18 US fluid ounces to US cups
2.250 cup
18 fl oz = 2.250 cup.
US cups
2.250cup
18 fl oz = 2.250 cup
In short
How many US cups is 18 US fluid ounces?
18 fl oz = 2.250 cup. 1 US fluid ounce = 0.125000 US cups, so the working is 18 × 0.125000 = 2.250.
The working
The factor below is an exact definition rather than a measurement, so nothing is approximated in the arithmetic. The only rounding on this page happens where a number is displayed.
1 US fluid ounce = 0.125000 US cups 18 × 0.125000 = 2.250
How much precision do you need?
Each row is the same answer cut at a different number of decimals, with what that choice costs you. Pick the shortest row whose error is smaller than whatever you are measuring with.
| Rounded to | Answer (cup) | Off by |
|---|---|---|
| Whole number | 2 | −0.25000 |
| 1 decimal | 2.3 | +0.05000 |
| 2 decimals | 2.25 | exact |
Round trip: take 2.250 cup back the other way and you land on 18.0000 fl oz — a drift of 0.0000 fl oz. That gap is the rounding, not the conversion.
Frequently asked questions
What is 18 US fluid ounces in US cups?
18 US fluid ounces is 2.250 US cups. 1 US fluid ounce = 0.125000 US cups, so the working is 18 × 0.125000 = 2.250.
How accurate is 2.250 cup?
Rounding to 2.250 cup and converting straight back gives 18.0000 fl oz, a drift of 0.0000 fl oz from the 18 you started with. The factor itself is exact; every bit of that difference comes from the rounding, not the conversion.
Nearby values
Any value at all
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