HEALTH / ENERGY
Calorie Calculator
Estimate adult BMR, maintenance calories, and a goal-based daily target from a few body measurements and an activity level.
Set calorie inputs
Use metric units and choose the activity level that best matches a typical week.
Daily calorie estimate
Your calorie estimate will appear here
Enter adult body data and activity level, then calculate.
How this calorie estimate works
The script calculates BMR with Mifflin-St Jeor, multiplies it by an activity factor for maintenance calories, then applies a fixed goal adjustment. It also shows protein and water planning values from body weight.
What the result means
BMR is an estimate of resting energy use. Maintenance calories are a planning estimate for your selected activity level, not a measurement of metabolism.
Where to be careful
The model does not account for medical conditions, pregnancy, medications, changing activity, eating disorders, or individual nutrition needs. Do not treat the 1,200 kcal floor as a personal target.
Frequently Asked Questions
What does this calorie calculator estimate?
It estimates basal metabolic rate, maintenance calories, and a daily calorie target for an adult using the Mifflin-St Jeor equation, an activity multiplier, and a selected goal adjustment.
Which formula does it use?
The calculator uses the Mifflin-St Jeor equation for BMR, then multiplies BMR by the selected activity factor to estimate maintenance calories.
What does the goal change?
Maintain adds 0 calories, mild loss subtracts 300, weight loss subtracts 500, mild gain adds 250, and weight gain adds 400 in this simplified model.
Is this a medical or diet prescription?
No. It is a general adult planning estimate, not medical advice, a diagnosis, or a personalized nutrition prescription.
Where can I compare the estimate with a fuller tool?
The NIH Body Weight Planner provides a separate planning experience with additional inputs and goal timelines.