BMR Calculator Pounds and Inches 2026
Quick Take
The Mifflin-St Jeor formula is the gold standard for calculating BMR and works directly with pounds and inches. For men: BMR = 10 × (weight in kg) + 6.25 × (height in cm) − 5 × (age) + 5. For women: same, but −161 instead of +5. To use imperial units directly, convert pounds to kg (÷2.2046) and inches to cm (×2.54).
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain basic biological functions — breathing, blood circulation, organ function, and cellular repair. It is the foundation of every calorie calculation: total daily energy expenditure (TDEE) equals BMR multiplied by an activity factor. Getting your BMR right is the first step toward accurate calorie targeting.
Most BMR calculators default to metric units (kilograms and centimeters), but US users typically think in pounds and inches. Converting between systems is straightforward, and this article shows both how to do the math and provides worked examples for common body types. If you want instant results, the BMR Calculator on VivMetric accepts pounds and inches directly.
The Mifflin-St Jeor Formula: Gold Standard Since 1990
Developed in 1990 by Drs. Mark Mifflin and Stanton Jeor at the University of Nevada, this formula has become the most widely validated BMR equation in nutrition science. It outperformed the older Harris-Benedict formula in multiple validation studies and is now recommended by the Academy of Nutrition and Dietetics, the USDA, and the WHO as the primary BMR estimation equation for healthy adults.
Metric Version (kilograms and centimeters)
Men: BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) + 5
Women: BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) − 161
Imperial Version (pounds and inches)
To use pounds and inches directly, you need to convert the constants. One pound equals 0.4536 kg and one inch equals 2.54 cm. The imperial forms work out to:
Men: BMR = 4.536 × (weight_lb) + 15.875 × (height_in) − 5 × (age) − 161
Women: BMR = 4.536 × (weight_lb) + 15.875 × (height_in) − 5 × (age) − 322
These imperial formulas produce identical results to the metric version after conversion. The conversion of constants works as follows: 10 × 0.4536 = 4.536, and 6.25 × 2.54 = 15.875, making it possible to calculate BMR directly from pounds and inches without unit conversion.
Worked Examples with Pounds and Inches
Let us walk through two examples to show how the formulas work in practice.
Example 1: 35-Year-Old Woman, 160 lb, 5'7" (67 inches)
BMR = (4.536 × 160) + (15.875 × 67) − (5 × 35) − 322
BMR = 725.76 + 1,063.63 − 175 − 322 = 1,292.39 ≈ 1,292 calories
Example 2: 35-Year-Old Man, 180 lb, 5'10" (70 inches)
BMR = (4.536 × 180) + (15.875 × 70) − (5 × 35) − 161
BMR = 816.48 + 1,111.25 − 175 − 161 = 1,591.73 ≈ 1,592 calories
These values align with published BMR reference data. A 160-pound woman at 5'7" should expect a BMR around 1,250–1,350 calories, and a 180-pound man at 5'10" should fall in the 1,550–1,650 range.
Age and Weight: How BMR Changes
BMR is not static. It changes predictably with age and body composition:
| Factor | BMR Effect | Magnitude |
|---|---|---|
| Age (per decade after 25) | ↓ Decreases | −2 to −5% per decade |
| Lean mass (per pound) | ↑ Increases | ~13 kcal/lb lean mass/day |
| Body fat (per pound) | ↑ Slight increase | ~2 kcal/lb fat/day |
| Thyroid function | Variable | −20% to +20% |
The most impactful variable is lean body mass. Muscle tissue is metabolically active — it burns roughly 13 calories per pound per day at rest. Fat tissue is far less metabolically active, burning only about 2 calories per pound per day. This means that two people with identical body weight and height can have significantly different BMR values if their body compositions differ. A 180-pound bodybuilder with 160 pounds of lean mass will have a higher BMR than a 180-pound sedentary person with 130 pounds of lean mass and 50 pounds of fat.
Age affects BMR through sarcopenia — the gradual loss of lean muscle mass that begins in the third decade of life. After age 25, BMR typically declines 2–5% per decade, primarily due to reduced lean mass. This is why caloric needs decrease with age even when body weight remains stable.
Harris-Benedict: The Older Alternative
The Harris-Benedict formula, developed in 1918 and revised in 1984, was the standard BMR equation for nearly 70 years. It is still used by some calculators and clinical tools, though it has been shown to overestimate BMR by 5–10% compared to direct calorimetry in most populations.
Men: BMR = 66.4730 + (13.7516 × weight_kg) + (5.0033 × height_cm) − (6.7550 × age)
Women: BMR = 655.0955 + (9.5633 × weight_kg) + (1.8496 × height_cm) − (4.6756 × age)
A 2021 study in the Journal of the Academy of Nutrition and Dietetics compared the two formulas in a cohort of 400 US adults and found that Mifflin-St Jeor was within 5% of measured BMR (via indirect calorimetry) in 78% of participants, while Harris-Benedict was within 5% in only 56%. For this reason, the Mifflin-St Jeor equation is preferred for individual use, though Harris-Benedict can still serve as a rough estimate when historical comparison data is needed.
Validating Your BMR with Real-World Data
The Mifflin-St Jeor formula provides an estimate — not a direct measurement. Several factors can cause your actual BMR to differ from the calculated value:
| Factor | BMR Deviation | Population Affected |
|---|---|---|
| Untrained vs Resistance-Trained | +5 to +15% | Strength athletes |
| Hypothyroidism | −10 to −20% | Untreated thyroid conditions |
| Hyperthyroidism | +10 to +20% | Untreated thyroid conditions |
| Rapid weight loss | −5 to −15% | Individuals in active deficit |
| Altitude (>10,000 ft) | +5 to +10% | High-altitude residents |
If you have a thyroid condition, are taking medications that affect metabolism (such as thyroid hormone replacement or beta-blockers), or have recently lost significant weight, the Mifflin-St Jeor formula may need adjustment. In those cases, indirect calorimetry (metabolic testing) is the most reliable measurement method, though it typically requires a clinical setting.
Using the BMR Calculator on VivMetric
The BMR Calculator on VivMetric uses the Mifflin-St Jeor equation with support for both imperial (pounds, inches) and metric (kilograms, centimeters) inputs. It also provides an adjusted BMR based on body composition estimates when you input additional data. Combined with the TDEE Calculator, you can move from resting metabolism to total daily energy expenditure in seconds.
For users looking to understand their lean mass vs fat mass contribution to BMR, the Body Fat Calculator and Lean Body Mass Calculator provide additional context. And if you are working toward a specific calorie target, the Calorie Deficit Calculator shows how different BMR and activity combinations translate to deficit numbers.