Pounds to Kilograms Converter
Enter a value in either field, use the slider to explore, or pick a common weight preset.
That Weighs About...
Real-world objects for comparison. The closest match is highlighted.
Quick Reference Table
Common pound values and their kilogram equivalents. The row closest to your input is highlighted.
| Pounds (lb) | Kilograms (kg) | Context |
|---|
Conversion Formulas
kg = lb × 0.45359237
lb = kg × 2.20462262
Quick Estimation
For a fast mental estimate, divide pounds by 2.2 to get kilograms, or multiply kilograms by 2.2 to get pounds. This is accurate within about 0.2%.
About Pounds and Kilograms
The pound (lb) is a unit of mass in the imperial and US customary systems. The abbreviation "lb" comes from the Latin libra, a Roman unit of weight.
The kilogram (kg) is the base unit of mass in the International System of Units (SI). Since 2019, the kilogram is defined by fixing the Planck constant at exactly 6.62607015 × 10²³&sup4; J·s.
In 1959, the US, UK, Canada, Australia, New Zealand, and South Africa agreed to define the international avoirdupois pound as exactly 0.45359237 kilograms.
Common Conversion Scenarios
- Body weight: US medical records use pounds; most other countries use kilograms
- Airline luggage: US airlines list limits in pounds; international flights use kilograms
- Cooking: US recipes use pounds and ounces; metric recipes use grams and kilograms
- Gym and fitness: US gyms label weights in pounds; many other countries use kilograms
- Shipping: international shipping typically requires weights in kilograms
Frequently Asked Questions
How many kilograms are in one pound?
One pound equals exactly 0.45359237 kilograms. This is the internationally agreed conversion factor defined by the international avoirdupois pound standard (1959).
How many pounds are in one kilogram?
One kilogram equals approximately 2.20462 pounds (precisely 1 ÷ 0.45359237 ≈ 2.2046226218 lb).
How do I convert pounds to kilograms?
Multiply the number of pounds by 0.45359237. For a quick estimate, divide by 2.2. Example: 150 lb × 0.45359237 = 68.039 kg.
How do I convert kilograms to pounds?
Multiply the number of kilograms by 2.20462. For a quick estimate, multiply by 2.2. Example: 70 kg × 2.20462 = 154.324 lb.
What is the difference between a pound and a kilogram?
A pound (lb) is a unit of mass in the imperial and US customary systems. A kilogram (kg) is the base unit of mass in the metric system (SI). One kilogram is about 2.2 times heavier than one pound.
Why is the conversion factor 0.45359237?
In 1959, six English-speaking nations agreed to define the international avoirdupois pound as exactly 0.45359237 kilograms.
Is dividing by 2.2 accurate enough?
Yes, for everyday purposes. The result is within about 0.2% of the exact value. Use the exact factor for science or trade.
What is 200 pounds in kilograms?
200 pounds equals approximately 90.72 kilograms (200 × 0.45359237 = 90.718474 kg).
What is 100 kg in pounds?
100 kilograms equals approximately 220.46 pounds (100 × 2.20462 = 220.462 lb).
Do any countries still use pounds?
The United States uses pounds as its primary unit of weight. The United Kingdom uses pounds informally for body weight and some goods, though kilograms are the official standard.
Privacy & Limitations
- All calculations run entirely in your browser -- nothing is sent to any server.
- Results are estimates and may vary based on actual conditions.
Related Tools
- Weight & Mass Converter -- Convert between metric and imperial weight units
- Kilograms to Pounds -- Convert kilograms to pounds and back
- Ounces to Grams Converter -- Convert between ounces and grams
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This tool FAQ
How many kilograms are in one pound?
One pound equals exactly 0.45359237 kilograms. This is the internationally agreed conversion factor defined by the international avoirdupois pound.
How many pounds are in one kilogram?
One kilogram equals approximately 2.20462 pounds (precisely 1 / 0.45359237 ≈ 2.2046226218 lb).
How do I convert pounds to kilograms?
Multiply the number of pounds by 0.45359237. For a quick estimate, divide the pounds by 2.2. Example: 150 lb × 0.45359237 = 68.038856 kg.
How do I convert kilograms to pounds?
Multiply the number of kilograms by 2.20462. For a quick estimate, multiply the kilograms by 2.2. Example: 70 kg × 2.20462 = 154.324 lb.
What is the difference between a pound and a kilogram?
A pound (lb) is a unit of mass in the imperial and US customary systems. A kilogram (kg) is the base unit of mass in the metric system (SI). One kilogram is about 2.2 times heavier than one pound.
Why is the conversion factor 0.45359237?
In 1959, six English-speaking nations agreed to define the international avoirdupois pound as exactly 0.45359237 kilograms. This standard ensures consistent conversions worldwide.
Is the quick rule of dividing by 2.2 accurate enough?
Dividing by 2.2 gives results within about 0.2% of the exact value. For everyday use (cooking, gym, luggage) this is accurate enough. For science, engineering, or trade, use the exact factor 0.45359237.
What is 200 pounds in kilograms?
200 pounds equals approximately 90.72 kilograms (200 × 0.45359237 = 90.718474 kg).
What is 100 kg in pounds?
100 kilograms equals approximately 220.46 pounds (100 × 2.20462 = 220.462 lb).
Do any countries still use pounds?
The United States uses pounds as its primary unit of weight. The United Kingdom uses pounds informally for body weight and some goods, although kilograms are the official standard. Liberia and Myanmar also use non-metric systems in some contexts.