Weight & Mass Converter
About Weight and Mass Units
Mass is the amount of matter in an object, while weight is the force exerted by gravity. On Earth, they're often used interchangeably.
The SI base unit for mass is the kilogram (kg). Other common units include grams (g), pounds (lb), and ounces (oz).
About This Converter
This weight and mass converter supports a wide range of units including:
- Metric: micrograms, milligrams, grams, kilograms, metric tons
- Imperial: grains, drams, ounces, pounds, short tons, long tons
- Other: hundredweights (US and UK)
Use the converter above to quickly convert between any of these units. The result updates automatically as you type or change selections.
Export your results in TXT, HTML, PDF, or print them directly.
Weight and Mass Converter: Complete Guide
Accurate weight and mass conversions are essential in many aspects of daily life, from cooking and baking to scientific research and international trade. Our Weight and Mass Converter helps you make precise conversions between metric, imperial, and other measurement systems with ease.
Understanding Weight vs. Mass
What's the Difference?
Mass is a fundamental measurement of the amount of matter in an object, while weight is the force exerted on that mass by gravity. On Earth, mass and weight are often used interchangeably, but they are fundamentally different concepts.
- Mass is constant: An object's mass remains the same regardless of location
- Weight varies: An object's weight changes depending on gravitational force
- Measurement units: Mass is measured in kilograms, grams, etc., while weight is measured in newtons
Try Our Weight and Mass Converter
Use the interactive converter above to quickly convert between any supported units. Select the source and target units, enter a value, and see the result instantly.
How to Use the Converter
Step-by-Step Guide
- Select source unit: Choose the unit you're converting from in the "Convert from" dropdown
- Select target unit: Choose the unit you're converting to in the "Convert to" dropdown
- Enter value: Input the numerical value you want to convert
- View result: The converted value appears automatically in the results section
- Swap units (optional): Use the swap button to quickly reverse the conversion direction
- Export (optional): Save your conversion in your preferred format
The Conversion Formula
Conversion Formula
Result = Input Value × (From Factor / To Factor)
Where factors are defined relative to the kilogram (kg). For example, 1 gram = 0.001 kg, so the factor is 0.001.
Supported Units
| Unit | Factor (relative to kg) | System |
|---|---|---|
| Microgram (μg) | 1.0e-9 | Metric |
| Milligram (mg) | 0.000001 | Metric |
| Gram (g) | 0.001 | Metric |
| Kilogram (kg) | 1 | Metric |
| Metric ton (t) | 1000 | Metric |
| Grain (gr) | 0.00006479891 | Imperial |
| Dram (dr) | 0.45359237/256 | Imperial |
| Ounce (oz) | 0.45359237/16 | Imperial |
| Pound (lb) | 0.45359237 | Imperial |
| Short ton | 0.45359237*2000 | Imperial |
| Long ton | 0.45359237*2240 | Imperial |
Worked Example
Example: Convert 5 Pounds to Kilograms
From: Pound (lb) — factor: 0.45359237
To: Kilogram (kg) — factor: 1
Calculation: 5 × 0.45359237 / 1 = 2.26796 kg
Advantages of Using This Converter
- Comprehensive: Supports 19 different weight and mass units.
- Real-time: Results update as you type or change selections.
- History: Keeps track of recent conversions.
- Export: Save results as TXT, HTML, PDF, or print.
- Accurate: Uses precise conversion factors.
Pro Tip: Significant Figures
When converting between units, pay attention to significant figures. Our converter automatically formats results based on the magnitude of the number to ensure appropriate precision.
Practical Applications
- Cooking & Baking: Convert international recipe measurements.
- Science & Education: Standardize measurements for reports and experiments.
- International Trade: Convert product weights for customs and shipping.
- Health & Fitness: Track body weight and nutritional information.
Common Mistakes to Avoid
Avoid These Errors
- Confusing troy ounces with avoirdupois ounces: Troy ounces are for precious metals.
- Mixing metric tons with short/long tons: These are different values.
- Forgetting regional differences: A "ton" can mean different things in different countries.
- Incorrect significant figures: Don't report more decimal places than justified.
Frequently Asked Questions
What's the difference between a short ton and a long ton?
A short ton (US) equals 2,000 pounds, while a long ton (UK) equals 2,240 pounds. The metric ton (tonne) equals 1,000 kilograms.
Why are there 16 ounces in a pound?
The division dates back to the Roman libra. The modern 16-ounce pound evolved through historical measurement systems.
How accurate are the conversions?
Our converter uses precise conversion factors. For most practical purposes, results are exact. Scientific applications may require additional considerations.
Can I convert between weight and mass units?
In everyday use on Earth, we typically convert between units that measure mass (like kilograms and pounds) even though pounds are technically a unit of force.
What is a grain measurement used for?
The grain is traditionally used for measuring bullets, arrows, and in some pharmaceutical contexts.