Weight Converter
Convert between kilograms, pounds, ounces, stones, and more weight units. Get instant accurate conversions with helpful weight references across metric, imperial, and scientific systems.
Weight Input
Common metric weight unit
Unit Categories
Quick Set
Enter a Weight
Please enter a weight value to see instant conversions across all weight units with helpful references and category filtering.
How to Convert Weight
Enter Weight
Type any weight value in the input field. Supports very precise measurements from milligrams to tons.
Select Unit
Choose from metric (kg, g), imperial (lb, oz), precious metals (carat, troy oz), or scientific units.
Filter Categories
Use category filters to focus on specific weight systems: metric, imperial, precious metals, or scientific.
Copy Results
Click copy buttons to save converted values for shipping, recipes, scientific work, or precious metal trading.
Weight Measurement Systems
Metric System
International standard system based on the kilogram and gram.
- • Milligrams (mg) - Very small weights
- • Grams (g) - Base unit, everyday items
- • Kilograms (kg) - Common weights
- • Metric tons (t) - Large masses
Imperial System
Traditional British and American weight measurements.
- • Ounces (oz) - Small to medium weights
- • Pounds (lb) - Common everyday weights
- • Stones (st) - British body weight
- • Tons - Large industrial weights
Precious Metals
Specialized units for gems, jewelry, and precious metals.
- • Carats (ct) - Gemstones and diamonds
- • Troy ounces (oz t) - Gold, silver, platinum
- • Different from regular ounces
- • International trading standard
Scientific Units
Extremely precise units for scientific measurements.
- • Atomic mass units (u) - Molecular weights
- • Extremely small measurements
- • Chemistry and physics research
- • Particle and nuclear physics
Common Weight Conversions
Metric Conversions
Imperial Conversions
Metric vs Imperial
Weight Converter Applications
Shipping & Logistics
Essential for international shipping and freight calculations.
- • Package weight for shipping costs
- • Container load calculations
- • International freight documentation
- • Customs and duty calculations
Cooking & Nutrition
Important for recipe scaling and nutritional analysis.
- • Recipe ingredient scaling
- • International recipe conversion
- • Nutritional content calculations
- • Portion control and meal planning
Scientific Research
Precise measurements for laboratory and field work.
- • Chemical compound measurements
- • Sample preparation and analysis
- • Medical dosage calculations
- • Materials science research
Precious Metals Trading
Critical for jewelry, gems, and precious metal transactions.
- • Gold and silver trading
- • Diamond and gemstone valuation
- • Jewelry manufacturing
- • Investment precious metals
Weight Conversion FAQ
What's the difference between mass and weight?
Mass is the amount of matter in an object (measured in kg), while weight is the force of gravity on that mass (measured in Newtons). In everyday use, we often use “weight” to mean mass.
Why are troy ounces different from regular ounces?
Troy ounces (31.10 g) are heavier than avoirdupois ounces (28.35 g) and are used specifically for precious metals. This system dates back to medieval European trading.
How accurate are the weight conversions?
Our conversions use precise mathematical relationships and display results to 6 decimal places, providing accuracy suitable for scientific, commercial, and precious metal applications.
Which weight units should I use for international shipping?
Most international shipping uses kilograms (metric system). However, check with your carrier as some US-based companies may use pounds for domestic and international shipments.