What Is a Weight Converter?
A weight converter is a calculation tool that translates a mass or weight measurement from one unit to another — for example, converting kilograms to pounds, grams to ounces, or stone to kilograms. It is used daily by fitness enthusiasts tracking body weight across metric and imperial records, home cooks following international recipes, shipping departments calculating parcel costs, medical professionals referencing patient weight, and engineers applying ISO mass standards.
Weight measurement is one of the most geographically divided unit systems in the world. The United States uses pounds and ounces for both body weight and cooking. The United Kingdom uses stone for body weight and kilograms or pounds for everything else. Most other countries use kilograms and grams exclusively. South Asian markets use the tola (gold jewellery), and East Asian markets use the tael. This tool covers all of them.
How to Use This Weight Converter
Results update in real time as you type.
- Enter the weight value — Type the numeric mass or weight you want to convert. Decimals are fully supported.
- Select the source unit — Choose the unit your original measurement is in.
- Select the target unit — Choose the unit you need the result in.
- Read the result — The converted value appears instantly with full-precision output.
Supported Weight Units
- Metric: microgram (μg), milligram (mg), gram (g), kilogram (kg), metric tonne (t)
- Imperial / US Customary: ounce (oz), pound (lb), stone (st), US short ton (2,000 lb), UK long ton (2,240 lb)
- Troy (precious metals): troy ounce (t oz), troy pound
- Asian traditional: tola (India, Pakistan), tael / liang (China, Hong Kong), catty, momme (Japan)
Key Weight Conversion Factors
Kilograms ↔ Pounds
1 kg = 2.20462262185 lb. This is the most commonly used weight conversion globally — for body weight records, fitness app data, gym equipment specifications, and international medical charts. The exact conversion is defined by international agreement: 1 pound = 0.45359237 kg exactly.
Grams ↔ Ounces
1 oz = 28.349523125 g. Used extensively in food portion labels (particularly on US-market packaging), cooking recipes, and postal weight limits for letters and parcels.
Stone ↔ Kilograms
1 stone (st) = 14 lb = 6.35029318 kg. Stone is used almost exclusively in the UK and Ireland for human body weight. A person who weighs 75 kg is approximately 11 st 11 lb in UK convention. Note: stone is never used for goods, only for people.
Metric Tonne vs US Ton vs UK Ton
Three different quantities share similar names:
- Metric tonne (t): 1,000 kg = 2,204.62 lb — the international standard used in trade, shipping, and scientific contexts.
- US short ton: 2,000 lb = 907.185 kg — used in US domestic freight, coal, and steel industry.
- UK long ton: 2,240 lb = 1,016.05 kg — used in older UK industrial contexts and some Commonwealth references.
Always specify which “ton” is meant in any international document.
Troy Ounce (Precious Metals)
1 troy ounce = 31.1034768 g — approximately 10% heavier than a standard (avoirdupois) ounce (28.35 g). Gold, silver, platinum, and palladium spot prices are always quoted in troy ounces. Confusing the two when calculating the value of a gold holding is a costly error.
Tola (South Asia)
1 tola = 11.6638 g. The tola is the traditional unit for gold and silver in India, Pakistan, Nepal, and Bangladesh. Gold prices are commonly quoted per 10 grams and per tola in South Asian markets. 1 tola = approximately 0.375 troy ounces.
Weight by Application Domain
Fitness & Body Weight
Body weight is measured in kg across most of the world and in lb in the United States. The UK uses both: official NHS records use kg; informal everyday usage uses stone and pounds. Fitness apps often store internally in kg but display in the user’s preferred unit. Converting accurately between kg and lb is critical to avoid misreading progress — a 1 lb gain appears as only 0.45 kg, while a 1 kg loss shows as 2.2 lb.
Cooking & Baking
US recipes use ounces and pounds for dry ingredients; UK and European recipes use grams. The difference matters: 8 oz in a US recipe is 226.8 g, not 250 g (which is the metric “cup” of flour at certain densities). When adapting recipes internationally, always convert weights, not volumes, for precision baking.
Shipping & Logistics
International shipping rates are calculated in kg (metric) for most carriers globally. US domestic couriers (UPS, FedEx) use lb for domestic shipments. Customs declarations require kg. Converting accurately prevents misquoted freight costs and customs penalties.
Medical & Pharmaceutical
Drug dosing is typically weight-based (mg per kg of body weight). Clinical records globally use kg. US hospitals increasingly use kg for dosing safety; errors from lb/kg confusion have historically caused medication overdoses. Always confirm the unit system used in any clinical document before calculating doses.
Example Calculations
Example 1 — Body Weight Record
Scenario: A US patient weighs 185 lb. A European doctor needs this in kilograms.
185 lb × 0.453592 = 83.91 kg.
Example 2 — Baking Recipe
Scenario: A UK recipe calls for 500 g of flour. A US cook needs this in ounces.
500 g ÷ 28.3495 = 17.64 oz.
Example 3 — Gold Jewellery (Tola)
Scenario: A jeweller in Mumbai has 5 tola of gold. What is this in grams and troy ounces?
5 × 11.6638 = 58.319 g. In troy ounces: 58.319 ÷ 31.1035 = 1.876 troy oz.
Example 4 — Shipping Parcel
Scenario: A parcel weighs 3.5 US short tons. A customs form requires metric tonnes.
3.5 × 907.185 kg = 3,175.1 kg ÷ 1,000 = 3.175 metric tonnes.
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