How Many Grams Are in an Ounce?
Quick Answer: 28.35 grams in 1 ounce · 1/16 lb · 28.3495 g (exact)
At a glance
- 1 avoirdupois ounce = 28.35 g (the everyday ounce — food, cooking, body weight, postage)
- 1 troy ounce = 31.10 g (precious metals — gold, silver, platinum; ~10% heavier)
- 100 g = 3.53 oz (a clean metric anchor — chocolate-bar-sized portion)
An ounce holds 28.35 grams — that\'s the avoirdupois ounce, the one on your kitchen scale and in US recipes. It\'s a cross-system conversion (US customary → metric) that shows up in baking, meal prep, grocery math, and any American recipe you try to cook in Europe. The 28.35 value is a real international standard, exact to 28.349523125 g since 1959. There\'s one big exception: gold, silver, and other precious metals use the troy ounce (31.10 g) — a different system that kept the older 12-oz-per-pound structure. So "an ounce of gold" weighs about 10% more than "an ounce of beef". The rest of this page is mostly about the avoirdupois 28.35 g conversion — the one most people need.
What does an ounce look like in grams?
ounce → gram Quick Converter
Need more features? Try our complete ounce to gram converter.
1 ounce on the gram scale
1 oz = 28.35 g
The 28.35 number — what it actually represents
This is a cross-system conversion, meaning it bridges two different measurement systems that weren\'t designed to talk to each other. The ounce comes from old English/Roman units; the gram comes from the French metric system (1790s). When they had to be aligned in 1959 (international yard-and-pound agreement), the ounce was defined as exactly 28.349523125 grams. For anything below lab precision, 28.35 g is close enough (0.0007% off).
- The exact number — 28.349523125 g. Has 10 digits because it had to preserve the older avoirdupois pound (7000 grains) and the older international gram, simultaneously. It\'s not a round number, nor a simple fraction.
- The working number — 28.35 g. Three significant figures, 0.0007% error. This is what every kitchen scale, recipe chart, and nutrition label uses.
- The lazy number — 28 g. 1.2% off. You\'ll see this on some food blogs and in rough conversions, but it\'s bad enough to cause problems in baking — a 1-lb recipe multiplied through as "16 × 28" gives 448 g instead of the correct 454 g, a 6 g gap. For baking at home, use 28.35.
Outside the kitchen: jewelers and bullion dealers use the troy ounce (31.10 g). That\'s a separate system with a separate history, covered below. If you\'re weighing food, don\'t think about troy — it\'s not relevant.
Common kitchen portions in ounces and grams
The portions below are the ones that show up constantly in US recipes. If you cook from American cookbooks but use a metric kitchen scale (common for European cooks), this is the table you\'ll refer to most.
| Ounces | Grams | Common kitchen reference |
|---|---|---|
| ½ oz | 14.2 g | A tablespoon of butter; a large spice measure |
| 1 oz | 28.35 g | A standard nutrition-label serving size |
| 2 oz | 56.7 g | An espresso double shot by weight; a small portion |
| 3 oz | 85.0 g | A palm-sized portion of grilled chicken |
| 4 oz | 113.4 g | A quarter pound — one burger patty, one cheese block |
| 5 oz | 141.7 g | A single-serving fish fillet |
| 6 oz | 170.1 g | A dinner-portion chicken breast |
| 8 oz | 226.8 g | Half a pound — classic steak weight |
| 12 oz | 340.2 g | ¾ pound — a small roast or large boneless cut |
| 16 oz (1 lb) | 453.6 g | A full pound — a packed 1-lb bag of flour |
For scaling any recipe: ounces × 28.35 = grams. Grams ÷ 28.35 = ounces. The 0.4% error from using 28.35 instead of 28.349523125 is smaller than the precision of any kitchen scale, so this is the right working number.
Metric reference amounts in ounces
For the other direction — you have a recipe in grams and want US-style kitchen measurements:
- 50 g = 1.76 oz (half a stick of butter, roughly)
- 100 g = 3.53 oz (the classic European recipe amount — a chocolate bar)
- 150 g = 5.29 oz (common pasta portion per person)
- 200 g = 7.05 oz (medium chicken breast)
- 250 g = 8.82 oz (just over ½ lb)
- 500 g = 17.64 oz (just over 1 lb; a standard European package size)
- 1000 g = 1 kg = 35.27 oz (≈ 2.2 lb — the metric weight unit most people recognize)
Did you know?
The avoirdupois ounce was originally defined as 437.5 grains — a grain being a unit of mass based, literally, on the weight of a single grain of barley. The grain is still a legal unit of mass in the US and UK today (used in ballistics for bullet weight, and in pharmacy for drug dosing). 7,000 grains make an avoirdupois pound, 480 grains make a troy ounce (hence troy has the heavier ounce), and 24 grains make a pennyweight. When the metric system was imposed in Revolutionary France (1790s), the gram was defined as the mass of one cubic centimeter of pure water at 4°C — a physical reference entirely disconnected from barley grains. The two systems had to be reconciled in 1959, and the exact 28.349523125 g value is what makes the math land: 7,000 × (28.349523125 ÷ 437.5) = 453.59237 g per pound, consistent across all the old grain-based units.
How many grams are in an ounce of gold?
31.10 g — because gold is always priced in troy ounces, not avoirdupois. That 10% difference matters a lot when gold trades around $2,500/oz: the extra 2.75 g per ounce represents about $275 of metal.
Precious-metal markets globally (London, New York, Tokyo, Zurich) quote gold, silver, platinum, and palladium in US dollars per troy ounce. A "1-ounce gold coin" (American Gold Eagle, Canadian Maple Leaf, Krugerrand) contains exactly 31.1035 g of gold. Silver, platinum, palladium, and rhodium all follow the same convention.
Everything else — food, cosmetics, cannabis, groceries, postage — uses the avoirdupois 28.35 g ounce. The context tells you which system applies:
- Gold/silver coin, bullion, jewelry → troy ounce, 31.10 g
- Gemstones priced by weight (diamonds, etc.) → usually by carat, but bulk is troy
- Anything else → avoirdupois ounce, 28.35 g
If you\'re weighing gold scrap with a kitchen scale (measuring grams), multiply the gram total by 0.03215 to get troy ounces — not by 0.03527 (which is avoirdupois). Using the wrong conversion gives you a 10% error in the weight you\'d report to a dealer.
Complete ounce-to-gram reference
Gram values are NIST-exact, rounded to 1 decimal.
| Ounces | Grams (avoirdupois) | Grams (troy) | Common use |
|---|---|---|---|
| ⅛ oz | 3.5 | 3.9 | Small spice portion; cannabis eighth |
| ¼ oz | 7.1 | 7.8 | Cannabis quarter; a large pinch |
| ⅓ oz | 9.5 | 10.4 | Small portion of nuts or seeds |
| ½ oz | 14.2 | 15.6 | Tablespoon of butter; cannabis half |
| 1 oz | 28.3 | 31.1 | Nutrition-label serving |
| 2 oz | 56.7 | 62.2 | Small appetizer portion |
| 3 oz | 85.0 | 93.3 | Palm-size protein portion |
| 4 oz | 113.4 | 124.4 | Burger patty; ¼ pound |
| 5 oz | 141.7 | 155.5 | Fish fillet (single serving) |
| 6 oz | 170.1 | 186.6 | Dinner chicken breast |
| 8 oz | 226.8 | 248.8 | ½ pound; steak |
| 10 oz | 283.5 | 311.0 | Large portion or small roast |
| 12 oz | 340.2 | 373.2 | ¾ pound; common can/bottle size |
| 16 oz (1 lb) | 453.6 | 497.7 | Full pound; standard 1-lb bag |
Word order matters
- "How many grams in an ounce?" → 28.35 (avoirdupois — this page\'s main answer)
- "How many ounces in a gram?" → 0.0353 (1/28.35, very small)
- "How many grams in an ounce of gold?" → 31.10 (troy, because precious metals)
- "How many grams in a fluid ounce?" → depends on the liquid — a fluid ounce of water weighs ~29.57 g (close to 28.35 by coincidence), but a fluid ounce of oil weighs ~27 g, honey ~42 g.
The last bullet is the usual confusion — fluid ounce (volume, ~29.57 mL) and weight ounce (mass, 28.35 g) are close for water by coincidence but different for everything else.
The formula
grams = ounces × 28.3495 (avoirdupois, exact)
grams = troy ounces × 31.1035 (troy, exact)
The 28.349523125 g avoirdupois value was fixed in 1959 by the international yard-and-pound agreement; 31.1034768 g for the troy ounce was standardized by the UK Weights and Measures Act of 1878. Both are exact by definition, not approximations. For working with recipes and scales, 28.35 g is the right level of precision — more decimals add no useful accuracy in home cooking.
How to switch between ounces and grams in the kitchen
Using a digital kitchen scale
Nearly every digital kitchen scale has a Mode or Unit button that toggles between oz and g. Press it to switch — same weight, different display. For recipes that mix units (a common situation with American recipes cross-posted with European ones), leave the scale in grams and mentally convert the oz amounts using the 28.35 multiplier. Grams are finer than ounces for small amounts, which helps baking precision.
Quick mental math
For rough kitchen estimates: ounces × 30 gives grams +6% too high. For better precision without a calculator: ounces × 28 + ounces × 0.35 — the "28 times x, add a third of x" trick. Or memorize the common anchors: 4 oz = 113 g, 8 oz = 227 g, 16 oz = 454 g. Those three values cover most cooking.
When precision matters
For bread and pastry, work directly in grams — the gram is 28× finer than the ounce, so a scale in grams gives you much better resolution for hydration percentages and leavening ratios. Most serious baking blogs now publish recipes in grams first, with ounce conversions as a fallback. For stews, soups, and braises, ounces (or cups) are fine — small weight variations don\'t matter.
Frequently Asked Questions
How many grams are in an ounce?
28.35 grams in 1 avoirdupois ounce — the ounce used for everyday weight (food, meat, portions, body weight). Exact value: 28.349523125 g, fixed by international definition in 1959. For cooking purposes, 28.35 g is precise enough; some US conversion charts round to 28 g, which is off by 1.2%.
How many grams are in an ounce of gold?
Gold uses the troy ounce, not the avoirdupois ounce. 1 troy ounce = 31.10 grams (exact: 31.1034768 g). This is ~10% heavier than an avoirdupois ounce. When you see "$2,500 per ounce" for gold, silver, or platinum, it always means per troy ounce. A 1-ounce gold coin contains 31.10 g of metal, not 28.35 g.
How many grams are in 4 ounces?
113.4 grams (4 × 28.35 g). 4 oz is a quarter pound — the standard portion for a burger patty, a block of cheese, or a single-serving chocolate bar. Easy mental benchmark: 4 oz ≈ 113 g.
How many grams are in 8 ounces?
226.8 grams (8 × 28.35 g). 8 oz is a half pound — a common cut of beef, a deli-counter portion, or a quarter of a 2-lb roast. ≈ 227 g rounded.
How many ounces are in 100 grams?
3.53 ounces (100 ÷ 28.35). 100 g is a clean metric reference point — roughly 3.5 oz, or about a chocolate-bar-sized portion. Useful anchor for metric users converting to US recipes.
How many grams are in half an ounce?
14.17 grams (28.35 ÷ 2). A half ounce is a small kitchen portion — a tablespoon of butter, a shot of cheese, a single spice measure. For rough mental math, think "half ounce ≈ 14 g".
Is a gram of gold the same as a gram of feathers?
Yes — gram is a mass unit, so 1 g of gold and 1 g of feathers weigh exactly the same on a scale. They occupy very different volumes (gold is ~19× denser than feathers), but their mass is identical. The "ounce" distinction (troy vs avoirdupois) is about which ounce system you're in, not whether one gram weighs more than another.
How many grams are in 1 ounce of weed?
28.35 grams in an avoirdupois ounce — the standard cannabis measurement in legal US markets. Cannabis packaging typically uses "eighths" (⅛ oz = 3.5 g), "quarters" (¼ oz = 7.1 g), and "halves" (½ oz = 14.2 g) around this 28.35 g benchmark. Dispensary pricing is legally required to show weight in grams alongside ounces in most US states.
How do I convert ounces to grams quickly?
Multiply by 28.35. For quick kitchen estimates, multiply by 30 and subtract 5% — close enough for soup and sauce work. For baking, use 28.35 exactly (or use a digital scale that switches units). To go back, divide grams by 28.35.
Related Weight Conversions
- How many ounces in a pound? — 16 oz
- How many grams in a pound? — 453.59 g
- How many ounces in a cup? — 8 fl oz (volume)
- How many ounces in a tablespoon? — 0.5 fl oz (volume)
- How many mL in an ounce? — 29.57 mL (volume)
- Ounce to Gram full converter
- Gram to Ounce full converter
- Pound to Gram full converter
- Cooking Volume to Weight Converter — density-based
- Cooking Weight to Volume Converter — reverse
- All Cooking Measurement Tools
This page uses the avoirdupois ounce (28.349523125 g exact, 28.35 g in working form) as the default — the ounce used for everyday weight in the US and UK. The troy ounce (31.1034768 g exact, 31.10 g in working form) is covered where relevant to precious metals. Both are exact by international definition (avoirdupois: 1959 international yard-and-pound agreement; troy: UK Weights and Measures Act 1878). Conversions in tables round to 1 decimal place for readability.