Basal Metabolic Rate (BMR)
— kcal/day
Energy your body uses each day at complete rest.
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Calorie Calculator
Wondering, “How many calories do I need per day?” This daily calorie needs calculator estimates your basal metabolic rate (BMR), total daily energy expenditure (TDEE), and maintenance calories with the Mifflin–St Jeor formula. Designed as a BMR calculator for men and women and a TDEE calculator with activity levels, it supports metric and imperial measurements and processes every value privately in your browser.
How This Calorie Maintenance Calculator Works
Formula, activity levels, ranges, and limitations
The Mifflin–St Jeor formula
The calculator estimates BMR as 10 × weight (kg) + 6.25 × height (cm) − 5 × age, then adds 5 for males or subtracts 161 for females. This is why the tool functions as a BMR calculator for men and women while using the same underlying equation.
Why activity level matters
BMR covers rest only. Multiplying it by an activity factor estimates TDEE—the energy used through everyday movement, exercise, and digestion.
- Sedentary (1.2): office or desk job with little structured exercise.
- Lightly active (1.375): mostly seated work plus exercise 1–3 days per week.
- Moderately active (1.55): an active job or moderate exercise 3–5 days per week.
- Very active (1.725): construction, delivery, or another physical job, or hard exercise 6–7 days per week.
- Extra active (1.9): strenuous labor, twice-daily training, or a competitive athlete routine.
Typical calorie ranges
Many adults fall around 1,600–3,000 calories per day, but body size, age, activity, health, and goals can move individual needs outside that range.
Editorial and evidence review:
Formula details were checked against the original peer-reviewed
Mifflin–St Jeor research publication.
Last evidence review: July 23, 2026. This page has not been medically reviewed
and does not replace advice from a qualified health professional.
Calorie Calculator FAQ
What is BMR?
Basal metabolic rate, or BMR, estimates how many calories your body uses in a day at complete rest to support essential functions such as breathing, circulation, and temperature regulation.
What is TDEE?
Total daily energy expenditure, or TDEE, is an estimate of the calories you use each day after your BMR is adjusted for everyday movement, exercise, and digestion.
How accurate is the Mifflin–St Jeor formula?
The Mifflin–St Jeor equation is a research-based estimate, not a direct measurement. Actual calorie needs can differ because of body composition, health, medications, training, and other individual factors.
How many calories do I need per day?
Your estimated daily calorie need is the TDEE result. It combines your BMR with the activity level that best represents your typical work, movement, and weekly exercise.
Does activity level affect calorie needs?
Yes. More movement and exercise generally increase daily energy use, so the calculator applies an activity multiplier from 1.2 for sedentary routines to 1.9 for exceptionally active routines.
Important: This calculator is for general informational and
planning purposes only, not medical advice. Avoid aggressive calorie restriction
and consult a qualified health professional for personalized guidance, especially
if you are pregnant, under 18, have a medical condition, take medication that
affects weight or metabolism, or have a history of disordered eating.