You're halfway through a recipe. Or maybe you're tracking macros and the nutrition label lists ounces but your app wants grams. The ingredient list says "4 oz cream cheese" and your kitchen scale only does grams. Either way, you're standing there, phone in hand, wondering: how many grams is 4 oz, exactly?
The short answer: 113.4 grams.
But if you cook, bake, meal prep, or deal with international recipes often enough, the short answer isn't always enough. Because ounces aren't always ounces. And grams don't lie — but your measuring cup might.
Let's unpack this properly.
What Is an Ounce, Really
Most people use "ounce" like it's a single, universal unit. It's not.
There are two completely different things called an ounce, and confusing them is the fastest way to ruin a batch of macarons.
The avoirdupois ounce (weight)
Basically what you mean 95% of the time. It's a unit of mass (colloquially, weight). One avoirdupois ounce = 28.349523125 grams. That's the standard conversion.
So 4 oz × 28.3495 = 113.Which means 398 grams. Round to 113.4 and you're fine for almost anything.
The fluid ounce (volume)
Here's where it gets messy. Practically speaking, 4. But — and this is critical — 4 fluid ounces of water weighs about 118 grams, not 113.A fluid ounce measures volume, not weight. One US fluid ounce = 29.5735 milliliters. Because water's density is ~1 g/ml.
But 4 fluid ounces of honey? On top of that, that's ~170 grams. 4 fluid ounces of olive oil? So ~109 grams. But the volume is the same. The weight is not.
If a recipe says "4 oz" without specifying "fl oz" or "fluid," assume weight. But if it's a liquid ingredient in a US recipe written in cups/tablespoons, there's a decent chance they mean fluid ounces. Context matters.
The troy ounce (precious metals)
You'll probably never encounter this in a kitchen. Because of that, if you're weighing bullion, use this. One troy ounce = 31.It's used for gold, silver, platinum. That's why 1035 grams. If you're weighing flour, don't.
Why This Conversion Actually Matters
You might think: close enough is fine.Sure. Because of that, toss in 110g or 120g of onions instead of 113. Consider this: * And for a stew? 4g — nobody notices.
But baking is chemistry. Not metaphorically. Literally.
The flour trap
A cup of all-purpose flour weighs anywhere from 120g to 145g depending on how you scoop it. ~145g. Two cups? Because of that, dip and sweep? In real terms, ~125g. Spoon and level? That's a 20g swing per cup. You could be off by 40g — more than a third of your 4 oz target.
This is why professional bakers always weigh. Grams don't care how you scooped.
Nutrition tracking
If you're logging food, 4 oz of chicken breast = 113.4g raw. But cooked? Even so, that same piece loses ~25% water weight. Now it's ~85g. Plus, if you log the raw weight as cooked, your protein numbers are inflated. If you log cooked as raw, you're undercounting.
The label says "4 oz (113g)" — that's almost always raw weight unless specified otherwise.
International recipes
European recipes use grams. Australian recipes use grams. In real terms, canadian recipes mostly* use grams but sometimes cups. In practice, uS recipes? Cups, ounces, pounds, sticks, pinches, dashes — chaos.
Converting 4 oz to grams lets you actually follow a British bake-off technical challenge without guessing.
How to Convert (And When Not To)
The math you can do in your head
Quick rule: 1 oz ≈ 28.35g. So:
- 1 oz → 28g
- 2 oz → 57g
- 3 oz → 85g
- 4 oz → 113g
- 8 oz (½ lb) → 227g
- 16 oz (1 lb) → 454g
Need more precision? 3495. But honestly? Practically speaking, multiply ounces by 28. And 28. 35 is fine for food.
When to just use a scale
Always. Seriously.
A $15 digital kitchen scale does grams and ounces. Still, tare the bowl. Plus, add ingredient. Done. Worth adding: no conversion needed. No "wait, is this packed brown sugar or loose?" ambiguity.
For more on this topic, read our article on 15 out of 20 as a percentage or check out how many years is a billion seconds.
If you don't have one, get one. It's the single most useful tool in a kitchen after a knife.
When volume-to-weight charts help
Sometimes you can't* weigh. You're at a friend's house. The scale died. You're camping. Fine.
But never trust a generic "1 cup = X grams" chart for anything that compresses. Flour, powdered sugar, brown sugar, cocoa, shredded cheese — these vary wildly.
Better: look up the specific ingredient on the USDA FoodData Central database. On top of that, or the King Arthur Flour ingredient weight chart. Which means or the recipe developer's own notes. They tested it. Trust their numbers over a generic table.
Common Mistakes People Make
Treating fluid ounces and weight ounces as interchangeable
This is the big one. Because of that, 4 fl oz ≠ 4 oz wt. Not for water, not for anything.
- 4 fl oz water = 118g
- 4 fl oz milk = ~122g
- 4 fl oz heavy cream = ~119g
- 4 fl oz honey = ~170g
- 4 fl oz oil = ~109g
If a recipe says "4 oz milk" and you pour 4 fl oz (½ cup), you're close — ~122g vs 113g. But "4 oz honey" measured as 4 fl oz gives you 50% more honey by weight. That changes sweetness, moisture, browning, everything.
Rounding too early
113.398 rounds to 113.4. Fine. But if you're scaling a recipe ×20 for a bakery batch, that 0.398g × 80 oz = 31.8g error. Not nothing.
Carry decimals until the final step. In practice, your scale probably only reads to 0. 1g or 1g anyway — but don't compound rounding errors.
Assuming "4 oz" on a package means 113.4g net weight
Check the fine print. "Net wt 4 oz (113g)" — okay, they rounded. But some packages list drained weight for canned goods. A 4 oz can of mushrooms might only have 2.
meat. Always check whether the number accounts for water loss.
Ignoring ingredient temperature and form
Room-temperature butter weighs differently than cold butter. Fluffed-up powdered sugar weighs less than packed brown sugar. Frozen grated coconut weighs more than thawed.
These differences matter in precise baking. If a recipe assumes room-temp ingredients, working with straight-from-the-fridge items throws off your conversions.
Why This Matters Beyond Baking
Professional kitchens standardize on grams because consistency equals profitability. 4g gets identical results every time. Trying to eyeball "about 4 oz" from a stick of butter? A French pâtissier scaling macarons to 113.Good luck.
Home cooks benefit too—especially when adapting recipes across cuisines or scaling favorites for parties. In real terms, that chocolate cake you make with 8 oz cocoa powder? Doubling it becomes a math problem without consistent units.
Even meal planners tracking macros appreciate grams—they’re precise, universal, and easier to log than "1 cup shredded cheese" (which varies by grate size, compression, brand).
Practical Tips for Daily Cooking
- Bookmark a conversion calculator. Save it on your phone. Use it liberally.
- Invest in a scale that toggles between units. $20 models last decades.
- Learn the 28.35g/oz rule cold. Memorize key weights (4 oz = 113g, etc.).
- Keep a notebook. Jot down actual weights of ingredients you measure repeatedly—your go-to brown sugar, that dense feta, your grandmother’s flaky pastry flour.
- Trust the recipe author. If they give both metric and imperial, follow the weight measurements. Volume is approximate; weight is exact.
Final Thoughts
Cooking is science, art, and instinct—but it shouldn’t require arithmetic gymnastics mid-recipe. Understanding ounce-to-gram conversions removes friction between you and the food you’re creating.
Whether you're tackling a Swiss meringue or whipping up boxed-mix muffins, speaking the language of mass makes every dish turn out closer to intention. And isn’t that what cooking’s really about?
Now go forth—and measure confidently.
