What is an ounce, and what is a gram?
One ounce is 28.35 grams. Put a slice of cheese on a kitchen scale set to grams and it reads about 28. A US stick of butter reads 113. The Ounces to Grams Converter does that math for any amount: type ounces, get grams, with the full calculation shown underneath. It reads amounts the way labels and recipes print them, like 3 1/2 or ¾ oz. And it stops you when the "ounce" in front of you is a different unit.
The ounce
The ounce on a bag of coffee or a recipe card is the avoirdupois ounce, one sixteenth of a pound. A treaty sets its size, not a lump of metal in a vault. In 1959 the United States, the United Kingdom, Canada, Australia, New Zealand, and South Africa agreed that one pound equals exactly 0.45359237 kilograms. Divide that by 16 and one ounce comes out to exactly 28.349523125 grams. The US still uses ounces for everyday weight: deli counters, meat trays, postage, and most home recipes. Older British cookbooks use them too.
The gram
The gram is the metric unit of mass, one thousandth of a kilogram. Nearly every other country weighs food, mail, and medicine in grams. Nutrition labels everywhere, the US included, list protein, fat, and sugar in grams. A US nickel weighs 5 g. A paperclip weighs about 1 g. Because the pound is defined in kilograms, the ratio between the two units never drifts. Nobody measures it. It's 28.349523125, by definition, forever.
How ounces to grams conversion works
There are 28.349523125 grams in an ounce, so it's one multiplication. No offset, no second step, no lookup table.
grams = ounces × 28.349523125
For kitchen work, 28.35 is plenty. It stays within half a gram of the exact answer until you pass 65 pounds.
Here's a real case. A brownie recipe calls for 3 1/2 oz of dark chocolate, 6 oz of butter, and 10 oz of sugar. Your scale reads grams.
- Type
3 1/2and the converter shows 3.5 oz × 28.349523125 = 99.22 g - 6 oz × 28.349523125 = 170.1 g
- 10 oz × 28.349523125 = 283.5 g
Your scale reads whole grams, so weigh 99 g, 170 g, and 284 g. Done. You didn't have to turn 3 1/2 into 3.5 first. The converter reads mixed numbers, fraction symbols like ½, and a trailing "oz" or "ounces."
No calculator nearby? Multiply by 28, then add a third of the ounce number. For 6 oz that's 168 + 2 = 170 g. For 12 oz it's 336 + 4 = 340 g, against an exact 340.19 g. That trick is off by less than a tenth of a percent. Multiplying by plain 28 is the one to avoid. It loses 0.35 g per ounce, which is 11 g on a 2 lb bag.
Going the other way, divide grams by 28.35, or use the grams to ounces converter.
Common ounces to grams conversions
These are the oz to g amounts people search for most, matched to where you actually see them. Every gram value comes straight from the tool.
| Ounces | Grams | Where you'll see it |
|---|---|---|
| ¼ oz | 7.09 g | A packet of active dry yeast |
| ½ oz | 14.17 g | A tablespoon of butter |
| 1 oz | 28.35 g | A single-serve bag of chips |
| 2 oz | 56.7 g | One serving of dry pasta |
| 3.5 oz | 99.22 g | A 100 g chocolate bar with a US label |
| 4 oz | 113.4 g | A stick of butter, a quarter-pound burger patty |
| 8 oz | 226.8 g | Half a pound, a brick of cream cheese |
| 12 oz | 340.19 g | A bag of coffee or chocolate chips |
| 14.5 oz | 411.07 g | A can of diced tomatoes |
| 16 oz | 453.59 g | One pound, a box of dry pasta |
| 28 oz | 793.79 g | A large can of crushed tomatoes |
| 32 oz | 907.18 g | Two pounds, a bag of brown sugar |
| 80 oz | 2,267.96 g | A 5 lb bag of flour |
Look at a can of tomatoes and you'll find both numbers printed: "NET WT 14.5 OZ (411 g)." US law requires most packaged food to show both units. Manufacturers round the grams to a whole number, which is why the label and this page agree to the gram.
Some odd ounce sizes are really round metric sizes in disguise. A 3.5 oz chocolate bar is a 100 g bar. A 5.3 oz yogurt cup is 150.25 g, made as a 150 g cup. A 7 oz jar is 198.45 g, made as 200 g. If a US package lists a strange decimal in ounces, check the grams. There's usually a round number hiding there.
Results show two decimal places for anything a gram or heavier. That's already finer than a kitchen scale, which reads to 1 g, or a postal scale, which reads to about 0.1 oz. Under a gram, it shows up to four decimals, so 0.001 oz reads 0.0283 g.
When you'll need to convert oz to g
Baking from a US recipe on a metric scale. US recipes list chocolate, butter, cheese, and meat in ounces. A scale set to grams reads to the gram, while most scales set to ounces jump in tenths or eighths. Convert once, weigh in grams, and the batch comes out the same every time.
Cooking a metric recipe with US packages. A recipe wants 400 g of tomatoes, and your store sells 14.5 oz cans. That's 411.07 g, close enough to use one can. A recipe asking for 225 g of cream cheese? One 8 oz brick is 226.8 g.
Tracking what you eat. Nutrition labels list serving sizes in grams, but a butcher's label says 12 oz. If you portion by weight, oz to g is the step between the package and the log.
Shipping a package. US carriers price light parcels by the ounce. Customs forms and international carriers want grams. A 12 oz parcel goes on the form as 340.19 g.
None of this should need a subscription. Some recipe and meal-planning apps put the metric switch behind a premium plan, and the plan starts with a 7-day trial that wants a card number first. Others bundle an AI assistant into a monthly price and call it a kitchen feature. Multiplying by 28.35 isn't a feature. It's arithmetic. This page is the whole tool: no account, no trial, no upgrade screen between you and the number. It works the same for a line cook, a student in a dorm kitchen, and someone shipping a birthday gift across the border.
Edge cases and gotchas
Fluid ounces are not ounces. An ounce (oz) measures weight. A fluid ounce (fl oz) measures volume, about 29.57 mL in the US. One fluid ounce of water weighs about 29.57 g, but a fluid ounce of honey weighs about 42 g. Type "8 fl oz" and the converter tells you why it can't answer, instead of guessing.
Troy ounces are heavier. Gold, silver, and platinum are priced per troy ounce, which is 31.1034768 g, about 10% heavier than the everyday ounce. A one-ounce gold coin weighs 31.1 g, not 28.35 g. Type "2 ozt" and you get a message with the correct figure: 2 ozt is 62.21 g.
Pounds and ounces together. A roast labeled 2 lb 6 oz needs one number. Type it as printed and the converter answers "2 lb 6 oz is 38 oz — type that." 38 oz is 1,077.28 g. Type "1.5 lb" and it tells you that's 24 oz.
Commas. The converter treats "1,200" as twelve hundred ounces, which is 34,019.43 g. A decimal comma like "1,5" gets a prompt to use a dot instead, so a European-style decimal never turns into 15.
Limits. Negative amounts get a short explanation instead of a result. The ceiling is one trillion ounces, roughly 28 million tonnes. Anything larger gets a message, never a broken number.
Related converters
Ounces to grams is one slice of a bigger kitchen-and-shipping problem. These tools cover the rest:
- Grams to Ounces for the reverse, when a metric recipe meets a US scale.
- Ounces to Pounds when a pile of ounces needs to become a shipping weight.
- Cups to Grams for recipes written in cups, where the grams depend on the ingredient.
- Tablespoon to Grams for small amounts of butter, sugar, and spices.
- Oz to Cups for fluid ounces, which measure volume.
- lbs to kg and the full Weight Converter for body weight and bigger loads.
Frequently asked questions
How many grams are in an ounce?
Exactly 28.349523125 grams. Round it to 28.35 for cooking. That figure is a definition, not a measurement: one pound is 453.59237 grams by international agreement, and an ounce is a sixteenth of a pound. Numbers like 28.3 or 28 are rounded versions of the same value.
How many grams is 8 oz?
8 oz is 226.8 grams, which is half a pound. The other common amounts: 4 oz is 113.4 g, 12 oz is 340.19 g, and 16 oz is 453.59 g. Type any amount into the Ounces to Grams Converter for the exact figure.
Is an ounce 28 grams or 30 grams?
Neither, exactly, but 28 is much closer. Some translated recipes round an ounce to 30 g to keep the math easy. That's 6% heavy: a pound comes out as 480 g instead of 453.59 g. For baking, use 28.35.
Are fluid ounces the same as ounces?
No. Ounces measure weight, and fluid ounces measure volume. They only match for water, where 1 fl oz weighs about 29.57 g. If a recipe says "8 oz milk," it almost always means a measuring cup, not a scale. For liquids, use the oz to cups converter.
How do I convert pounds and ounces to grams?
Turn the whole weight into ounces first. Multiply the pounds by 16 and add the ounces, then multiply by 28.35. For 2 lb 6 oz: 32 + 6 = 38 oz, and 38 oz is 1,077.28 g. If you type "2 lb 6 oz" into the converter, it does the first step for you and tells you to enter 38.
Does the converter save or send what I type?
No. The conversion runs in your browser. Nothing goes to a server, and there's no account to create. Close the tab and the numbers are gone.