Pounds to Kilograms Converter
Convert weight between pounds, kilograms, stone, ounces, and grams. Complete weight unit conversion with all results displayed.
Pounds to Kilograms Converter
Calculator
Adjust values & calculateEnter your values below. Every result is computed in your browser — no data is sent to any server.
Formula: kg = lb x 0.453592 | lb = kg x 2.20462 | 1 stone = 14 lb | 1 lb = 16 oz
Worked example — 185 lb = 83.91 kg = 13 st 3 lb = 2,960 oz
Formula
kg = lb x 0.453592 | lb = kg x 2.20462 | 1 stone = 14 lb | 1 lb = 16 oz
All weight conversions go through a base unit (grams). Pounds to kilograms uses the factor 0.453592 (1 lb = 453.592 g). The stone is 14 pounds. An ounce (avoirdupois) is 1/16 of a pound. Kilograms, the SI base unit for mass, is defined by the International Bureau of Weights and Measures.
Worked Examples
Example 1: Body Weight Conversion
Problem:Convert 185 pounds to kilograms and stone.
Solution:Kilograms: 185 / 2.20462 = 83.91 kg Stone: 185 / 14 = 13 stone 3 pounds Ounces: 185 x 16 = 2,960 oz Grams: 185 x 453.592 = 83,914.5 g
Result:185 lb = 83.91 kg = 13 st 3 lb = 2,960 oz
Example 2: Cooking Measurement
Problem:A recipe calls for 250 grams of flour. How many ounces is that?
Solution:Ounces: 250 / 28.3495 = 8.82 oz Pounds: 250 / 453.592 = 0.5512 lb Approximately 8.8 ounces or just over half a pound.
Result:250 g = 8.82 oz = 0.55 lb
Frequently Asked Questions
How do I convert pounds to kilograms?
To convert pounds to kilograms, divide the weight in pounds by 2.20462 (or multiply by 0.453592). For example, 150 pounds = 150 / 2.20462 = 68.0389 kg. For a quick mental estimate, divide pounds by 2.2 or simply halve the number and subtract 10%. So 150 lbs is roughly 75 - 7.5 = 67.5 kg (actual: 68.04 kg). This conversion is important for international travel, sports, medicine, and cooking.
What is a stone and how does it relate to pounds?
A stone is a unit of weight equal to 14 pounds (6.35 kg), used primarily in the UK and Ireland for measuring body weight. For example, a person weighing 154 pounds weighs 11 stone exactly (154 / 14 = 11). A person weighing 165 pounds weighs 11 stone 11 pounds (165 / 14 = 11 remainder 11). The stone is not commonly used in the US or in scientific contexts, but remains standard in British and Irish everyday language.
What is the difference between mass and weight?
Mass is the amount of matter in an object (measured in kilograms), while weight is the force of gravity on that mass (measured in newtons). On Earth's surface, a 1 kg mass weighs approximately 9.81 newtons. In everyday language and for this converter, 'weight' and 'mass' are used interchangeably since we're always measuring on Earth. The distinction matters in physics and space — your mass stays the same on the Moon, but you'd weigh only about 1/6 as much.
Why are troy ounces different from regular ounces?
A regular (avoirdupois) ounce equals 28.3495 grams and is used for everyday weighing. A troy ounce equals 31.1035 grams and is used exclusively for precious metals (gold, silver, platinum). Confusingly, while a troy ounce is heavier than an avoirdupois ounce, a troy pound (12 troy ounces = 373.24 g) is lighter than an avoirdupois pound (16 ounces = 453.59 g). Pounds to Kilograms Converter uses avoirdupois ounces, the standard for general-purpose weight measurement.
Where does the conversion factor 0.45359237 come from?
It is a definition rather than a measurement. The 1959 International Yard and Pound Agreement fixed the international avoirdupois pound at exactly 0.45359237 kilograms, harmonising slightly different national pound standards. Every derived factor follows from it: the reciprocal 2.20462 pounds per kilogram, 453.592 grams per pound, and 28.3495 grams per ounce as one sixteenth of a pound. The kilogram itself is now defined through a fixed value of the Planck constant.
Why do metric tons, short tons and long tons differ?
The metric ton, or tonne, is 1000 kilograms, which is about 2204.62 pounds. The US short ton is 2000 pounds, roughly 907.185 kilograms, and the imperial long ton is 2240 pounds, about 1016.05 kilograms. Freight quotes, scrap metal prices and shipping capacities can use any of the three, and the spread between short and metric is over 10 percent, so contracts should state which ton applies rather than relying on context.
What do gross weight, tare weight and net weight mean when weighing goods?
Gross weight is everything on the scale, tare weight is the container, pallet or vehicle alone, and net weight is gross minus tare, meaning the product itself. Most digital scales have a tare button that zeroes the display with the empty container in place so subsequent readings are net directly. The distinction drives freight billing and packaging compliance, and it applies identically whether the readout is in pounds, kilograms or grams.
Does a scale reading change with altitude or location?
A balance that compares masses gives the same answer anywhere, but a spring or load cell scale measures force and is therefore sensitive to local gravitational acceleration, which varies by a few tenths of a percent between the equator and the poles and falls slightly with altitude. That is why commercial scales are calibrated on site with certified test masses. The kilogram and pound figures in this converter are mass units, so they do not change with location.
Which unit should I use when a recipe, a shipping label and a lab protocol all differ?
Convert everything to a single base unit before doing arithmetic, which is exactly how this tool works internally by routing all values through grams. Grams suit recipes and lab work because the numbers stay whole and precise; kilograms suit shipping and body weight; pounds and ounces persist in US retail packaging. Mixing units mid calculation, such as adding ounces to grams, is the most common source of error, so normalise first and round only at the end.
Why is the pound abbreviated lb, and should it ever be written lbs?
The abbreviation comes from libra, the Roman unit of weight behind the phrase libra pondo, a pound by weight, which also gives English the word pound. In careful technical writing unit symbols are invariant: 5 lb, not 5 lbs, and 5 kg, never 5 kgs, because a symbol is not an abbreviation of an English word and takes no plural and no full stop. Everyday commercial usage prints lbs freely, but the singular form is what standards documents and scientific style guides expect.
References
Background & Theory
1 kilogram = 2.20462262 pounds, and 1 pound = 0.45359237 kilograms exactly. The second figure is a definition, not a measurement: the 1959 International Yard and Pound Agreement fixed the international avoirdupois pound at exactly 0.45359237 kg, and every other mass factor on this page is derived from it.
Conversion reference table
| Conversion | Equivalent | Exact or rounded? |
|---|---|---|
| 1 pound (avoirdupois) | 0.45359237 kilograms | Exact by definition |
| 1 kilogram | 2.20462262 pounds | Derived, rounded to 9 figures |
| 1 ounce (avoirdupois) | 28.349523125 grams | Exact (1/16 lb) |
| 1 stone | 6.35029318 kilograms | Exact (14 lb) |
| 1 short ton (US) | 907.18474 kilograms | Exact (2,000 lb) |
| 1 long ton (imperial) | 1016.0469088 kilograms | Exact (2,240 lb) |
| 1 tonne (metric ton) | 1,000 kilograms = 2,204.62262 pounds | Exact / derived |
| 1 troy ounce | 31.1034768 grams | Exact (precious metals only) |
Only the derived column is rounded. Because the pound is defined in terms of the kilogram rather than the other way round, kilograms-to-pounds never terminates: 2.20462262184878 continues indefinitely, so pick a precision and stop. For everyday work two decimals is ample, since a bathroom scale resolves no better than about 0.1 kg. The kilogram itself has been defined since 2019 by a fixed numerical value of the Planck constant, which is why no physical prototype is involved in any of these figures.
Reviewed for accuracy by Manoj Kumar, Mathematics Educator · Editorial policy
Related Calculators
🧮Gallons to Pounds Converter
Calculate gallons to pounds converter with inputs, formulas, and instant results.
🧮Inch Poundsto Foot Pounds Converter
Calculate inch poundsto foot pounds converter with inputs, formulas, and instant results.
🧮Weight to Kilograms Converter
Calculate weight to kilograms converter with inputs, formulas, and instant results.
🧮Newtons to Pounds-Force Converter (N, lbf, kgf)
Convert between Newtons, pounds-force, kilogram-force, and dynes.
🧮Ounces to Grams Converter
Convert weight between ounces, grams, pounds, and milligrams.
🧮Nm to Ft-Lb Converter
Convert torque between Newton-meters, foot-pounds, and inch-pounds.