Ounces to Grams Converter — Convert oz to g (Exact: g = oz × 28.349523125)
Accurate ounces (oz) to grams (g) converter using the exact international definition 1 oz = 28.349523125 g. Ideal for cooking, nutrition labels, e-commerce shipping, jewelry findings (avoirdupois), and lab work.
Exact factor: 1 oz = 28.349523125 g ⇒ g = oz × 28.349523125. Note: this is mass (oz), not fluid ounces (fl oz). For liquid volume, visit our volume metric converters.
About Ounces to Grams Conversion
The ounce (oz) is still common in U.S. recipes, retail packs, and shipping labels, while the gram (g) is the metric workhorse used by food science, nutrition regulation, and international trade. Converting ounces to grams makes your measurements portable across countries and standards. If you’re maintaining a global catalog or nutrition database, store your canonical mass in kilograms/grams for analytics and interchange, and compute ounces on the fly for region-friendly UI. Explore more at our weight unit converter.
Because the constant is exact—1 oz = 28.349523125 g—you can confidently publish transparent rounding policies (for example, 1 decimal place for recipe cards; 0.01 g for lab notes) and get reproducible results across exports, PDFs, and APIs.
Ounces to Grams Formula
Exact relationship
Use either expression:
g = oz × 28.349523125
// mental math
g ≈ oz × 28.35Example:
8 oz × 28.349523125 = 226.79618 gRelated Weight Converters
What is an Ounce (oz)?
The modern ounce used in everyday mass is the avoirdupois ounce. It is standardized so that one avoirdupois ounce equals exactly 28.349523125 grams. Do not confuse it with the fluid ounce (fl oz), which is volume, or the troy ounce (31.1034768 g) used for precious metals. This page converts the everyday mass ounce.
What is a Gram (g)?
The gram is an SI unit of mass equal to 1/1000 of a kilogram. It’s the standard for nutrition labels, lab notebooks, R&D protocols, and international trade. For fine measurements—espresso dosing, baking, supplement formulation—grams (and even tenths of a gram) provide practical precision with consumer scales.
Step-by-Step: Converting oz to g
- Read the mass in ounces (oz) from your recipe, label, or scale.
- Multiply by 28.349523125 to convert to grams (g).
- Round once at display time (e.g., 1 d.p. for home recipes; 0.01 g for lab notes).
Example walkthrough:
Input: 2.5 oz
Compute: 2.5 × 28.349523125 = 70.87381 g
Output: 70.9 g (UI, rounded); keep full precision internallyCommon Conversions
Everyday quick checks
| oz | g |
|---|---|
| 1 | 28.34952 |
| 2 | 56.69905 |
| 4 | 113.39810 |
| 8 | 226.79618 |
| 12 | 340.19428 |
| 16 (1 lb) | 453.59233 |
Precision, Rounding & Significant Figures
Operational rounding
For cooking, 1 d.p. in grams is usually sufficient; for baking, coffee, and compound dosing, 0.1 g or 0.01 g improves repeatability. Whatever you choose, round once at presentation time and store precise values to keep reports, emails, and exports consistent.
Consistent documentation
Standardize field names (e.g., mass_oz, mass_g, mass_kg), convert at one step in your pipeline, and publish constants/rounding in your methods note: “1 oz = 28.349523125 g; UI shows 1 decimal place.”
Where This Converter Is Used
- 🍰 Baking & recipe development: Convert U.S. oz recipes into grams for precision and scaling.
- 🥤 Nutrition & labeling: Regulatory tables and claims validated in grams while packaging shows oz.
- 📦 E-commerce shipping: Small parcels quoted in oz; customs and international listings in grams.
- 🔬 Labs & R&D: Protocols and SOPs record mass in grams; consumer summaries may include oz.
- ☕ Coffee & beverage: Dial-in dose and yield in grams while marketing copy references ounces.
Quick Reference Table
| g | oz |
|---|---|
| 50 | 1.76370 |
| 100 | 3.52740 |
| 150 | 5.29109 |
| 250 | 8.81849 |
| 500 | 17.63698 |
| 1000 (1 kg) | 35.27396 |
Frequently Asked Questions
What is the exact formula to convert ounces to grams?
Use the internationally fixed constant for the avoirdupois ounce: 1 oz = 28.349523125 g. Multiply ounces by 28.349523125 to get grams: g = oz × 28.349523125. This constant is exact and ensures your conversions match packaging, nutrition, and lab standards.
Is an ounce a unit of weight or volume? What about fluid ounces?
In this tool, ounce (oz) is a unit of mass. A fluid ounce (fl oz) is a unit of volume used for liquids and belongs in the volume calculators (e.g., fl oz ↔ mL). If a recipe calls for fl oz, use a volume conversion—not mass—unless the ingredient density is specified.
What’s the difference between an avoirdupois ounce and a troy ounce?
The converter on this page uses the modern avoirdupois ounce (common in everyday mass). A troy ounce—used for precious metals—is exactly 31.1034768 g and should not be mixed with food or parcel weights. If you need troy conversions, treat them as a separate system.
How precise should I be when converting oz to g for recipes?
Home cooking is usually fine with 1 decimal place in grams; baking and confectionery often benefit from 0.1 g or better. For nutrition and labeling, follow your regulatory precision rules. Internally, keep full precision and round once at display time to avoid drift.
Can I estimate quickly without a calculator?
Yes. A handy shortcut is to multiply by 28.35 (rounded) for a quick mental math result. For documentation, nutrition facts, or labeling, use the exact constant 28.349523125 and state your rounding policy.
Why do shipping labels sometimes toggle between ounces and pounds?
Carriers in the U.S. often accept both lb and oz for small parcels. Converting oz → g lets you align with international customs forms and product catalogs, which tend to be metric-first. For auditability, store mass in kilograms or grams and compute oz for labels.
Is it better to store grams or kilograms in my database?
Either works. Many teams store kilograms (SI base for mass) and compute grams/ounces for UI, while others store grams for integer arithmetic. Pick a canonical unit, document it, and convert at the edges. Consistency is more important than which unit you choose.
Do all kitchen scales measure in grams and ounces?
Most digital kitchen scales toggle between grams and ounces. For sticky ingredients or tare adjustments, grams provide finer control. For U.S. cookbooks, ounces are common—this converter bridges both worlds with exact, reproducible math.
What if my recipe lists volume units but I want grams?
You’ll need ingredient density (mass per volume). Convert volume to mass using density, then if required convert to grams. Without density, a direct fl oz → g conversion isn’t valid because volume and mass are different physical quantities.
Tips for Working with Ounces & Grams
- Keep SI (kg/g) canonical for analytics and compliance; compute ounces for region-friendly UI.
- Document a single rounding policy (e.g., 0.1 g for recipes) and reuse it across PDFs, exports, and emails.
- Don’t mix fluid ounces (volume) with mass ounces; if you must convert fl oz → g, include density in your method.