement: fidgeting, standing up, walking around. The latter in particular explains why two people with identical key data can burn different amounts.

BMR plus activity gives your total daily energy expenditure, the number you base your daily target on.

The Mifflin-St Jeor formula

There are several formulas for estimating BMR. For most adults, the Mifflin-St Jeor formula is considered one of the most reliable, which is why it is widely used. myfoody also calculates your calorie target with exactly this formula when you set up the app. It reads:

Men:
BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5

Women:
BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) − 161

Worked example, step by step

Let’s take a woman, 32 years old, weighing 68 kg, 170 cm tall:

• 10 × 68 kg = 680
• 6.25 × 170 cm = 1,062.5
• 5 × 32 years = 160
• 680 + 1,062.5 − 160 − 161 = about 1,420 kcal BMR

She works in an office but walks regularly and trains once or twice a week, an activity factor of about 1.4:

1,420 kcal × 1.4 ≈ 1,990 kcal total expenditure per day.

For comparison, a man, 28 years old, 82 kg, 182 cm: 820 + 1,137.5 − 140 + 5 ≈ 1,820 kcal BMR. With moderate exercise (factor 1.55) he ends up at about 2,820 kcal total expenditure.

Activity factors: honesty pays off

The activity factor (also called PAL value) translates your everyday life into a number. Common guide values:

Factor	Everyday life
1.2	Mostly sitting, hardly any movement (e.g. office + car + sofa)
1.375	Lightly active: some everyday movement, 1–3 easy workouts per week
1.55	Moderately active: regular movement, 3–5 workouts per week
1.725	Very active: physical work or 6–7 workouts per week
1.9	Extremely active: hard physical work plus intense training

The most common mistake at this point: overestimating yourself. Two gym visits a week don’t turn an office job into a “very active” lifestyle. If in doubt, choose the lower factor. You can always correct it upwards if the scales drop too quickly.

From needs to target

Your total expenditure is your maintenance level. Your goal decides how you deviate from it:

• Lose weight: a moderate deficit of about 300–500 kcal below your total expenditure is easy to sustain for most people. Why aggressive deficits usually backfire is explained in Losing weight without hunger.
• Maintain: eat at roughly your total expenditure and watch the trend.
• Build muscle: a small surplus of about 200–300 kcal, combined with strength training, is usually enough.

Why the number is still only a starting value

Every formula estimates the average, but you are not an average person. Metabolism, muscle mass, everyday movement and even how much you fidget unconsciously mean your real expenditure can differ from the calculated value. So:

1. Take the calculated needs as your starting point.
2. Track and weigh yourself consistently for two to three weeks. How that works in practice is shown in Counting calories for beginners.
3. Adjust based on your weight trend: if nothing happens, lower your target by 100–200 kcal; if it goes too fast, raise it accordingly.

And remember to keep the calculation up to date: after a change of several kilos, your needs drop (or rise) too. If progress stalls despite a deficit, you will find the most common causes in the article Breaking through a weight loss plateau.

This article is for general information only and does not replace medical or dietary advice. Formulas provide estimates for healthy adults. During pregnancy or breastfeeding, or with illnesses or eating disorders, please talk to your doctor.

Frequently asked questions about calorie needs

Which formula is the most accurate for calorie needs?

For most people, the Mifflin-St Jeor formula gives a good estimate of basal metabolic rate and is often recommended as the standard. But every formula remains an estimate. Only your weight trend over two to three weeks shows your real needs.

Why am I not losing weight even though I eat below my calculated needs?

Usually it comes down to one of three things: the calculated needs are set too high for you (for example an overestimated activity factor), your actual calorie intake is higher than tracked, or water retention is masking fat loss on the scales. Watch the trend over several weeks before you change anything.

Do I need to recalculate my calorie needs regularly?

Yes, after bigger changes. As a rule of thumb, recalculating is worthwhile after a weight change of about 5 kg or when your daily life changes noticeably (new job, more or less sport). A lighter body uses less energy.

Does exercise count on top of the calculated needs?

If you have already included your exercise in the activity factor, no. Otherwise you count it twice. Either include workouts via the factor or add them individually, but never both.