Pounds to Kilograms
Convert pounds to kilograms for medical dosing, international travel, and metric fitness records. 1 lb = 0.453592 kg — enter any pound value for instant conversion.
Enter your values above to see the results.
Tips & Notes
- ✓Quick approximation: divide lbs by 2.2. Example: 150 lbs ÷ 2.2 = 68.18 kg (exact: 68.04 kg). Accurate to within 0.21% for everyday use.
- ✓Medical dosing: many drugs are dosed in mg/kg. A 160 lb patient = 72.57 kg. A drug at 5 mg/kg dose = 72.57 × 5 = 362.9 mg. Always convert to kg for medication calculations — using pounds directly in mg/kg formulas causes dangerous overdosing.
- ✓BMI calculation uses kg and meters: BMI = weight(kg) / height(m)². A 180 lb person 5 ft 10 in tall: weight = 81.65 kg, height = 1.778 m, BMI = 81.65 / (1.778²) = 81.65 / 3.161 = 25.8 (slightly overweight by WHO standards).
- ✓International gym equipment: most non-US gyms use kg plates. A 45-lb plate = 20.41 kg. A loaded bar of 135 lbs = 61.23 kg; 225 lbs = 102.06 kg; 315 lbs = 142.88 kg; 405 lbs = 183.70 kg.
- ✓Stone to kg: 1 stone = 14 lbs = 6.350 kg. Common in UK body weight reporting. To convert stone to kg: multiply stone by 6.350, add any remaining pounds × 0.453592. Example: 11 stone 7 lbs = (11 × 14 + 7) × 0.453592 = 161 × 0.453592 = 73.03 kg.
Common Mistakes
- ✗Dividing by 2 instead of 2.205 — pounds ÷ 2 = half the weight in lbs, not kg. The correct divisor is 2.20462. Using 2 overstates kg by 10.2%, leading to significant medical dosing errors.
- ✗Using lbs directly in mg/kg drug dosing formulas — all clinical dosing is in mg/kg (kilograms). A 200-lb patient is 90.72 kg, not 200 kg. Confusing lbs with kg in dosing calculations is a recognized medication error type.
- ✗Forgetting the difference between net weight and gross weight for shipping — international shipping invoices list gross weight (package + contents) in kg. Tare weight (empty packaging) must be subtracted for customs declarations of net product weight.
- ✗Applying the pounds-to-kg factor to pounds-force — in engineering, pound-force (lbf) converts to newtons (N), not kg. 1 lbf = 4.448 N = 0.453592 kg-force (kgf) at standard gravity. These are force units, not mass units.
- ✗Confusing troy pounds and avoirdupois pounds for precious metals — gold and silver are measured in troy ounces and troy pounds. 1 troy pound = 12 troy oz = 373.242 g = 0.373242 kg. 1 avoirdupois pound = 16 oz = 453.592 g. If pricing gold in pounds, always verify which pound type is used.
Pounds to Kilograms Overview
Pounds are the US standard for everyday weight — body weight, food quantities, gym equipment, and shipping rates. Converting to kilograms is essential for medical dosing, international travel, metric-based fitness tracking, and understanding global product specifications.
Pounds to kilograms formula:
kg = lbs × 0.453592 | Quick: kg ≈ lbs ÷ 2.205 | 1 lb = 0.45359237 kg (exact definition)
EX: Body weight 165 lbs → 165 × 0.453592 = 74.84 kg. Airline bag 50 lbs limit → 50 × 0.453592 = 22.68 kg. Drug dose 5 mg/kg for 74.84 kg = 374.2 mg total doseInverse — kg to lbs:
lbs = kg × 2.20462 | 1 kg = 2.20462 lbs
EX: Verify: 74.84 kg × 2.20462 = 164.99 lbs ≈ 165 lbs ✓. Metric dumbbell 20 kg → 20 × 2.20462 = 44.09 lbsBody weight conversions — lbs to kg:
| Pounds (lbs) | Kilograms (kg) | BMI at 5 ft 9 in (1.75 m) |
|---|---|---|
| 110 lbs | 49.90 kg | 16.3 (underweight) |
| 130 lbs | 58.97 kg | 19.2 (normal) |
| 150 lbs | 68.04 kg | 22.2 (normal) |
| 170 lbs | 77.11 kg | 25.1 (overweight) |
| 190 lbs | 86.18 kg | 28.1 (overweight) |
| 210 lbs | 95.25 kg | 31.1 (obese class I) |
| 230 lbs | 104.33 kg | 34.0 (obese class II) |
| Equipment | Pounds (lbs) | Kilograms (kg) |
|---|---|---|
| Standard Olympic plate (large) | 45 lbs | 20.41 kg |
| Olympic barbell (men) | 45 lbs | 20.41 kg |
| Loaded bar (beginner) | 135 lbs | 61.23 kg |
| Loaded bar (intermediate) | 225 lbs | 102.06 kg |
| Loaded bar (advanced) | 315 lbs | 142.88 kg |
| Loaded bar (elite) | 405 lbs | 183.70 kg |
Frequently Asked Questions
Multiply lbs by 0.453592. Examples: 1 lb = 0.454 kg; 10 lbs = 4.536 kg; 50 lbs = 22.680 kg; 100 lbs = 45.359 kg; 150 lbs = 68.039 kg; 200 lbs = 90.718 kg. Quick method: divide lbs by 2.205 (or 2.2 for rough estimates). Example: 165 lbs ÷ 2.205 = 74.83 kg. Exact: 165 × 0.453592 = 74.84 kg.
Most medications and clinical calculations use kg-based dosing. Pediatric doses are almost always in mg/kg or mcg/kg. Adult medications like chemotherapy, anticoagulants, and antibiotics are also weight-based. Formula: dose (mg) = dose rate (mg/kg) × body weight (kg). A 165-lb (74.84 kg) patient prescribed amoxicillin at 25 mg/kg/day gets 74.84 × 25 = 1,871 mg/day. Using 165 (lbs) instead of 74.84 (kg) would give 4,125 mg — a dangerous 2.2× overdose. Always confirm weight in kg with your healthcare provider.
Standard BMI formula uses kg and meters: BMI = weight(kg) / height(m)². Convert lbs to kg first (divide by 2.205), and height from inches to meters (multiply by 0.0254). Example: 175 lbs, 5 ft 9 in (= 69 inches). Weight: 175 / 2.205 = 79.37 kg. Height: 69 × 0.0254 = 1.7526 m. BMI = 79.37 / (1.7526²) = 79.37 / 3.072 = 25.84 (slightly above normal range of 18.5-24.9). Alternative using US-unit formula: BMI = (weight in lbs × 703) / height² in inches = (175 × 703) / 69² = 123,025 / 4,761 = 25.84.
Powerlifting milestone conversions: 135 lbs (3-plate bench warm-up) = 61.23 kg; 225 lbs (standard challenge) = 102.06 kg; 315 lbs = 142.88 kg; 405 lbs = 183.70 kg; 500 lbs (half-ton) = 226.80 kg. Olympic plates: 45-lb plate = 20.41 kg; 35-lb plate = 15.88 kg; 25-lb plate = 11.34 kg; 10-lb plate = 4.54 kg; 5-lb plate = 2.27 kg. Barbells: 45-lb Olympic bar = 20.41 kg; 35-lb women bar = 15.88 kg. Bodyweight benchmarks: squat 1× bodyweight (150 lbs = 68.04 kg) to 2× bodyweight (300 lbs = 136.08 kg).
US food labeling law (FDA): net weight must be declared in both US customary (oz or lbs) and metric (g or kg) on packaged food sold in the US. European food sold in the US must therefore show both systems. Common food package weights: 1 lb (16 oz) bag = 453.6 g; 2-lb bag = 907.2 g; 5-lb bag = 2.268 kg. For cooking: 1 cup of all-purpose flour weighs about 120 g = 0.265 lbs = 4.23 oz. A pound of butter = 453.6 g = 2 cups US. Recipes converting from US (cups, lbs) to metric (grams, ml) require both volume-to-weight and lbs-to-grams conversions.
Aviation weight limits bridge both systems. US domestic airlines quote baggage limits in lbs; international carriers often use kg. Conversions: checked bag economy limit 50 lbs = 22.68 kg; business class 70 lbs = 31.75 kg; overweight fee threshold 50-70 lbs (22.68-31.75 kg). Carry-on: typically 22-40 lbs = 9.98-18.14 kg depending on airline. Personal item: usually 15-25 lbs = 6.80-11.34 kg. General aviation (private aircraft): payload limits critical — a 400 lb passenger + luggage limit = 181.44 kg. Exceeding limits is a safety issue; always convert precisely for aviation weight calculations.