Weight Converter

Q: How do I convert kilograms to pounds?

Multiply kilograms by 2.20462 to get pounds. For example, 75 kilograms multiplied by 2.20462 equals 165.35 pounds. To convert pounds to kilograms, divide by 2.20462 or multiply by 0.45359. The converter handles this instantly when you select Kilogram as the source unit and Pound mass as the destination unit.

Q: What is the difference between a troy ounce and a regular ounce?

A troy ounce is 31.103 grams, while a regular avoirdupois ounce is 28.350 grams. A troy ounce is about 9.7 percent heavier. Troy ounces are used specifically for precious metals such as gold, silver, platinum, and palladium. The regular ounce is used for food, postal weight, and most everyday measurements. Using the wrong ounce type can create a significant error in precious metal calculations.

Q: What is the difference between a short ton, long ton, and metric ton?

There are three main ton definitions in use. A short ton, used in the United States, equals 2000 pounds or 907.185 kilograms. A long ton, used historically in the United Kingdom, equals 2240 pounds or 1016.047 kilograms. A metric ton, also called a tonne, equals 1000 kilograms or 2204.623 pounds. A short ton is about 10 percent lighter than a metric ton, while a long ton is about 1.6 percent heavier than a metric ton.

Q: What is a metric carat?

A metric carat, written as ct, is the standard unit used for gemstone weight. One carat equals 0.2 grams or 200 milligrams. A 1-carat diamond therefore weighs exactly 0.2 grams. Gemstone prices are commonly quoted per carat, so carat weight directly affects value. This is different from gold purity expressed in carats, such as 18-carat gold, which describes purity rather than mass.

Q: What is the atomic mass unit (amu)?

The atomic mass unit, also called the Dalton and abbreviated as amu or Da, is used in chemistry and physics to express the masses of atoms and molecules. One atomic mass unit is approximately 1.6605 × 10⁻²⁷ kilograms. It is roughly the mass of one proton or neutron. For example, the molecular mass of water, H2O, is about 18 amu. This unit is mainly used in chemistry, biochemistry, and materials science rather than in everyday weight measurements.

Q: How many grams in an ounce?

One avoirdupois ounce, the everyday ounce used in cooking, food labeling, and postal weight, equals 28.3495 grams. For quick estimation, 1 ounce is about 28 grams. For precious metals, use the troy ounce instead, where 1 troy ounce equals 31.103 grams.

Q: Why does the converter list both 'Tonne' and 'Ton (metric)' — are they the same?

Yes. Tonne and metric ton are exactly the same unit, equal to 1000 kilograms. Tonne is the standard spelling in most English-speaking countries outside the United States, while metric ton is the term more commonly used in the United States to distinguish it from the short ton. Both names represent the same measurement and produce identical conversion results.

Convert weight units instantly—grams (g), kilograms (kg), pounds (lb), ounces (oz), and more. Enter a value, choose units, and get accurate conversions in seconds. Perfect for shipping, cooking, fitness, and technical work. Free, fast, and easy to use.

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Weight Converter

The Weight Converter converts between 17 mass units across four systems: metric SI (microgram through metric ton), Imperial/US customary avoirdupois (ounce through long ton), the troy system used for precious metals and gemstones (troy ounce, troy pound, carat), and the atomic mass unit used in chemistry and physics. Enter a value, select the From and To units, and click Convert.

Weight units vary significantly by industry, country, and era. Everyday shopping and shipping uses kilograms or pounds; precious metals trade globally in troy ounces; HVAC and pharmaceutical applications use grams and milligrams; bulk commodities use tons — but which ton depends on whether you are in the US, UK, or following international standards. The unit reference table below covers every supported unit with its kilogram equivalent and typical context.

How to use the Weight Converter

Enter the value to convert in the input field.
Select the From unit — the unit your value is currently expressed in.
Select the To unit — the unit you want to convert to.
Click Convert. The result appears immediately.
To convert the same value to additional units, change the To dropdown and click Convert again without re-entering the value.

All 17 units — conversion factors and typical contexts

Unit	In kilograms (kg)	Typical context
Metric / SI units
Microgram (µg)	0.000 000 001 kg	Pharmaceutical dosing, trace element analysis, laboratory chemistry. Active pharmaceutical ingredients may be dosed in micrograms (e.g. levothyroxine doses are measured in µg).
Milligram (mg)	0.000 001 kg	Medication doses, supplement amounts, small-quantity chemical measurements. Paracetamol tablets are typically 500 mg; vitamin D supplements in mcg/µg.
Gram (g)	0.001 kg	Cooking ingredients, small postal items, jewelry, food labelling, laboratory work. The standard unit for recipe measurements in most countries.
Kilogram (kg)	1 kg	The SI base unit of mass. Human body weight, produce, most everyday items. Standard unit for shipping weight in metric countries.
Metric Ton / Tonne (t)	1,000 kg	Bulk cargo, vehicles, industrial materials, CO₂ emissions reporting, agricultural yields. 1 metric ton = 1,000 kg = 1 tonne. The 'Tonne' and 'Ton (metric)' entries in the tool are the same unit.
Imperial / US customary (avoirdupois system)
Ounce (oz) — avoirdupois	0.028 350 kg	Cooking and baking in the US and UK, food product labelling (US), small postal parcels. The everyday 'ounce' — 16 oz = 1 lb. Not the same as a troy ounce.
Pound (lb) — avoirdupois	0.453 592 kg	Body weight and fitness in the US/UK, food packaging, shipping weights for US carriers (UPS, FedEx, USPS), US and UK product specifications.
Hundredweight (short, cwt)	45.359 kg	US agricultural commodity trading (grain, livestock). 1 short cwt = 100 lb. Used in US feed and grain markets.
Hundredweight (long, cwt)	50.802 kg	UK/Commonwealth agricultural and commodity markets. 1 long cwt = 112 lb. Used in UK grain, hay, and livestock trading. Different from the US short hundredweight.
Ton (short)	907.185 kg	US construction, mining, agriculture, and freight. 1 short ton = 2,000 lb. When a US specification says 'ton' without qualification, it typically means the short ton.
Ton (long)	1,016.047 kg	UK and Commonwealth bulk shipping, maritime cargo, historical UK industry. 1 long ton = 2,240 lb. When a UK specification says 'ton', it typically means the long ton.
Troy system (precious metals and gemstones)
Ounce (troy, ozt)	0.031 103 kg	Gold, silver, platinum, palladium pricing and trading globally. All precious metal spot prices are quoted per troy ounce. 1 troy oz = 31.103 g vs 1 avoirdupois oz = 28.350 g — a troy ounce is heavier.
Pound (troy, lbt)	0.373 242 kg	Historical precious metals trading. Rarely used in modern markets (spot prices use troy ounces). 1 troy pound = 12 troy ounces — note that a troy pound (373 g) is lighter than an avoirdupois pound (453 g).
Carat (metric, ct)	0.000 200 kg	Gemstone weight — diamonds, rubies, emeralds, and other precious and semi-precious stones. 1 metric carat = 0.2 g = 200 mg. The quality metric 'carat' for gold purity (24 carat gold) is a different use of the word and is not a mass unit.
Ton (assay, AT)	0.029 167 kg (short AT)	Metallurgical assaying — the amount of ore needed for a standard assay test. Short assay ton (US) = 29.167 g; long assay ton (UK) = 32.667 g. Used by mining laboratories. Rarely encountered outside the mining industry.
Scientific unit
Atomic Mass Unit (amu / Da)	1.6605 × 10⁻²⁷ kg	Atomic and molecular mass in chemistry and physics. The mass of one proton or neutron is approximately 1 amu. Molecular weight of water (H₂O) ≈ 18 amu. Not used for practical everyday mass measurements.

The ton problem — short, long, and metric are not the same

'Ton' is one of the most ambiguous units in everyday use because three distinct definitions exist and all are in active use:

Ton type	Mass (kg)	Mass (lb)	Where used
Short ton (US ton)	907.185 kg	2,000 lb	United States: construction, agriculture, freight, mining, bulk commodities.
Long ton (UK ton)	1,016.047 kg	2,240 lb	United Kingdom and Commonwealth: maritime cargo, historical bulk commodities.
Metric ton / Tonne	1,000.000 kg	2,204.623 lb	International standard. Science, international trade, CO₂ emissions, most non-US contexts.

When a document, contract, or shipping specification says 'ton', always verify which ton is intended. A US freight quote in short tons and a European quote in metric tons differ by approximately 10% — 1 short ton = 0.907 metric tons. For international bulk commodity trading, the metric ton (tonne) is the international standard and the safest default assumption unless the document explicitly states otherwise. The long ton is primarily encountered in UK maritime and historical documents.

Troy vs avoirdupois — why precious metals use different ounces

The avoirdupois system (the everyday pound and ounce used for food, shipping, and body weight) and the troy system (used for precious metals) share the name 'ounce' and 'pound' but refer to different masses:

1 avoirdupois ounce = 28.350 grams. Used for food, postal weight, most everyday contexts. 16 avoirdupois oz = 1 avoirdupois lb.
1 troy ounce = 31.103 grams. Used for gold, silver, platinum, palladium. All precious metal spot prices worldwide are quoted per troy ounce. 12 troy oz = 1 troy lb.
The troy ounce is heavier than the avoirdupois ounce by approximately 9.7%.
The troy pound (373.2 g) is lighter than the avoirdupois pound (453.6 g), because there are only 12 troy ounces in a troy pound vs 16 avoirdupois ounces in an avoirdupois pound.

When buying or selling gold, silver, or platinum, always use troy ounces — do not substitute avoirdupois ounces. If you have 100 grams of gold and want to know the troy ounce equivalent: 100 g ÷ 31.103 = 3.215 troy oz. If you mistakenly use avoirdupois ounces: 100 g ÷ 28.350 = 3.527 oz — an error of nearly 10%, which is material in precious metals transactions.

Common use cases and key conversions

Context	Common conversion	Notes
Shipping and e-commerce	kg ↔ lb	US carriers (UPS, FedEx, USPS) use pounds; most international carriers use kilograms. 1 kg = 2.205 lb. Also note that carriers may use dimensional weight (package volume ÷ DIM factor) rather than actual weight for large, light packages — always check carrier billing rules.
Cooking and baking	g ↔ oz, g ↔ lb	US recipes typically use oz and lb; UK and European recipes use g and kg. 1 oz = 28.35 g. Baking is weight-sensitive — use the converter for accurate ingredient amounts when adapting recipes across unit systems.
Body weight / fitness tracking	kg ↔ lb, kg ↔ st lb	US and some UK users track body weight in pounds; most other countries use kilograms. UK also uses stone (st) — not in the tool, but 1 stone = 14 lb = 6.350 kg. A person weighing 80 kg = 176.4 lb = 12 st 8 lb.
Precious metals trading	troy oz ↔ g, troy oz ↔ kg	Gold, silver, and platinum spot prices are quoted per troy ounce globally. 1 troy oz = 31.103 g. When buying or selling bullion by weight, always use troy ounces — do not substitute avoirdupois ounces (28.35 g).
Pharmaceutical and medical	mg ↔ g, µg ↔ mg	Medication doses in milligrams (mg) or micrograms (µg). 1 g = 1,000 mg = 1,000,000 µg. Common confusion: µg (microgram) is sometimes written as 'mcg' on product labels to avoid misreading 'µ' as 'm'.
Gemstone valuation	ct ↔ g	Diamond and gemstone weight in metric carats. 1 carat = 0.2 g = 200 mg. A 1-carat diamond weighs 0.2 g. Note: gold purity 'carat' (24 carat gold) is a different measurement — it is a ratio of purity, not a mass unit.
Bulk commodities and freight	ton (metric) ↔ ton (short) ↔ ton (long)	Specify the ton type when working with bulk commodities. US bulk freight uses short tons (2,000 lb); UK maritime uses long tons (2,240 lb); international trade uses metric tons (1,000 kg). A 10% discrepancy exists between short and metric tons.

Usage limits

Account type	Daily conversions
Guest	25 per day
Registered	100 per day

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Frequently asked questions

How do I convert kilograms to pounds?

Multiply kilograms by 2.20462 to get pounds. Example: 75 kg × 2.20462 = 165.35 lb. To convert pounds to kilograms, divide by 2.20462 (or multiply by 0.45359). The converter handles this instantly — select Kilogram as From and Pound mass as To, enter the value, and click Convert.

What is the difference between a troy ounce and a regular ounce?

A troy ounce is 31.103 grams; a regular (avoirdupois) ounce is 28.350 grams. The troy ounce is approximately 9.7% heavier. Troy ounces are used exclusively for precious metals — gold, silver, platinum, and palladium prices worldwide are quoted per troy ounce. The avoirdupois ounce is used for food, postal weight, and all other everyday contexts. Using the wrong ounce type introduces a significant error in precious metals calculations.

What is the difference between a short ton, long ton, and metric ton?

Three different 'ton' definitions are in active use: short ton (US) = 2,000 lb = 907.185 kg; long ton (UK) = 2,240 lb = 1,016.047 kg; metric ton / tonne = 1,000 kg = 2,204.623 lb. A short ton is approximately 10% lighter than a metric ton; a long ton is approximately 1.6% heavier than a metric ton. When a specification uses 'ton' without qualification, the intended definition depends on the country and industry — the metric ton is the international standard for most modern contexts.

What is a metric carat?

A metric carat (ct) is the standard unit for gemstone weight. 1 carat = 0.2 grams = 200 milligrams. A 1-carat diamond weighs exactly 0.2 g. Gemstone prices are typically quoted per carat, so the carat weight directly affects value. Note: gold purity is also described in 'carats' (e.g. 18-carat gold), but this is a completely different use of the word — it describes a ratio of purity (18 out of 24 parts gold), not a mass unit.

What is the atomic mass unit (amu)?

The atomic mass unit (amu), also called the Dalton (Da), is used in chemistry and physics to express the masses of atoms and molecules. 1 amu ≈ 1.6605 × 10⁻²⁷ kg — approximately the mass of one proton or one neutron. Molecular weight of water (H₂O) is approximately 18 amu (two hydrogen atoms at ~1 amu each plus one oxygen atom at ~16 amu). This unit is not used for practical everyday mass measurements but appears in chemistry, biochemistry, and materials science.

How many grams in an ounce?

1 avoirdupois ounce = 28.3495 grams. This is the everyday ounce used in cooking, food labelling, and postal weight. For quick estimation: 1 oz ≈ 28 g. For cooking conversions: 4 oz ≈ 113 g; 8 oz (half a pound) ≈ 227 g; 16 oz (1 lb) ≈ 454 g. For precious metals, use the troy ounce: 1 troy oz = 31.103 g.

Why does the converter list both 'Tonne' and 'Ton (metric)' — are they the same?

Yes — tonne and metric ton are exactly the same unit: 1,000 kilograms. The word 'tonne' is the standard spelling in most English-speaking countries outside the US (UK, Australia, Canada). 'Metric ton' is the term commonly used in the US to distinguish from the US short ton (2,000 lb). Both entries in the converter produce identical conversion results.

Is the Weight Converter free?

Yes. The converter is free within the daily usage limits shown above. Guest users can perform 25 conversions per day without creating an account. Registering a free ToolsPiNG account increases the daily limit to 100 conversions per day.