Convert oz to g instantly.
Ounces to Grams Converter
Standard, troy & fluid oz — UK & US
💡 Type in either box, enter grams to get ounces, or ounces to get grams instantly.
| Ounces | Grams (exact) | Rounded (baking) |
|---|
"Rounded" values are the figures most UK recipe books use for convenience. For precise scientific or jewellery work, use the exact converter above with Troy oz selected where relevant.
I still remember the first time I tried to bake a Victorian sponge from an old British cookbook while living out of a flat that only had a US kitchen scale. Four ounces of butter, the recipe said. Four ounces of what, exactly — the same ounces I'd use to weigh a gold ring, or the same ounces printed on a bottle of milk? Turns out, no. There are three completely different "ounces" floating around in English, and mixing them up is exactly how a cake ends up dense as a doorstop.
That mix-up is the whole reason the calculator above exists. It doesn't just do one conversion — it does all three, switches between UK and US conventions, and shows you the working so you're never just trusting a black box. Below, I'll walk through exactly how to use every part of it, plus the full conversion tables and the "why" behind numbers that don't quite match what you might have seen elsewhere.
The Three Ounces Nobody Warns You About
Here's the bit most conversion charts skip over: when someone says "ounce," they could mean one of three genuinely different things, and only one of them is really about weighing flour.
- Standard (avoirdupois) ounce — the one you actually want for cooking and baking. 1 oz = 28.349523125 g, exactly. This is the everyday ounce printed on butter wrappers, bags of sugar, and recipe cards.
- Troy ounce — used exclusively for precious metals: gold, silver, platinum. It's heavier than a standard ounce at 31.1034768 g, which is exactly why a "1 oz gold coin" weighs noticeably more than "1 oz of chocolate."
- Fluid ounce — not a weight at all. It's a measure of volume, and worse, the UK and US disagree on how big it is: a UK (Imperial) fluid ounce is 28.4130625 ml, while a US fluid ounce is 29.5735295625 ml — about 4% bigger.
So if you've ever wondered why one website tells you a troy ounce to grams conversion gives a bigger number than a normal ounce, or why an American recipe's "8 fl oz" doesn't quite match a British one, this is the entire explanation. It isn't a typo anywhere — it's genuinely three different systems wearing the same name.
How to Use This Ounces to Grams Converter
The calculator at the top of this page is built to handle all three ounce types in one place, switch between UK and US conventions, and stay accurate down to 15 decimal places if you ever need it. Here's what each part does.
Pick your ounce type
The three tabs at the top — Standard oz, Troy oz, and Fluid oz — switch the whole calculator's conversion factor. Baking or weighing food? Stay on Standard. Pricing gold or silver? Use Troy. Converting milk, oil or any liquid? Use Fluid.
Type into either box
Both the Ounces box and the Grams box work in real time and in both directions. Type a number of ounces and the grams update instantly; clear that and type grams instead, and the ounces box recalculates. You never have to press a "convert" button.
Use the Swap button for quick what-ifs
The circular arrow between the two boxes lets you take the number currently shown in grams and drop it straight into the ounces box, instantly recalculating — handy for quickly checking "what if this number were ounces instead?"
Set your Region — UK or US
This one matters more than it looks. It changes the fluid ounce conversion factor, the pint size used in the breakdown line (20 fl oz for a UK pint vs 16 fl oz for a US pint), and even the rounding style shown in the baking table further down. Leave it on UK for British recipes and switch to US for American ones.
Adjust Precision if you need more (or fewer) decimals
By default the result shows 4 decimal places, which is more than enough for baking. Scientific work, jewellery valuations or anything requiring extreme accuracy can push this all the way to 15 decimal places.
Read the breakdown line under each box
Underneath the ounces box you'll see a line like "= 2 lb 3 oz" (or "= 1 pt 4 fl oz" on the Fluid tab) — and under the grams box, "= 1 kg 250 g". These update live so you don't have to do the pounds/kilograms maths yourself.
Tap a quick preset
Common amounts — ¼ oz, ½ oz, 1 oz, 2 oz, 4 oz, 8 oz, 16 oz, 100 g, 250 g — sit as one-tap chips just below the calculator, so you don't need to type out the numbers you use most.
Check the Visual Weight bar
A simple, purely visual gauge that fills up as your gram value increases (up to 500 g), just to give you an intuitive sense of scale — useful when you're trying to picture how much 85 g of flour actually looks like next to 450 g.
Reset or Copy your result
Reset clears everything back to the default 1 oz and UK/Standard settings. Copy result puts a ready-to-paste line like "4 oz = 113.4 g" straight onto your clipboard — useful for pasting into a shopping list or recipe note.
Open the conversion chart at the bottom
The dashed box labelled "Common baking conversions" (or "gold & silver conversions" / "liquid conversions" depending on your tab) expands into a full reference table without leaving the page — the same tables we've reproduced below for anyone who prefers to scroll rather than click.
Ounces to Grams: The Full Conversion Table (UK & US)
This is the one people search for most: how many grams in an ounce, and what does that look like across a whole recipe's worth of quantities? The middle column below is the mathematically exact figure. The two "rounded" columns are not the same thing rounded twice — they're genuinely different, real-world conventions. The UK column follows the rounding used in Delia Smith's Complete Cookery Course and similar long-standing British references. The US column follows the nearest-whole-gram convention published by America's Test Kitchen / Cook's Illustrated.
| Ounces | Grams (exact) | UK rounded | US rounded |
|---|---|---|---|
| ¼ oz | 7.09 g | 5 g | 7 g |
| ½ oz | 14.17 g | 10 g | 14 g |
| 1 oz | 28.35 g | 25 g | 28 g |
| 2 oz | 56.70 g | 50 g | 57 g |
| 3 oz | 85.05 g | 75 g | 85 g |
| 4 oz | 113.40 g | 110 g | 113 g |
| 5 oz | 141.75 g | 150 g | 142 g |
| 6 oz | 170.10 g | 175 g | 170 g |
| 7 oz | 198.45 g | 200 g | 198 g |
| 8 oz | 226.80 g | 225 g | 227 g |
| 9 oz | 255.15 g | 250 g | 255 g |
| 10 oz | 283.50 g | 275 g | 283 g |
| 12 oz | 340.19 g | 350 g | 340 g |
| 16 oz (1 lb) | 453.59 g | 450 g | 454 g |
Troy Ounce to Grams: For Gold, Silver & Precious Metals
If you've ever compared an avoirdupois ounce vs a troy ounce and wondered why the numbers on a bullion dealer's site never quite match a cooking conversion chart, this is why: a troy ounce is fixed at exactly 31.1034768 grams, worldwide, with no UK/US variation at all — unlike the fluid ounce, gold and silver pricing uses one single global standard.
| Troy Ounces | Grams (exact) | Typical product |
|---|---|---|
| 1/20 oz | 1.56 g | Fractional gold coin |
| 1/10 oz | 3.11 g | Fractional gold coin |
| 1/4 oz | 7.78 g | Fractional gold coin |
| 1/2 oz | 15.55 g | Half-ounce coin |
| 1 oz | 31.10 g | Standard coin or bar |
| 2 oz | 62.21 g | Small bar |
| 5 oz | 155.52 g | Collector bar |
| 10 oz | 311.03 g | Investment bar |
| 100 oz | 3110.35 g | Large bullion bar |
Fluid Ounces to Grams: Why the UK and US Don't Agree
Fluid ounces measure volume, not weight, so strictly speaking there's no single "fluid ounce to grams" answer — it depends on the density of whatever you're measuring. What the table below (and the calculator above) actually gives you is the gram-equivalent assuming water-like density, which is a reasonable stand-in for milk, most stocks, and thin batters, but will be noticeably off for something like oil (lighter) or honey (heavier).
| Fl Oz | UK (ml & g, ≈water) | US (ml & g, ≈water) |
|---|---|---|
| 1 fl oz | 28.41 | 29.57 |
| 2 fl oz | 56.83 | 59.15 |
| 4 fl oz | 113.65 | 118.29 |
| 5 fl oz | 142.07 | 147.87 |
| 8 fl oz | 227.30 | 236.59 |
| 10 fl oz | 284.13 | 295.74 |
| 16 fl oz | 454.61 | 473.18 (1 US pint) |
| 20 fl oz | 568.26 (1 UK pint) | 591.47 |
Notice that a UK pint (20 fl oz) and a US pint (16 fl oz) aren't just different because of the fluid ounce size — they're different counts of fluid ounces too. That's a 20% gap in volume, not the roughly 4% gap you'd expect just from the ounce definitions alone, which is exactly the kind of thing that trips people up converting a British recipe for an American kitchen or vice versa.
Frequently Asked Questions
For everyday cooking and baking, one standard (avoirdupois) ounce equals 28.349523125 grams — usually written as 28.35 g, or rounded to 28 g for quick kitchen maths. This is the ounce used for weighing flour, sugar, butter, and pretty much any solid food ingredient.
Both figures show up because they come from two different traditions, not because one is wrong. Classic British cookbooks (Delia Smith among them) round 1 oz down to 25 g for tidy, easy-to-remember numbers. American references like America's Test Kitchen round to the nearest whole gram, giving 28 g — much closer to the true figure of 28.35 g. Our calculator's Region toggle switches between the two automatically.
A standard (avoirdupois) ounce is the everyday weight unit used for food, post, and general shopping — 28.35 g. A troy ounce is reserved for precious metals like gold and silver and weighs more, at 31.10 g. Mixing the two up when pricing metal is a genuinely common and costly mistake.
No. A UK (Imperial) fluid ounce is 28.41 ml, while a US fluid ounce is 29.57 ml — about 4% larger. It gets more noticeable at the pint level: a UK pint is 20 fl oz (568 ml) while a US pint is only 16 fl oz (473 ml), a 20% difference in actual volume.
Only approximately, and only if you know the density of what you're measuring. Fluid ounces measure volume; grams measure weight. For water, milk, or similarly water-like liquids, 1 ml is close enough to 1 g that the numbers line up. For oil, honey, syrup, or anything noticeably lighter or heavier than water, the true weight will differ from the volume-based figure.
Most online converters only handle one rounding convention, or don't distinguish between avoirdupois, troy and fluid ounces at all. Since UK and US cookbooks each have their own long-established (and different) rounding traditions, two "correct" charts can legitimately show different rounded numbers for the same exact weight.
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