Your measurements, your units. Use metric, imperial, or both—anytime.
No sign-up • Results update live • Data stays in your browser
Calculator
One system at a time — switch to Both per field to show metric & imperial.
Press Enter to save • R to resetTap Save or Reset above • External keyboard: Enter / R
Result
Healthy BMI range: 58.1 – 78.4 kg • 128 – 173 lb — you are in the middle of the healthy band.
IDEAL WEIGHT
58.1 – 78.4 kg
128 – 173 lb
✓ In healthy range
—
WATER ~
2.5 L / day
85 fl oz / day
35 ml per kg • 0.5 oz per lb
BMR
1,680 kcal/day
At rest (Mifflin-St Jeor)
TDEE — DAILY NEED
2,603 kcal/day
Maintain weight (moderate)
LOSE 0.5kg/wk
2,103 kcal
MAINTAIN
2,603 kcal
GAIN 0.5kg/wk
3,103 kcal
You're in the healthy range — keep it steady.
Focus on 150 min/week moderate activity, protein 1.2–1.6 g/kg, sleep 7–9 h. Small, consistent habits beat crash diets.
No history yet
Calculate and click “Save to history” to track progress over time.
Macro calculator
Synced to your TDEE — all three now move with your calorie goal. Adjust protein, carbs & fat.
Based on 2,603 kcal TDEE (moderate) — all macros scale with this.
Split
2,603 kcal • 100%PROTEIN
130 g
518 kcal • 22%
0.82 g/lb
CARBS
326 g
1,304 kcal • 50%
4 kcal/g
FAT
81 g
729 kcal • 28%
9 kcal/g
Per meal (÷ 3) · fiber guide
Reference
| Category | BMI | Health note |
|---|---|---|
| Underweight | < 18.5 | Possible nutritional deficiency |
| Healthy weight | 18.5 – 24.9 | Lowest risk — aim to stay here |
| Overweight | 25 – 29.9 | Increased risk — lifestyle review helps |
| Obesity | ≥ 30 | Higher risk — consider professional guidance |
BMI is a screening tool, not a diagnosis. It doesn’t directly measure body fat, muscle mass, bone density, or fat distribution. Athletes and older adults should interpret with context.
Understanding your numbers
This BMI Calculator estimates BMI from height and weight and places the result on the BMI chart. BMI does not directly measure body fat, and the BMI categories and ranges for children and teenagers are interpreted differently from adult ranges. Your ideal weight range, estimated BMR and TDEE, calorie needs, macro targets, fiber guidance and daily water intake are calculated together from the same inputs. Use metric, imperial or both per field, and keep results in local history — everything runs in your browser for privacy. All values are estimates to help plan, not medically exact measurements.
BMR is the energy your body uses at rest for basic functions like breathing and organ activity. This BMR calculator uses the Mifflin-St Jeor equation — from age, gender, height and weight — to calculate BMR as an estimate. Use it as a baseline; individual results vary.
BMR is estimated, not medically exact — it builds the foundation for your calorie needs.
TDEE = BMR × activity — your estimated maintenance calories. Higher activity gives higher calorie needs, lower activity gives lower needs.
TDEE is also an estimate; 1.55 is a common middle ground if you are unsure of activity level.
Calorie targets for maintaining, losing or gaining weight build on estimated TDEE — roughly −500 kcal/day for gradual loss or +400 kcal/day for gain. From your chosen target, the macro calculator splits calories into protein, carbs and fat — protein scales with body weight, while carbs and fat share what remains — with fiber guidance around 14 g per 1,000 kcal. Macro targets stay synced with your calorie goal.
Calorie and macro values are estimates. Small, steady adjustments tend to work best.
Daily water intake is estimated from body weight — about 35 ml per kg (0.5 oz per lb). Adjust for heat, exercise and sodium; this is a guide for everyday hydration, not a prescription.
Core formula — how BMI is measured
BMI = weight(kg) ÷ height(m)²
Example: 72 kg ÷ (1.76 m × 1.76 m) = 23.3 — which falls in the healthy BMI range of 18.5–24.9 on the WHO BMI chart. For adults this range is the same across genders; for children and teenagers, BMI is interpreted differently with age- and sex-specific charts. BMI is an estimate, not a direct measure of body fat.