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Ounce Conversion Table
This comprehensive ounce conversion table shows how various units relate to ounces, a common unit for mass and weight. Use this reference for quick conversions between ounces and other common mass units.
| Conversion | To Unit | Multiplier |
|---|---|---|
| Ounces to kilograms | Kilograms | 0.0283495 |
| Ounces to grams | Grams | 28.3495 |
| Ounces to milligrams | Milligrams | 28349.5 |
| Ounces to micrograms | Micrograms | 28349500 |
| Ounces to tonnes | Tonnes | 2.83495e-5 |
| Ounces to carats | Carats | 141.748 |
| Ounces to pounds | Pounds | 0.0625 |
| Ounces to stones | Stones | 0.00446429 |
| Ounces to grains | Grains | 437.5 |
| Ounces to hundredweight (short) | Hundredweight (short) | 0.000625 |
| Ounces to hundredweight (long) | Hundredweight (long) | 0.000558036 |
| Ounces to slugs | Slugs | 0.00194256 |
This ounce conversion reference table provides accurate conversion factors for both metric (SI) units and imperial units. All values are based on internationally recognized standards for maximum precision in scientific and engineering applications.
What is an Ounce?
The ounce (symbol: oz) is a unit of mass in the imperial and US customary systems of measurement. One ounce is equal to approximately 28.35 grams. The ounce is commonly used in the United States for measuring packaged food products, postal items, and portions in restaurants.
There are several definitions of the ounce, but the most commonly used is the avoirdupois ounce, which is defined as exactly 1/16 of a pound or approximately 28.349523125 grams. Our ounce conversion tool helps you easily convert between ounces and other units. For example, 16 ounces equals 1 pound or approximately 453.6 grams.
What is the SI of Ounce?
The ounce is not an SI unit, but it's commonly used in countries that utilize the imperial or US customary systems. The SI unit for mass is the kilogram. However, the ounce can be converted to SI units for scientific and international applications:
- Kilogram (kg) = 0.0283495 ounces
- Gram (g) = 28.3495 ounces
- Milligram (mg) = 28349.5 ounces
- Microgram (µg) = 28349500 ounces
What are Ounces Used For?
Ounces are used in a wide range of applications, particularly in the United States and other countries using the imperial system. As a convenient unit for measuring smaller weights, ounces provide a standard for weight conversions:
Food & Nutrition
Food packaging, nutritional labels, and portion control. For example, a standard chocolate bar might weigh 1.5 ounces or a serving of meat might be 4 ounces.
Postal Services
Calculating postage for letters and small packages. For example, determining that a 6-ounce envelope requires additional postage beyond the standard 1-ounce first-class stamp.
Manufacturing
Product specifications and quality control for small items. For example, ensuring a smartphone weighs exactly 6.1 ounces during production.
Retail
Pricing items by weight and inventory management. For example, loose coffee beans priced at $0.25 per ounce or precious metals sold by the ounce.
Etymology and History
The word "ounce" comes from the Latin "uncia," which was a unit of measurement in ancient Rome. The uncia was 1/12 of a Roman foot or 1/12 of a Roman pound (libra). When the avoirdupois system was developed in medieval England, the ounce became 1/16 of a pound instead, which is the definition we use today.
The modern definition of the ounce is based on the international avoirdupois pound, which is defined as exactly 0.45359237 kilograms. This makes one ounce exactly 28.349523125 grams. This evolution reflects the standardization of measurement systems and the need for consistent weight units in international trade.
Frequently Asked Questions
Why is the ounce used instead of grams?
The ounce is commonly used in the United States because it's part of the US customary system, which is still the primary system for everyday measurements in that country. While the metric system (using grams) is more common internationally, many Americans are more familiar with ounces for measuring food, packages, and body weight. Our ounce conversion tool helps bridge this gap when needed.
How accurate is the ounce definition?
The current definition of the ounce is extremely accurate, based on the international avoirdupois pound which is defined as exactly 0.45359237 kilograms. This makes one ounce exactly 28.349523125 grams. This definition ensures consistency in scientific research, commercial transactions, and international trade where precision is crucial.
What's the difference between fluid ounces and ounces?
There is a significant difference. Fluid ounces (fl oz) measure volume (how much space a liquid takes up), while ounces (oz) measure weight (how heavy something is). For example, 1 fluid ounce of water weighs approximately 1 ounce, but 1 fluid ounce of honey weighs about 1.5 ounces due to its higher density. Always use the appropriate unit for your measurement type.
How do I convert ounces to other units?
Use our ounce conversion calculators above, or multiply by the appropriate conversion factor. For example, to convert ounces to pounds, divide by 16; to convert ounces to grams, multiply by 28.35. For detailed instructions on converting ounces to pounds, visit our oz to lb converter. Our tool also handles metric conversions like ounces to kilograms with high precision.
What are common uses for ounce conversion?
Ounce conversion is essential in cooking (ingredient measurements), shipping (package weights), shopping (product pricing), health (nutritional information), and science (laboratory samples). Whether calculating nutritional intake or determining shipping costs, our ounce converter tool simplifies these everyday tasks.
How does ounce conversion differ from other weight units?
The ounce is a smaller unit compared to pounds and kilograms, making it convenient for measuring lighter items. In the imperial system, 16 ounces equal 1 pound. In the metric system, 1 ounce equals approximately 28.35 grams. This relationship makes ounce conversion particularly useful for small weight measurements compared to larger units like kilograms or stones.
Can I convert very small or very large measurements in ounces?
Yes, our ounce converter handles both extremely small and large measurements with precision. For microscopic work, convert micrograms to ounces (1 µg = 3.5274e-8 oz). For large quantities, convert ounces to tonnes (1 t = 35274 oz). Our smart rounding feature ensures readable results for all scales.
Is your ounce conversion tool free to use?
Yes, our ounce conversion calculator is completely free with no registration required. Simply enter your value, select your target unit, and get instant, accurate results. We believe precise measurement conversion should be accessible to everyone, from students learning about weight units to professionals working on complex projects.