Weight Converter
Our free volume & weight converter handles weight conversions. See tables, ratios, and examples for quick reference.
Weight Converter
Calculator
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Formula: Target = Value x (Source g factor / Target g factor)
Worked example — 5 troy oz = 155.52 g = 5.49 regular oz
Formula
Target = Value x (Source g factor / Target g factor)
All weight conversions pass through grams as the base unit. Each unit has a fixed factor to grams: 1 kg = 1000 g, 1 lb = 453.592 g, 1 oz = 28.3495 g, 1 st = 6350.29 g. To convert between any two units, multiply the input by its gram factor, then divide by the target gram factor.
Worked Examples
Example 1: Gold Weight Conversion
Problem:Convert 5 troy ounces of gold to grams and regular ounces.
Solution:Grams: 5 x 31.1035 = 155.5175 g Kilograms: 155.5175 / 1000 = 0.1555 kg Avoirdupois ounces: 155.5175 / 28.3495 = 5.4857 oz
Result:5 troy oz = 155.52 g = 5.49 regular oz
Example 2: Shipping Weight
Problem:A package weighs 35 pounds. Convert to kilograms and ounces.
Solution:Kilograms: 35 x 0.453592 = 15.8757 kg Grams: 15,875.72 g Ounces: 35 x 16 = 560 oz
Result:35 lb = 15.88 kg = 560 oz
Frequently Asked Questions
What is the difference between mass and weight?
Mass measures the amount of matter in an object and is measured in kilograms, while weight is the gravitational force on that mass and is technically measured in newtons. On Earth, a 1 kg mass weighs about 9.81 newtons. In everyday language, mass and weight are used interchangeably since all measurements are taken on Earth. The distinction becomes important in physics and space travel where gravitational fields differ.
What is the difference between avoirdupois and troy ounces?
An avoirdupois ounce (the standard ounce) equals 28.3495 grams and is used for general-purpose weighing. A troy ounce equals 31.1035 grams and is used exclusively for precious metals like gold, silver, and platinum. Paradoxically, while a troy ounce is heavier than a regular ounce, a troy pound (12 troy ounces = 373.24 g) is lighter than a standard pound (16 ounces = 453.59 g) because troy pounds contain fewer ounces.
How do I convert between metric and imperial weight units?
The key conversion factors are: 1 kg = 2.20462 lb, 1 lb = 0.453592 kg, 1 oz = 28.3495 g, and 1 stone = 14 lb = 6.35029 kg. For quick mental math, double kilograms and add 10% to get pounds, or halve pounds and subtract 10% to get kilograms. This converter handles all these conversions automatically for twelve different weight units including specialized units like carats and grains.
What are grains and carats used for?
Grains are one of the oldest units of weight, equal to 0.0648 grams (about the weight of a single grain of wheat). They are still used in ammunition, gunpowder measurement, and pharmacology. Carats equal exactly 0.2 grams and are the standard unit for measuring gemstone weight. A 1-carat diamond weighs 200 milligrams. The term carat for gems should not be confused with karat, which measures gold purity.
Why are there different types of tons?
There are three main types of tons. The metric tonne equals 1,000 kg and is the international standard. The US short ton equals 2,000 pounds (907.185 kg) and is used in American commerce. The Imperial long ton equals 2,240 pounds (1,016.047 kg) and was historically used in British shipping. The metric tonne is closest to the long ton in size. Always verify which ton is meant in specifications to avoid costly errors in shipping and construction.
How do I convert kilograms into pounds and ounces?
First multiply the kilograms by 2.204623 to get decimal pounds. Take the whole number as pounds, then multiply the remaining fraction by 16 to get ounces, since an avoirdupois pound contains 16 ounces. For 3.5 kg, 3.5 multiplied by 2.204623 gives 7.716 lb, and 0.716 multiplied by 16 gives about 11.5 oz, so the answer is 7 lb 11.5 oz. This two step split is how baby weights and postal weights are normally reported in the US and UK.
Why is a pound defined as 0.45359237 kilograms rather than a rounder number?
Under the 1959 International Yard and Pound Agreement, the participating nations pegged the avoirdupois pound to the kilogram at exactly 0.45359237 kg to eliminate the small national differences that had existed until then. The value is not round because it was chosen to preserve the existing physical pound as closely as possible while tying it to the metric standard. Everything downstream inherits it: the ounce is that figure divided by 16, and the stone is it multiplied by 14.
What is the difference between net weight, gross weight and tare weight?
Net weight is the goods alone, tare weight is the packaging, pallet or container, and gross weight is the two added together. Shipping documents, freight rates and vehicle axle limits normally work from gross weight, while product labels and customs duty calculations typically use net weight. Converting units does nothing to reconcile the three, so a figure that seems too heavy after conversion is often a gross weight being compared against a net one rather than a unit error.
What is the difference between a kilogram and a kilogram-force?
The kilogram is a unit of mass, while the kilogram-force is the weight force that one kilogram of mass experiences under standard gravity, defined using 9.80665 metres per second squared, which makes 1 kgf equal to 9.80665 newtons. Spring scales, torque specifications and pressure units such as kgf per square centimetre use the force version. Confusing them silently introduces a factor of about 9.81, which is why engineering work in SI uses newtons for force and reserves the kilogram strictly for mass.
Why can I not convert grams to cups with a fixed factor?
Because grams measure mass and cups measure volume, so the relationship depends entirely on the density of the ingredient and how tightly it is packed. A cup of granulated sugar weighs substantially more than a cup of sifted flour, and the same flour scooped rather than spooned into the cup can differ by ten percent or more. Any gram to cup table is therefore ingredient specific and approximate, which is why baking recipes that need precision are written in grams and measured on a scale.
References
Background & Theory
1 pound = 0.45359237 kg, 1 ounce = 28.349523125 g and 1 stone = 6.35029318 kg - all exact by definition. Every imperial mass unit descends from the single 1959 definition of the international avoirdupois pound.
Conversion reference table
| Conversion | Equivalent | Exact or rounded? |
|---|---|---|
| 1 pound (avoirdupois) | 453.59237 grams | Exact by definition |
| 1 ounce (avoirdupois) | 28.349523125 grams | Exact (1/16 lb) |
| 1 stone | 6.35029318 kilograms (14 lb) | Exact |
| 1 short ton (US) | 907.18474 kilograms | Exact |
| 1 long ton (imperial) | 1,016.0469088 kilograms | Exact |
| 1 tonne | 1,000 kilograms = 2,204.62262 pounds | Exact / derived |
| 1 troy ounce | 31.1034768 grams | Exact - precious metals |
| 1 grain | 64.79891 milligrams | Exact (1/7000 lb) |
Mass and weight are distinct quantities that everyday language runs together. Everything in this table is a mass, unchanged whether the object sits on Earth, on the Moon or in orbit; weight is the force gravity exerts on that mass and is properly measured in newtons or pounds-force. The distinction matters for spring and load-cell scales, which measure force and therefore read differently as local gravity varies by about half a percent between the equator and the poles.
Reviewed for accuracy by Manoj Kumar, Mathematics Educator · Editorial policy
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