To convert cup ounces to millilitres, multiply by 29.5735 for US fluid ounces or by 28.4131 for UK imperial fluid ounces. An 8 oz cup is about 237 ml, a 12 oz cup about 355 ml and a 16 oz cup about 473 ml using US ounces. The converter below works in both directions, and the tables underneath list the common cup sizes.
The result is the nominal volume for the size name. The real brim-full capacity of a paper cup is usually higher and varies by maker, which is covered in our guide to paper cup sizes.
How many ml is an 8 oz, 12 oz or 16 oz paper cup?
On the US fluid ounce, an 8 oz cup is 237 ml, a 12 oz cup is 355 ml and a 16 oz cup is 473 ml. Those are nominal figures for the size label. On the UK imperial fluid ounce the same names give 227 ml, 341 ml and 455 ml.
Oz to ml conversion table for paper cups
| Cup size (oz) | US fl oz: ml | UK fl oz: ml | Difference (ml) |
|---|---|---|---|
| 2.5 | 74 | 71 | 3 |
| 3 | 89 | 85 | 4 |
| 4 | 118 | 114 | 4 |
| 6 | 177 | 170 | 7 |
| 7 | 207 | 199 | 8 |
| 8 | 237 | 227 | 10 |
| 10 | 296 | 284 | 12 |
| 12 | 355 | 341 | 14 |
| 14 | 414 | 398 | 16 |
| 16 | 473 | 455 | 18 |
| 20 | 591 | 568 | 23 |
| 22 | 651 | 625 | 26 |
| 24 | 710 | 682 | 28 |
Millilitres are rounded to the nearest whole number before the difference is taken. Cups are traded under oz names in Europe as well as the US, and the US ounce is the normal basis for these labels.
Millilitres to ounces
To convert millilitres to ounces, divide by 29.5735 (US) or 28.4131 (UK).
| Volume (ml) | US fl oz | UK fl oz |
|---|---|---|
| 60 | 2.03 | 2.11 |
| 90 | 3.04 | 3.17 |
| 120 | 4.06 | 4.22 |
| 150 | 5.07 | 5.28 |
| 180 | 6.09 | 6.34 |
| 200 | 6.76 | 7.04 |
| 250 | 8.45 | 8.80 |
| 300 | 10.14 | 10.56 |
| 330 | 11.16 | 11.61 |
| 350 | 11.83 | 12.32 |
| 400 | 13.53 | 14.08 |
| 450 | 15.22 | 15.84 |
| 500 | 16.91 | 17.60 |
| 600 | 20.29 | 21.12 |
US and UK fluid ounces: what is the difference?
A US fluid ounce is 29.5735 ml and a UK imperial fluid ounce is 28.4131 ml. The UK ounce is about 3.9 % smaller, so a "12 oz" cup converts to 355 ml on US ounces and 341 ml on UK ounces, a gap of 14 ml. This rarely matters at the counter. It matters when you print a drink volume on a menu or match a supplier's ml figure to your recipe card. Fluid ounces measure volume, so they are not the same as ounces of weight.
Why is the cup's actual capacity not the same as its oz name?
The oz label is the trade name of a format, not a promise of volume. Three different volumes describe a cup, and they are rarely the same figure.
| Term | What it means |
|---|---|
| Nominal size | The oz name of the format, such as "8 oz" |
| Brim-full capacity | Volume when filled level with the rim, from the manufacturer's specification or drawing |
| Fill line (working capacity) | The level a drink is actually served at, leaving room for foam, the lid and carrying |
In many ranges the brim-full capacity is larger than the nominal ml figure, which leaves headspace. Other ranges put the nominal volume close to the brim. Two "8 oz" cups from different makers can therefore serve different amounts. Convert the volume you want to serve in ml, then ask each supplier for brim-full capacity, height and diameters in mm. The full reasoning is in paper cup sizes.
Worked examples
A 355 ml serve. 355 ÷ 29.5735 = 12.00 US oz, which equals the nominal volume of a 12 oz cup. Whether 355 ml fits with room for foam and the lid depends on the cup's brim-full capacity and fill line, which differ by maker, so check the specification.
A UK recipe card. A drink listed at 12 imperial fl oz is 12 × 28.4131 = 341.0 ml, which is 11.53 US fl oz.
What to send when you ask for cup sizes
- Serving volume in ml for each drink.
- Hot, cold or both.
- Preferred nominal sizes, or "supplier to propose" from the fill volume.
- Current lid model if you are keeping your lids.
The packaging RFQ guide lists the other fields a quotation needs.