Find out how many calories your body burns at rest from your weight in kg, height in cm, age and sex. The tool uses the Mifflin-St Jeor equation, then applies your activity level to estimate daily maintenance calories (TDEE).
BMR is the energy your body uses at rest; TDEE adds your activity. These are estimates – for personal nutrition guidance, talk to a doctor or registered dietitian.
How to Calculate BMR for a Female in kg
Multiply weight in kg by 10, add 6.25 × height in cm, subtract 5 × age, then subtract 161. A 35-year-old woman at 65 kg and 165 cm gets 650 + 1,031.25 − 175 − 161 = about 1,345 calories a day at rest. Treat it as an estimate, not medical advice.
- Weight: 10 × 65 kg = 650.
- Height: 6.25 × 165 cm = 1,031.25.
- Age: 5 × 35 = 175, so 650 + 1,031.25 − 175 = 1,506.25.
- Subtract 161 for women: 1,506.25 − 161 = 1,345.25 kcal.
To calculate BMR for a male, add 5 at the last step instead. A 30-year-old man at 70 kg and 175 cm gets 700 + 1,093.75 − 150 + 5 = about 1,649 calories.
The Mifflin-St Jeor Equation With Activity Factor
BMR comes from the equation, and your activity factor then scales it up to TDEE. BMR is the calories your body burns at rest just to keep your organs and systems running, so it is not everything you burn in a day.
Formula: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5 for men, or − 161 for women. TDEE = BMR × activity factor, where the factor ranges from 1.2 (sedentary) to 1.9 (very active). Imperial inputs are converted to kg and cm before the formula runs.
- Sex: male or female, since the equation’s constant term differs by sex
- Age: your age in years
- Height: your height in centimeters, or feet and inches in imperial mode
- Weight: your body weight in kilograms, or pounds in imperial mode
- Activity level: sedentary (1.2), light (1.375), moderate (1.55), active (1.725) or very active (1.9), used to scale BMR up to TDEE
BMR vs TDEE: Example Results
The difference is activity. The same woman with a 1,345 kcal BMR and light activity (1.375) has a TDEE of about 1,850 kcal.
| Sex | Age | Height (cm) | Weight (kg) | Activity | BMR / TDEE |
|---|---|---|---|---|---|
| Male | 30 | 175 | 70 | Moderate (1.55) | 1649 / 2556 cal/day |
| Female | 25 | 160 | 55 | Sedentary (1.2) | 1264 / 1517 cal/day |
| Male | 45 | 180 | 85 | Active (1.725) | 1755 / 3027 cal/day |
| Female | 35 | 165 | 65 | Light (1.375) | 1345 / 1850 cal/day |
| Male | 50 | 170 | 78 | Very active (1.9) | 1598 / 3035 cal/day |
| Female | 60 | 155 | 60 | Moderate (1.55) | 1108 / 1717 cal/day |
Using Your Result Wisely
Use it as a starting estimate. It predicts the energy your body uses at complete rest from weight, height, age and sex, and while Mifflin-St Jeor is among the more accurate equations for most adults, individuals can still land well above or below it.
- Don’t treat BMR as a diet target. It covers basic body functions only, so eating below it routinely is rarely a good plan.
- Be honest about activity. Picking a higher activity level than you really have is a common way the maintenance figure ends up too high.
- Very muscular people often burn more than predicted, because the equation knows nothing about body composition.
Eat at the suggested maintenance level for two or three weeks, track your weight trend, and adjust by a small amount if it moves. Recalculate after a significant weight change.
Pregnancy, thyroid disorders and some medicines change metabolism, so a BMR calculator is less useful there; ask a doctor or dietitian. The basal metabolic rate article on Wikipedia compares the other equations in use.
Common questions about BMR
How do you calculate BMR for a female in kg?
Use Mifflin-St Jeor: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161. A 35-year-old woman at 65 kg and 165 cm gets 650 + 1,031.25 − 175 − 161 = about 1,345 calories a day.How do you calculate BMR for a male?
Same equation, but add 5 instead of subtracting 161. A 30-year-old man at 70 kg and 175 cm gets 700 + 1,093.75 − 150 + 5 = about 1,649 calories a day.Is BMR how many calories you burn at rest?
Yes. BMR is the calories your body burns at complete rest, just to stay alive. It does not include walking, exercise or digesting food, so the calories you burn in a full day are higher.What’s the difference between BMR and TDEE?
BMR is your resting burn. TDEE takes that number and multiplies it by an activity factor to estimate the total calories you burn in a full day, including movement and exercise.Should I eat exactly at my BMR to lose weight?
No. BMR alone doesn’t account for daily activity. Eating at or below BMR for extended periods isn’t a general recommendation; most people reference TDEE, which includes activity, when thinking about calorie targets for weight goals.How accurate is BMR estimated from a formula versus measured directly?
Formula-based BMR is an estimate, not a lab measurement. Mifflin-St Jeor is considered one of the more accurate predictive equations for the general population, but individual metabolism can still vary from what any formula predicts.Related Calculators
Once you know your TDEE, the TDEE calculator can help you fine-tune it for cutting or bulking goals, and the calorie calculator can translate that number into a daily calorie target. For a full nutrition breakdown, the macro calculator splits your calories into protein, carbs, and fat.