Weight Converter
Convert between different units of weight measurement including milligrams, grams, kilograms, ounces, pounds, stones, tons, and more. Quick and accurate weight conversions.
Conversion Settings
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Conversion Result
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Enter a value and click "Convert" to start
About Weight Converter
A comprehensive weight and mass converter that handles precise conversions between metric and imperial weight units. This versatile tool supports conversions from tiny measurements like milligrams to large quantities like tons, making it perfect for various applications from cooking to industrial calculations.
Why use a Weight Converter?
Essential for international commerce, cooking, fitness tracking, and scientific applications where accurate weight conversions are critical. Eliminates guesswork and calculation errors when working with recipes from different countries, shipping calculations, or scientific measurements requiring precise mass conversions.
Who is it for?
Perfect for chefs and home cooks converting international recipes, fitness enthusiasts tracking body weight, scientists conducting research, and international traders calculating shipping weights. Also valuable for students learning measurement systems and professionals in manufacturing or logistics.
How to use the tool
Input your weight value in the designated field
Select the source weight unit from the comprehensive list
Choose your desired target unit for conversion
View the converted result
Use the result for cooking, shipping, or scientific calculations
Frequently Asked Questions
How do I convert weight (mass) units?
Enter the source value, pick the 'from' and 'to' units, and click Convert to see the result. Supports mg, g, kg, oz, lb, st (stone), tonne, US short ton, UK long ton, carat (ct). Copy the converted value to clipboard. Conversion runs entirely in your browser — values never leave the device. Results are shown to up to 12 significant digits with trailing zeros removed; there is no precision setting.
What weight (mass) units does this converter support?
mg, g, kg, oz, lb, st (stone), tonne, US short ton, UK long ton, carat (ct). The set covers SI base and derived units, common imperial/US-customary units, and domain-specific units where relevant. SI prefixes (k, M, G, m, μ, n) apply where applicable. For any unit not in the list that you need converted, mention it via feedback — the unit set evolves based on user requests.
How accurate is the weight (mass) conversion?
Conversions use the internationally-defined factors where they exist; the result is rounded to 12 significant digits for display. Conversions use exact factors (1 lb = 453.59237 g exactly; 1 oz = 28.349523125 g exactly). Output is rounded to 12 significant digits for display, and there is no setting to change that.
What's the formula to convert pounds to kilograms?
kg = lb × 0.45359237 (exactly). International shipping and logistics — invoice weights must match the destination country's expected unit. Also common in cooking when recipes use volume (cups) or weight in one system and you have a scale in another. For other weight (mass)-unit pairs, the tool applies the appropriate exact conversion factor automatically — no manual formula needed. Results are rounded to 12 significant digits, which is more than engineering specs typically need.
What's the key accuracy caveat for weight (mass) conversion?
**Ton ambiguity** — the most common error in weight conversion. The metric tonne is 1,000 kg. The US short ton is 907.185 kg. The UK long ton (imperial ton) is 1,016.047 kg. A 'ton of steel' means different things in different countries. Always specify which ton. Also note: mass (kg, what the tool measures) is different from weight (force, measured in Newtons) — colloquially they're used interchangeably but for physics they're not.
What's a common real-world use case for weight (mass) conversion?
International shipping and logistics — invoice weights must match the destination country's expected unit. Also common in cooking when recipes use volume (cups) or weight in one system and you have a scale in another.
What weight (mass) units are commonly confused?
**Tonne (metric) vs short ton (US) vs long ton (UK)** — 1,000 / 907 / 1,016 kg respectively. **'lb' (pound) vs 'kg'** — 1 lb ≈ 0.454 kg; '200 lb' is NOT 200 kg. **'Mass vs weight'** — kg measures mass; weight is mass × gravity (Newtons in SI).
How do I handle very large or very small weight (mass) values?
Use SI prefixes for clean scaling: kilo (10³), mega (10⁶), giga (10⁹), milli (10⁻³), micro (10⁻⁶), nano (10⁻⁹). For very large or very small results, the tool switches to exponent notation (e.g. 1.23e15) at 1e15 and above or below 1e-9. Conversions use exact factors (1 lb = 453.59237 g exactly; 1 oz = 28.349523125 g exactly). For data interchange, copy the value; it is shown to 12 significant digits.
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