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Weight Conversion Calculator

Convert mass and weight between metric units (milligrams, grams, kilograms, tonnes) and imperial/customary units (ounces, pounds, troy ounces, stones,

Conversions
Weight or mass quantity to convert.
Starting weight unit.
Destination weight unit.
Formula & Methodology
Target Mass = Starting Mass × (Factor_From ÷ Factor_To)

All masses convert via the international kilogram defined by the Planck constant. 1 avoirdupois pound equals exactly 0.45359237 kg. 1 troy ounce equals exactly 480 grains (31.1034768 g), whereas 1 avoirdupois ounce is 1/16 pound (28.349523 g). 1 US short ton is 2,000 lb, 1 UK long ton is 2,240 lb, and 1 metric tonne is 1,000 kg.

Kilograms Result

68.038855 kg

Overview

Convert mass and weight between metric units (milligrams, grams, kilograms, tonnes) and imperial/customary units (ounces, pounds, troy ounces, stones, short tons, long tons). Crucially, this tool distinguishes between ordinary avoirdupois ounces (28.35 g) and precious metal troy ounces (31.10 g), as well as US short tons, UK long tons, and metric tonnes.

Worked Examples

Convert 150 Pounds to Kilograms

Input 150 lb converted to kg.

  1. 1 pound = 0.45359237 kg exactly.
  2. Compute: 150 × 0.45359237 = 68.0388555 kg.
Final Answer: 68.038856 kg

Convert 1 Troy Ounce to Grams (Gold Weight)

Input 1 troy oz converted to grams.

  1. 1 troy ounce = 480 grains.
  2. 1 grain = 0.06479891 g.
  3. Compute: 480 × 0.06479891 = 31.1034768 g exactly.
Final Answer: 31.103477 g

Convert 1 US Short Ton vs 1 UK Long Ton to Kilograms

Compare 1 short ton and 1 long ton in kg.

  1. 1 US Short Ton = 2,000 lb × 0.45359237 kg/lb = 907.18474 kg.
  2. 1 UK Long Ton = 2,240 lb × 0.45359237 kg/lb = 1,016.04691 kg.
  3. 1 Metric Tonne = 1,000 kg exactly.
Final Answer: Short Ton: 907.18 kg | Long Ton: 1,016.05 kg

How to Use This Calculator

  1. Enter the mass or weight into the value field.
  2. Choose the origin unit (ensure troy ounces are chosen if measuring precious metals).
  3. Choose the desired target unit.
  4. Review the converted weight along with conversion factors and unit definitions.

Reference Table

Unit NameSymbolMass in KilogramsMass in Pounds
Gramg0.001 kg0.0022046 lb
Kilogramkg1.0 kg2.2046226 lb
Metric Tonnet1,000.0 kg2,204.6226 lb
Ounce (Avoirdupois)oz0.0283495 kg0.0625 lb (1/16 lb)
Troy Ounce (Gold)troy oz0.0311035 kg0.0685714 lb
Poundlb0.45359237 kg1.0 lb (exact)
Stone (UK)st6.3502932 kg14.0 lb (exact)
Short Ton (US)ton (US)907.18474 kg2,000.0 lb (exact)
Long Ton (UK)ton (UK)1,016.0469 kg2,240.0 lb (exact)

Frequently Asked Questions

What is the difference between an ounce and a troy ounce?
The ordinary avoirdupois ounce used for groceries equals 28.3495 grams (16 ounces per pound). The troy ounce used exclusively for precious metals like gold and silver equals 31.1035 grams (12 troy ounces per troy pound). A troy ounce is approximately 9.7% heavier than an ordinary ounce.
Is a US ton the same as a metric tonne?
No. A US short ton is 2,000 pounds (907.185 kg). A metric tonne is 1,000 kilograms (2,204.62 pounds). A British long ton is 2,240 pounds (1,016.05 kg).
What is a stone in British body weight?
A stone is an imperial unit of mass equal to exactly 14 avoirdupois pounds (6.35029 kilograms). It remains commonly used in the United Kingdom and Ireland to report human body weight (e.g. 11 stone 4 pounds).
How is the international pound officially defined?
Since the 1959 International Yard and Pound Agreement, the international avoirdupois pound is legally defined as exactly 0.45359237 kilograms.
How many grams are in one avoirdupois pound?
There are exactly 453.59237 grams in one avoirdupois pound (0.45359237 kg × 1,000 g/kg).

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Reviewed & Authored by: OnlineConvers Engineering Team · Last Updated: 2026-10-07
Conversions utilize exact constants established by the NIST Handbook 44 and the UK Weights and Measures Act. The avoirdupois pound is 0.45359237 kg exact; the troy ounce is 480 grains of 64.79891 mg exact.