Last reviewed: 7 May 2026
4 oz by weight = 113 g. (Avoirdupois ounces, the kind on packets and meat labels.)
4 fl oz by volume = 114 ml in the UK, 118 ml in a US recipe. Same name, different sizes — the gap matters in baking.
If you've landed here, you're probably mid-recipe with an American measurement on screen and a British kitchen scale on the counter. The short version is above. The rest of this page tells you what 4 oz actually looks like for the ingredients UK shoppers buy, and why this question keeps coming up in the first place.
Britain has been on grams for prepacked food since the 1990s. Nutrition information on UK labels is required to be in grams or millilitres under retained Regulation (EU) No 1169/2011, and most home cookbooks have followed the same logic for a long time. So where does "4 oz" still come from?
The single biggest source of confusion. "4 oz" and "4 fl oz" are not the same measurement.
If a recipe says "4 oz chicken", that's weight — put 113 g of raw chicken on the scale. If it says "4 fl oz milk", that's volume — pour 114 to 118 ml depending on whose recipe it is. Coincidentally, water at room temperature has a density very close to 1 g per ml, which is why the same-looking number causes the mix-up. For everything denser or lighter than water (oil, syrup, flour) the two values diverge fast.
Imperial fluid ounces and US fluid ounces are different sizes. This is the bit nobody mentions.
For a glass of milk in your cereal, a 4 ml difference is invisible. For a pancake batter, a custard, or a meringue where ratios matter, it's enough to change the texture. If the recipe is American, treat 4 fl oz as 118 ml. If you're reading an old British cookbook, 114 ml. When in doubt, the recipe origin tells you which: domain ending in .com with cup measurements alongside fl oz is almost always US.
One more US-specific number worth knowing: 1 US cup = 8 fl oz US ≈ 237 ml. So "4 fl oz" in a US recipe is exactly half a US cup.
This is the part conversion charts skip. 113 g is an abstract number until you see it next to something real you've bought.
113 g is roughly half of a small breast or a third of a large one. Tesco and Sainsbury's value-pack breasts often run 150–200 g each; a 4-oz portion is smaller than a single one. If a US recipe wants four 4-oz breasts, you're looking at four small ones or two large ones halved.
A standard UK pack of mince is 500 g. 113 g is about one fifth of the pack — close to a single burger patty. The Quarter Pounder is exactly this weight.
UK supermarket salmon fillets typically run 110–130 g each. One small fillet is almost exactly 4 oz. A "4 oz salmon" call-out in a US recipe is a single UK supermarket portion.
113 g is about a quarter of a 454 g block (the standard 1 lb Cathedral City / supermarket-own block). It's a generous helping for a sandwich — three or four typical cheese portions.
UK butter is sold in 250 g blocks. 113 g is just under half a block. A US recipe written for "1 stick" of butter (113 g, the American unit) maps cleanly onto half a UK block, give or take a few grams.
113 g of dry pasta is a generous single portion. NHS Eatwell Guide portion advice for dry pasta is around 75–85 g per person uncooked, so 4 oz is a hungry-adult serving rather than a child's. A 500 g pack contains roughly four and a half such portions.
Same story: 113 g of uncooked rice is a generous single portion. NHS Eatwell suggests around 75 g uncooked per adult. A US recipe asking for 4 oz of rice per person is a larger portion than UK guidance assumes.
An NHS porridge serving is about 40 g uncooked. 113 g is roughly two and a half porridge servings, or one large breakfast for two.
Single yoghurt pots in UK supermarkets are typically 125 g. 113 g is just under a single pot. Close enough that "a pot" works as a substitute in most recipes.
The pattern: 4 oz / 113 g sits between "a single serving" and "a generous serving" for most proteins and starches sold in the UK. It's not a coincidence — it maps closely to the US restaurant convention of a "4-oz portion" of meat or fish, which is how a lot of recipes ended up using the number.
If you flip over any UK packet, the nutrition panel is in grams per 100 g and grams per portion. That's not a stylistic choice — it's the law. Retained Regulation (EU) No 1169/2011 (the Food Information for Consumers regulation) requires the mandatory net quantity on prepacked food to be expressed in metric units. Imperial weights can appear alongside but cannot be the primary unit.
For nutrition tracking, this is genuinely useful. Per-100 g figures scale linearly: if your label says 165 kcal per 100 g and you ate 113 g, the maths is 165 × 1.13 = 186 kcal. There's no per-ounce reckoning to do, no fluid-vs-weight to disentangle. The label and your scale already agree.
| Ounces (oz) | Grams (g) |
|---|---|
| 1 oz | 28 g |
| 2 oz | 57 g |
| 3 oz | 85 g |
| 4 oz | 113 g |
| 5 oz | 142 g |
| 6 oz | 170 g |
| 8 oz | 227 g |
| 16 oz (1 lb) | 454 g |
| Imperial fl oz | Millilitres (ml) |
|---|---|
| 1 fl oz UK | 28 ml |
| 2 fl oz UK | 57 ml |
| 4 fl oz UK | 114 ml |
| 8 fl oz UK | 227 ml |
| 10 fl oz UK | 284 ml (½ pint) |
| 20 fl oz UK | 568 ml (1 pint) |
| US fl oz | Millilitres (ml) |
|---|---|
| 1 fl oz US | 30 ml |
| 2 fl oz US | 59 ml |
| 4 fl oz US (½ cup) | 118 ml |
| 8 fl oz US (1 cup) | 237 ml |
| 16 fl oz US (1 US pint) | 473 ml |
No. 4 oz by weight is 113 g. 4 fl oz by volume is 114 ml (UK) or 118 ml (US). The numbers happen to look similar because water has a density of 1 g per ml — so 4 fl oz of water weighs almost exactly 4 oz. For anything that isn't water, the two diverge.
113 g raw — about half a small UK supermarket breast, or a third of a large one. After cooking it loses around a quarter of its weight to water, so cooked weight is closer to 85 g.
4 fl oz is half a US cup (118 ml). UK recipes don't measure in cups by convention. If you only have a US measuring cup, half-fill it for "4 fl oz".
A quarter pound is 4 oz — so 113 g. The Quarter Pounder is named after this weight.
If liquid is also given in cups, it's US. If the rest of the book uses grams and pints, it's UK. The 4 ml gap between 114 ml UK and 118 ml US doesn't matter for soups and sauces but does matter for cake and custard ratios. American recipes are by far the more common source of "4 oz" searches.
We built our app to skip this conversion step entirely for British shoppers. Scan a UK barcode with NutraSafe and the calorie and macro figures come straight off the pack's nutrition label — already in grams, already in the unit your kitchen scale uses. No oz-to-g maths, no UK-vs-US fluid ounce checks. If you log "113 g of chicken breast" the figures are exact, not estimated.
For US recipes we display gram weights for every food in the database, and our serving picker lets you choose by gram weight, by pack portion, or by typical kitchen units. The app handles the unit translation so the recipe maths stays in your head.
Scan any UK pack in NutraSafe and we show calories, macros and portion size straight from the label in grams. Free to log up to 25 foods/day · NutraSafe Pro £3.99/month for AI Coach, allergen warning detail and full reaction history.
Sources: avoirdupois ounce (NIST Handbook 44, 28.349523 g); imperial fluid ounce (UK Weights and Measures Act 1985, 28.4131 ml); US customary fluid ounce (NIST, 29.5735 ml); UK food labelling unit requirements (retained Regulation (EU) No 1169/2011, Annex IX); pasta and rice portion guidance (NHS Eatwell Guide).
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