Calculator Inputs
Example Data Table
Use this to sanity-check your inputs and outputs.
| Sex | Age | Height | Weight | Activity | BMR | TDEE |
|---|---|---|---|---|---|---|
| Male | 30 | 180 cm | 80 kg | 1.55 | ~1780 | ~2750 |
| Female | 28 | 165 cm | 62 kg | 1.375 | ~1370 | ~1885 |
| Male | 40 | 172 cm | 95 kg | 1.2 | ~1805 | ~2165 |
Formula Used
The Mifflin St Jeor equation estimates basal metabolic rate (BMR) in kilocalories per day. It uses weight in kilograms, height in centimeters, and age in years.
- Men: BMR = 10×W + 6.25×H − 5×A + 5
- Women: BMR = 10×W + 6.25×H − 5×A − 161
Total daily energy expenditure (TDEE) is computed as TDEE = BMR × activity factor. Target calories apply your adjustment or a sensible goal default.
How to Use This Calculator
- Enter sex, age, height, and weight using your preferred units.
- Select an activity level that matches your typical week.
- Choose a goal, then optionally set a calorie adjustment.
- Set protein (g/kg) and fat (%) to shape your macro targets.
- Press Calculate to view results above the form.
- Use Download CSV or Download PDF to save outputs.
Notes for Better Accuracy
- BMR is an estimate; real needs vary by body composition and genetics.
- Use weekly averages of weight and intake to judge progress.
- Adjust calories by 100–200 kcal/day if progress stalls for 2–3 weeks.
- Consult a clinician for pregnancy, illness, or eating disorder concerns.
Practical Guidance
Why this equation is widely used
The Mifflin St Jeor method estimates basal metabolic rate from weight, height, age, and sex. Many practitioners prefer it because it often aligns well with measured resting energy in general populations. Treat the number as a baseline, not a promise. Your true needs still shift with sleep, stress, training, and body composition. Use it, then validate with real outcomes weekly.
Interpreting activity factors accurately
Activity multipliers translate BMR into total daily energy expenditure. Sedentary fits mostly seated days. Light suits regular walking with a few workouts. Moderate matches structured training three to five days weekly. Very active covers hard training most days. Extra active is for demanding physical jobs plus training. Pick what reflects your usual month, not a rare week.
Setting a realistic calorie target
For fat loss, a 300–500 kcal daily deficit is a common starting point. For muscle gain, a 200–350 kcal surplus often improves adherence while limiting excess fat. This calculator applies your adjustment or sensible goal defaults. Review progress using 14-day weight trends and gym performance. If change is slow, adjust by 100–200 kcal and reassess.
Macro targets that support performance
Protein is set per kilogram to support lean mass and recovery. Many active adults do well near 1.6–2.2 g/kg. Fat percentage influences satiety and meal flexibility; 20–35% of calories works for many. After protein and fat are set, remaining calories become carbohydrates, which can help training intensity and fiber when sourced from minimally processed foods.
Tracking data and improving accuracy
Accuracy depends on honest inputs and consistent measurement. A misjudged activity level can shift TDEE by several hundred calories. Weigh at similar times, then use weekly averages to reduce noise from water and glycogen changes. Recalculate after meaningful weight changes so protein grams scale correctly. Exporting CSV or PDF supports coaching notes, comparisons, and audit trails.
When professional input matters
Seek clinical guidance for pregnancy, adolescence, chronic disease, or a history of disordered eating. Athletes with weight-class timelines should plan around competitions and recovery phases. If you notice persistent fatigue, sleep disruption, or heightened hunger, prioritize sustainability: increase calories slightly, raise produce and protein, and reduce training stress temporarily. Used thoughtfully, the calculator supports safer, data-driven nutrition decisions.
FAQs
1) What is the difference between BMR and TDEE?
BMR estimates calories burned at rest. TDEE multiplies BMR by an activity factor to approximate total daily calories, including movement, training, and routine living.
2) Which activity level should I choose if my week varies?
Pick the level that matches most weeks across a month. If you have two hard training weeks and two easy weeks, choose moderate and adjust calories using trend results.
3) Why does the calculator set a minimum target calories value?
Very low targets can be unsafe and hard to sustain. A practical floor helps avoid extreme deficits that increase fatigue, poor recovery, and inconsistent adherence.
4) Can I use pounds and feet/inches?
Yes. Select the unit options, enter your values, and the calculator converts them internally to kilograms and centimeters for the equation.
5) How often should I update my calorie target?
Reassess every 2–3 weeks using average weight and performance. If change is too fast or too slow, adjust by 100–200 kcal/day and retest.
6) Are macro targets mandatory for results?
No. They are planning aids. Calories drive weight change, while macros help you distribute calories in a way that supports training, satiety, and food quality.