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US fluid ounces to US cups converter

Convert US fluid ounces to US cups (oz to cups) with the exact factor, a conversion chart and worked steps.

Drafted with AI writing toolsUpdated Checked examples: 3

fl oz
Try
US cups
cup
US cups: 1.5 cup
Significant figures: 12; Nearest, ties away from zero
Conversion
12 fl oz = 1.5 cup
1 cup in US fluid ounces
8fl oz

12 fl oz is about 1.5 cup. In the other direction, 1 cup ≈ 8 fl oz.

US fluid ounces to US cups

02468204060fl ozcup12 → 1.5
Oz to cups chart Rows: 12
US fluid ouncesUS cups
10.125
20.25
40.5
60.75
81
101.25
121.5
162
202.5
243
324
648
How it's calculated S

  1. Conversion factor

    1 fl oz=0.125 cup1\ \text{fl oz} = 0.125\ \text{cup}

    Exact by definition.

  2. Multiply

    12×0.125=1.5 cup12 \times 0.125 = 1.5\ \text{cup}

About the US fluid ounces to US cups converter

To convert US fluid ounces to US cups, multiply by 0.125; to convert back, multiply by 8. For example, 12 fl oz is about 1.5 cup. Displayed factors and results may be rounded.

US fluid ounces are volume measures used on beverage packaging and measuring cups. They are different from ounces of mass and from imperial fluid ounces. Use the labelled US amount as the starting value, and do not infer an ingredient's weight from volume alone.

US fluid ounce: 1 US fl oz = 1/128 US gal = 29.5735295625 mL. These values are exact.

Both units are defined exactly. Calculations use 50 significant digits and round only for display.

How to convert ounces to cups

Divide US fluid ounces by 8: cups = fl oz ÷ 8. So 12 fl oz = 1.5 cups, 16 fl oz = 2 cups and 32 fl oz = 4 cups. That works for fluid ounces, which measure volume. Ounces weighed on a scale need the ingredient's weight per cup instead.

Fluid ounces or ounces of weight?

On US labels, "fl oz" is a volume and a plain "oz" is a weight. Only the volume converts to cups by dividing by 8.

A US cup of water weighs about 8.3 oz, so treating weight ounces as fluid ounces nearly works for water.

Flour is far lighter: at the 120 g per cup King Arthur Baking lists, 8 oz of flour is about 1.9 cups. At 198 g per cup, 8 oz of sugar is about 1.15 cups.

Why a cup is 8 fluid ounces

The US customary cup is defined as 8 US fluid ounces, half a US pint (NIST Handbook 44, Appendix C). In milliliters, a fluid ounce is 29.5735295625 mL and a cup 236.5882365 mL, exactly eight times as much.

Fluid ounces to cups chart

US fluid ouncesUS cups
20.25
40.5
60.75
81
121.5
324

Every 2 fl oz is a quarter cup, so 10 fl oz is 1¼ cups. A 64 fl oz jug, half a US gallon, holds 8 cups, and a 500 mL bottle (16.9 fl oz) holds about 2.1 cups.

UK fluid ounces and metric cups

  • Imperial fluid ounce: 28.4130625 mL, about 3.9% smaller than the US one (official imperial tables). 8 UK fl oz is 0.96 US cup, and the 10 fl oz in half a UK pint is about 1.2 US cups.
  • Metric cup: 250 mL. Twelve US fl oz is 354.88 mL, which is 1.419529419 metric cups, not 1.5.

Common mistakes

  • Dividing a weight by 8. A bag holding 8 oz of flour by weight is nearly 2 cups, not 1. Weigh it, or use the ingredient's grams per cup.
  • Multiplying by 8. 8 fl oz becomes 64 cups. The cup figure is always the smaller number.

The cups to ounces converter goes the other way, and oz to mL gives milliliters. For ounces of weight, use ounces to grams or the cooking converter.

Worked examples

12 fl oz to cup

US fluid ounces (fl oz)
12 fl oz
US cups
1.5 cup

Checked against: Exact-fraction computation from the legal unit definitions

8 fl oz to cup

US fluid ounces (fl oz)
8 fl oz
US cups
1 cup

Checked against: Exact-fraction computation from the legal unit definitions

32 fl oz to cup

US fluid ounces (fl oz)
32 fl oz
US cups
4 cup

Checked against: Exact-fraction computation from the legal unit definitions

Questions

How many US cups are in one US fluid ounce?

1 fl oz is about 0.125 cup. US fluid ounce: 1 US fl oz = 1/128 US gal = 29.5735295625 mL. These values are exact.

How do I convert US fluid ounces to US cups?

Multiply by 0.125: 12 fl oz × 0.125 ≈ 1.5 cup. To convert back, divide by the same factor. The factor shown may be rounded.

Is a cup 240 mL or 236.6 mL?

Both are in use. The US customary cup in recipes is approximately 236.588 mL. US nutrition labels use a rounded "legal cup" of 240 mL (21 CFR 101.9), and the metric cup used in Australia, New Zealand and Canada is 250 mL.

About this calculator

cup=fl oz×0.125\text{cup} = \text{fl oz} \times 0.125

Sources

  1. 21 CFR 101.9(b)(5)(viii), Nutrition labeling of food
  2. Safe Food for Canadians Regulations, section 241
  3. New Zealand Ministry of Education, Cooking: Measuring
  4. NSW Health, Healthy Food for Babies and Toddlers: metric cup and spoon measures
  5. NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B
  6. NIST Handbook 44, Appendix C: General tables of units of measurement
  7. BIPM, The International System of Units (SI Brochure), 9th edition

Checked against references

This calculator includes 3 worked examples with independently sourced answers. They run in the test suite, and you can run them here too.

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