Convert Ounces to Grams – Weight Converter
This converter converts a value in ounces to grams using the internationally recognized definition of the avoirdupois ounce. It is intended for everyday conversions as well as for laboratory and regulatory contexts where clarity about unit type and precision matters.
The tool distinguishes common practical considerations: which ounce type is in use, how many significant digits to report, and when to consider measurement uncertainty. When accuracy or compliance is required, follow calibration and reporting guidance from standards organizations.
Interactive Converter
Convert between ounce and gram with precision rounding.
Quick reference table
| Ounce | Gram |
|---|---|
| 1 oz | 28.3495 g |
| 5 oz | 141.7476 g |
| 10 oz | 283.4952 g |
| 25 oz | 708.7381 g |
| 50 oz | 1,417.4762 g |
| 100 oz | 2,834.9523 g |
Methodology
Definition used: 1 avoirdupois ounce equals exactly 28.349523125 grams. This conversion factor is the standard for common mass measurements and trade in countries using avoirdupois units.
For troy ounces (used for precious metals) a different conversion applies: 1 troy ounce = 31.1034768 grams. The converter defaults to the avoirdupois ounce; choose a troy-ounce aware tool when working with bullion or gemstones.
Accuracy guidance: observe calibration and uncertainty practices from national metrology guidance. For traceable measurements, use calibrated balances and report uncertainty according to NIST/ISO guidelines. Round results only after considering required significant figures for your use case.
Worked examples
1.0 oz → 28.349523125 g → report as 28.35 g if two decimal places are required
8.0 oz → 226.79618499999998 g → report as 226.80 g when rounding to two decimals
2.5 oz → 70.8738078125 g → report as 70.874 g when rounding to three decimals
Further resources
Expert Q&A
Which ounce does this converter use?
By default this converter uses the avoirdupois ounce (1 oz = 28.349523125 g). For precious metals priced by the troy ounce, use the troy conversion (1 troy oz = 31.1034768 g).
Why are different ounce values used in some contexts?
There are multiple historical definitions of the ounce. The two most common today are the avoirdupois ounce for general mass and the troy ounce for precious metals. Always confirm which ounce type your context requires.
How many decimal places should I report?
Report the number of decimal places or significant digits appropriate to your task. For cooking, two decimal places are usually sufficient. For laboratory or regulatory reporting, follow your lab's SOP and NIST/ISO uncertainty requirements.
Does this converter account for measurement error from my scale?
No. This tool performs exact mathematical unit conversion. It does not include measurement uncertainty from instruments. For traceable results, use a calibrated balance and include uncertainty following NIST and ISO guidance.
Is the conversion factor exact?
The avoirdupois ounce to gram factor used here is the defined value used in international practice. Measurement results will still be subject to instrument uncertainty and sampling error when weighing physical objects.
Are there safety or regulatory considerations when weighing materials?
Yes. Follow workplace safety and handling rules relevant to the material being weighed. For regulated substances or workplace exposure limits, consult safety standards and regulatory agencies for handling, calibration, and recordkeeping requirements.
Sources & citations
- NIST - Weights and Measures / Metric SI information — https://www.nist.gov/pml/weights-and-measures/metric-si
- BIPM - The International System of Units (SI Brochure) — https://www.bipm.org/en/publications/si-brochure
- ISO - International Organization for Standardization — https://www.iso.org/
- IEEE Standards Association — https://standards.ieee.org/
- OSHA - Occupational Safety and Health Administration — https://www.osha.gov/