Ounces to Grams: Cooking, Gold and Shipping for Americans
Published on June 13, 2026 · 9 min read
You are following a French baking recipe that lists flour in grams but your kitchen scale shows ounces. You are buying gold and the price is listed per troy ounce — but a European dealer quotes per gram. You are shipping a package internationally and the weight limit is 2 kg but your postal scale shows pounds and ounces. The ounce is one of the most versatile — and confusing — units Americans deal with. This guide covers all three types of ounce you will encounter.
Three Types of Ounce — Know the Difference
Before converting anything, you need to know which ounce you are dealing with. There are three completely different units all called "ounce":
Avoirdupois Ounce
= 28.3495 grams
Used for: food, body weight, shipping, everyday goods
16 oz = 1 pound
Troy Ounce
= 31.1035 grams
Used for: gold, silver, platinum, precious metals
12 troy oz = 1 troy pound
Fluid Ounce
= 29.5735 ml (US)
Used for: liquid volume — drinks, medicine, cooking liquids
8 fl oz = 1 US cup
The rest of this guide covers the avoirdupois ounce (cooking, shipping, everyday use) and the troy ounce (precious metals). For fluid ounces, see our Volume Converter.
The Exact Formula (Avoirdupois)
1 oz = 28.3495231 grams (exact)
Grams = Ounces × 28.3495
Ounces = Grams ÷ 28.3495
For cooking and everyday use, rounding to 28.35 grams per ounce is more than accurate enough. The error is less than 0.002%.
Mental Math Shortcuts
Trick 1: oz × 28 (fast kitchen estimate)
Multiply ounces by 28 for a fast estimate. Example: 4 oz × 28 = 112 g. Exact: 113.4 g. Close enough for baking where a 1% error does not matter.
Trick 2: grams → oz (divide by 28)
Divide grams by 28 for quick ounces. Example: 500 g ÷ 28 = 17.9 oz ≈ 18 oz. Exact: 17.64 oz. Good enough for shipping weight estimates.
Trick 3: Key anchor points
1 oz ≈ 28 g. 4 oz = 113 g (quarter pound). 8 oz = 227 g (half pound). 16 oz = 454 g (1 pound). 35 oz ≈ 1 kg. Memorize these and you can estimate anything in your head.
Complete Reference Table: Ounces to Grams
| Ounces | Grams | Context |
|---|---|---|
| ¼ oz | 7.09 g | Spice serving / small packet |
| ½ oz | 14.17 g | Protein powder scoop (small) |
| 1 oz | 28.35 g | Slice of cheese / shot of espresso |
| 2 oz | 56.70 g | Small chocolate bar |
| 3 oz | 85.05 g | Deck of cards / airline meat portion |
| 3.5 oz | 99.2 g | 100g chocolate bar (approx) |
| 4 oz | 113.4 g | Quarter pound / small chicken breast |
| 5 oz | 141.7 g | Standard wine pour (5 glasses per bottle) |
| 6 oz | 170.1 g | Medium chicken breast |
| 8 oz | 226.8 g | Half pound / standard steak (small) |
| 10 oz | 283.5 g | Large steak (restaurant portion) |
| 12 oz | 340.2 g | Can of soda / can of beer |
| 14 oz | 396.9 g | Large can of beans |
| 16 oz | 453.6 g | 1 pound — butter, ground beef block |
| 20 oz | 567.0 g | Large soda bottle |
| 24 oz | 680.4 g | Large coffee (Starbucks Venti) |
| 28 oz | 793.8 g | Large can of crushed tomatoes |
| 32 oz | 907.2 g | 2 pounds / quart of liquid |
| 35.27 oz | 1000 g | 1 kilogram exactly |
| 48 oz | 1360.8 g | 3 pounds / large yogurt container |
Baking: Why Grams Beat Ounces
Professional bakers worldwide use grams — not cups, not ounces. The reason is precision: a cup of flour can weigh anywhere from 120 g to 160 g depending on how tightly it is packed. A gram is always a gram. European and most international baking recipes use grams exclusively. Here are the most important baking conversions:
| Ingredient | 1 cup (US) | In grams | In ounces |
|---|---|---|---|
| All-purpose flour | 1 cup | 125 g | 4.4 oz |
| Bread flour | 1 cup | 130 g | 4.6 oz |
| Cake flour | 1 cup | 100 g | 3.5 oz |
| Granulated sugar | 1 cup | 200 g | 7.1 oz |
| Brown sugar (packed) | 1 cup | 220 g | 7.8 oz |
| Powdered sugar | 1 cup | 120 g | 4.2 oz |
| Butter | 1 cup (2 sticks) | 227 g | 8 oz |
| Butter | 1 tablespoon | 14.2 g | 0.5 oz |
| Vegetable oil | 1 cup | 218 g | 7.7 oz |
| Honey | 1 cup | 340 g | 12 oz |
| Salt | 1 teaspoon | 6 g | 0.2 oz |
| Baking powder | 1 teaspoon | 4 g | 0.14 oz |
| Cocoa powder | 1 cup | 85 g | 3 oz |
| Rolled oats | 1 cup | 90 g | 3.2 oz |
| Chocolate chips | 1 cup | 170 g | 6 oz |
Troy Ounce: Gold, Silver and Precious Metals
When you buy gold, silver, platinum or palladium, prices are quoted in troy ounces — not regular avoirdupois ounces. A troy ounce is heavier: 31.1035 grams vs 28.3495 grams for a regular ounce. The difference of about 10% matters enormously when calculating precious metal values.
1 troy oz = 31.1035 grams
1 regular oz = 28.3495 grams
| Troy Ounces | Grams | Context |
|---|---|---|
| 0.1 troy oz | 3.11 g | Small gold coin fragment |
| 0.5 troy oz | 15.55 g | Small silver round |
| 1 troy oz | 31.10 g | Standard gold/silver coin (American Eagle, Maple Leaf) |
| 2 troy oz | 62.21 g | 2-oz silver coin (popular collectible) |
| 5 troy oz | 155.5 g | 5-oz silver bar |
| 10 troy oz | 311.0 g | 10-oz silver bar |
| 1 troy pound (12 oz) | 373.2 g | Troy pound (not the same as regular pound) |
| 32.15 troy oz | 1000 g | 1 kilogram gold bar |
| 400 troy oz | 12,441 g | Standard London Good Delivery gold bar |
When a dealer quotes gold at "$2,400 per troy ounce" and you want to know the price per gram, divide by 31.1035: $2,400 ÷ 31.1035 = $77.16 per gram. Going the other way: if a European dealer quotes €72 per gram, multiply by 31.1035 to get €2,239 per troy ounce.
Shipping Weights: Ounces, Grams and Kilograms
USPS, UPS, and FedEx domestic rates use pounds and ounces. International shipping uses kilograms. Here are the weight thresholds that matter most for shipping costs:
| Ounces | Grams | Kilograms | Shipping Context |
|---|---|---|---|
| 1 oz | 28.3 g | 0.028 kg | Greeting card / standard letter |
| 3.5 oz | 100 g | 0.1 kg | USPS first-class letter max |
| 8 oz | 227 g | 0.227 kg | Small package (paperback book) |
| 16 oz | 454 g | 0.454 kg | 1 lb — most e-commerce threshold |
| 35 oz | 1000 g | 1 kg | International flat rate threshold |
| 70 oz | 2000 g | 2 kg | Small parcel limit some carriers |
| 176 oz | 5000 g | 5 kg | Medium parcel pricing tier |
| 352 oz | 9979 g | 9.98 kg | Under 10 kg threshold (international) |
| 706 oz | 20,000 g | 20 kg | Freight threshold many carriers |
Food Labels: US oz vs Metric g
US food packaging is required to show both ounces and grams. But when you shop internationally — on Amazon marketplace, iHerb, or foreign grocery sites — you may only see grams. Here are common food package sizes translated:
- 100 g = 3.53 oz — European standard serving size on nutrition labels
- 200 g = 7.05 oz — typical European yogurt container
- 250 g = 8.82 oz — European butter block (≈ 2 US sticks)
- 454 g = 16 oz — exactly 1 pound; common US ground beef package
- 500 g = 17.6 oz — standard European pasta package
- 1 kg = 35.27 oz = 2.205 lbs — standard European flour, sugar bag
Convert Any Weight Instantly
For any weight conversion — ounces, grams, pounds, kilograms, troy ounces — use the ConvertProf Weight Converter. Exact factors, no rounding, works offline in your browser.