Weight Converter
Convert between kilograms, pounds, ounces, grams, stone, and other weight units quickly and accurately.
Common Conversions
Related Calculators
What is Weight Converter?
A weight converter is a practical measurement tool that converts between different units of weight and mass used around the world. While the terms "weight" and "mass" are technically different in physics (mass measures the amount of matter, while weight measures gravitational force), they are used interchangeably in everyday life. The two primary systems for measuring weight are the metric system, which uses kilograms and grams, and the imperial system, which uses pounds and ounces. A third traditional unit, the stone (equal to 14 pounds), remains popular in the United Kingdom and Ireland for measuring body weight.
The kilogram is the base unit of mass in the International System of Units (SI). Originally defined in 1795 as the mass of one liter of water at its freezing point, the kilogram was later redefined using a physical artifact, the International Prototype of the Kilogram (a platinum-iridium cylinder stored in France). In 2019, the kilogram was fundamentally redefined based on the Planck constant, a quantum mechanical value that is exact and unchanging. The pound, meanwhile, traces its origins to the Roman libra and was standardized in 1959 as exactly 0.45359237 kilograms through an international agreement between English-speaking nations.
Weight conversion is essential in numerous daily and professional contexts. In fitness and healthcare, body weight is recorded in kilograms, pounds, or stone depending on the country and medical system. Cooking recipes from different regions require conversion between grams, ounces, pounds, and cups. International shipping and logistics depend on accurate weight conversion for freight costs, customs declarations, and vehicle load limits. Grocery shopping, nutritional tracking, postal services, and industrial manufacturing all require fluency in multiple weight units. Our converter handles all these scenarios, supporting kilograms, grams, milligrams, pounds, ounces, stone, and metric tons.
How to Use This Calculator
Using the weight converter is simple and intuitive. Enter the weight value you want to convert and select the source unit from the dropdown menu. The converter instantly calculates and displays equivalent values in all supported weight units, including kilograms, grams, milligrams, pounds, ounces, stone, and metric tons. Results are displayed with appropriate decimal precision for each unit.
For cooking conversions, you can enter weights in grams or ounces to see the equivalent in the other system. For body weight, enter your weight in kilograms, pounds, or stone to see all three conversions simultaneously. For shipping and logistics, the converter handles everything from small parcel weights in grams to freight loads in metric tons. All conversions use internationally standardized conversion factors for maximum accuracy.
Formula
1 kilogram = 2.20462 pounds = 35.274 ounces = 1,000 grams 1 pound = 0.453592 kilograms = 16 ounces = 453.592 grams 1 ounce = 28.3495 grams = 0.0625 pounds 1 stone = 14 pounds = 6.35029 kilograms 1 metric ton = 1,000 kilograms = 2,204.62 pounds 1 gram = 0.03527 ounces = 0.002205 pounds
Worked Examples
Body Weight Conversion for Fitness
A person weighing 80 kg wants to know their weight in pounds for a US-based fitness app. Converting: 80 x 2.20462 = 176.37 lbs. In stone (used in the UK): 80 / 6.35029 = 12.6 stone, or 12 stone 8 pounds. These conversions are useful for setting goals on international fitness platforms and understanding weight references in different media.
Recipe Conversion: Baking a Cake
A British recipe calls for 225 grams of flour and 150 grams of sugar. Converting for a US kitchen: 225 g flour = 7.94 oz (approximately 8 oz or 1 cup) and 150 g sugar = 5.29 oz (approximately 3/4 cup). Precise weight measurements in grams produce more consistent baking results than volume measurements, which is why professional bakers prefer metric scales.
Airline Luggage Weight Check
Before an international flight with a 23 kg checked bag limit, a traveler weighs their suitcase at 48 pounds on a US scale. Converting: 48 x 0.4536 = 21.77 kg, which is under the 23 kg limit with 1.23 kg to spare. This verification prevents expensive excess baggage charges that can range from $50 to over $200 per bag.
Shipping Package Weight
A seller ships a product internationally that weighs 3 pounds 8 ounces. Converting: 3.5 lbs x 0.4536 = 1.588 kg, or 1,588 grams. International shipping rates are typically calculated in kilograms, so this conversion determines the correct postage. For customs declarations, the weight must often be stated in kilograms to the nearest 100 grams.
Complete Weight Conversion Reference
| Unit | Kilograms | Pounds | Ounces | Grams | Stone |
|---|---|---|---|---|---|
| 1 Kilogram | 1 | 2.205 | 35.274 | 1,000 | 0.1575 |
| 1 Pound | 0.4536 | 1 | 16 | 453.6 | 0.0714 |
| 1 Ounce | 0.02835 | 0.0625 | 1 | 28.35 | 0.00446 |
| 1 Gram | 0.001 | 0.002205 | 0.03527 | 1 | 0.000157 |
| 1 Stone | 6.350 | 14 | 224 | 6,350 | 1 |
| 1 Metric Ton | 1,000 | 2,204.6 | 35,274 | 1,000,000 | 157.5 |
Common Body Weight Conversions
| Kilograms | Pounds | Stone & Pounds |
|---|---|---|
| 50 kg | 110.2 lbs | 7 st 12 lbs |
| 55 kg | 121.3 lbs | 8 st 9 lbs |
| 60 kg | 132.3 lbs | 9 st 6 lbs |
| 65 kg | 143.3 lbs | 10 st 3 lbs |
| 70 kg | 154.3 lbs | 11 st 0 lbs |
| 75 kg | 165.3 lbs | 11 st 11 lbs |
| 80 kg | 176.4 lbs | 12 st 8 lbs |
| 85 kg | 187.4 lbs | 13 st 5 lbs |
| 90 kg | 198.4 lbs | 14 st 2 lbs |
| 95 kg | 209.4 lbs | 14 st 13 lbs |
| 100 kg | 220.5 lbs | 15 st 10 lbs |
| 110 kg | 242.5 lbs | 17 st 5 lbs |
| 120 kg | 264.6 lbs | 18 st 13 lbs |
Common Cooking Weight Conversions
| Grams | Ounces | Pounds & Ounces | Common Measure |
|---|---|---|---|
| 15 g | 0.53 oz | - | 1 tablespoon butter |
| 28 g | 1 oz | 1 oz | - |
| 100 g | 3.53 oz | 3.5 oz | - |
| 113 g | 4 oz | 4 oz (1/4 lb) | 1 stick butter (US) |
| 150 g | 5.29 oz | 5.3 oz | - |
| 200 g | 7.05 oz | 7 oz | - |
| 227 g | 8 oz | 8 oz (1/2 lb) | - |
| 250 g | 8.82 oz | 8.8 oz | - |
| 340 g | 12 oz | 12 oz (3/4 lb) | - |
| 454 g | 16 oz | 16 oz (1 lb) | - |
| 500 g | 17.64 oz | 1 lb 1.6 oz | - |
| 1,000 g | 35.27 oz | 2 lb 3.3 oz | 1 kilogram |
Benefits of Using This Calculator
- Convert body weight between kilograms, pounds, and stone for fitness and medical use
- Translate cooking recipe measurements between grams and ounces accurately
- Calculate luggage weight for airline baggage limits in both kg and lbs
- Determine shipping costs by converting package weight between measurement systems
- Compare product weights when shopping from international retailers online
- Convert nutritional information on food labels between metric and imperial
- Essential for international trade, customs declarations, and logistics
- Support for all common weight units from milligrams to metric tons
Practical Tips
- For quick kg to lbs conversion, multiply by 2.2. For lbs to kg, multiply by 0.45. These approximations are accurate within 0.2 percent.
- When checking airline baggage, weigh your luggage at home with a bathroom scale: stand on the scale holding the bag, then subtract your own weight.
- In cooking, invest in a digital kitchen scale that shows both grams and ounces. Weight-based measurements are far more accurate than volume-based cups and spoons.
- Remember that 1 pound equals 16 ounces (not 10), and 1 stone equals 14 pounds. These non-decimal relationships are a key difference from the metric system.
- For shipping, round up to the next 0.5 kg or next pound as carriers typically charge by the next weight increment, not exact weight.
Related Concepts
Mass vs Weight
Mass is an intrinsic property of matter measured in kilograms, while weight is the force of gravity on that mass, technically measured in newtons. On Earth, a 1 kg mass weighs approximately 9.81 newtons. In everyday language and commerce, mass and weight are used interchangeably because we always measure on Earth where gravity is essentially constant.
Troy Ounces (Precious Metals)
Troy ounces (31.1035 grams) are used exclusively for precious metals like gold, silver, and platinum. A troy ounce is approximately 10 percent heavier than a regular avoirdupois ounce (28.3495 grams). When gold is quoted at a price per ounce, it always refers to the troy ounce. A troy pound contains 12 troy ounces, not 16 like a standard pound.
Metric Ton vs Short Ton
A metric ton (tonne) equals 1,000 kg or 2,204.6 lbs, used internationally. A short ton equals 2,000 lbs or 907.2 kg, used in the United States. A long ton equals 2,240 lbs or 1,016 kg, historically used in the UK. The differences of 5-10 percent between these units can cause significant errors in large-scale commerce and shipping if not properly identified.
Carat (Gemstones)
The carat is a unit of mass used for gemstones and pearls, equal to exactly 200 milligrams (0.2 grams). It should not be confused with karat, which measures the purity of gold. A 1-carat diamond weighs 0.2 grams or 0.00705 ounces. The carat was historically based on the carob seed, which was believed to have remarkably uniform weight.
Key Takeaways
- 11 kilogram equals 2.20462 pounds, and 1 pound equals 0.453592 kilograms.
- 2The stone (14 pounds or 6.35 kg) is commonly used in the UK and Ireland for body weight.
- 3Cooking conversions between grams and ounces are essential for following international recipes accurately.
- 4Airline baggage limits are typically 23 kg (50.7 lbs) for economy, so knowing both units prevents overweight fees.
- 5The kilogram was redefined in 2019 based on the Planck constant, making it the most precisely defined unit of mass.
Frequently Asked Questions
Mass is the amount of matter in an object, measured in kilograms, and remains constant regardless of location. Weight is the force of gravity acting on that mass, technically measured in newtons. On Earth, the distinction is negligible for everyday purposes, and the terms are used interchangeably in common language. However, an object with a mass of 70 kg would weigh approximately 70 kg on Earth but only about 11.6 kg on the Moon due to weaker gravity, while its mass remains 70 kg in both places.
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