# How do I convert ml to oz?

Converts milliliters (mL) to fluid ounces (fl oz) and back, with the exact unit definitions.

- Page: https://www.acalculator.org/convert/ml-to-oz
- JSON spec: https://www.acalculator.org/convert/ml-to-oz.json
- Version: 0edb9419f0a3

## Default answer

Example with the default inputs (Milliliters (mL) 1): 1 mL = 0.033814 fl oz.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| value | Milliliters (mL) | The amount in milliliters to convert. |
| result | Fluid ounces (fl oz) | The same amount in fluid ounces. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| value | Milliliters (mL) | The amount in milliliters to convert. |
| result | Fluid ounces (fl oz) | The amount in fluid ounces. |

## Method

fl oz = mL × 0.0338140227018

## Assumptions

- 1 milliliter = 0.0338140227018 fluid ounces, from the exact definitions in NIST SP 811.
- Cups, ounces, tablespoons, pints, quarts, and gallons are US customary units: 1 US cup is 8 US fluid ounces.
- Ounces here are US fluid ounces, a volume. An ounce of weight (1/16 lb) is a different unit.
- The answer shows at most 6 decimal places; the calculation keeps full precision.

## Worked examples

1. value = 1 gives result = 0.033814. Source: exact unit definitions in NIST SP 811 (2008), Appendix B.8.
2. value = 250 gives result = 8.453506. Source: exact unit definitions in NIST SP 811 (2008), Appendix B.8.
3. result = 8.453506 gives value = 250. Source: exact unit definitions in NIST SP 811 (2008), Appendix B.8.

## FAQ

### How many fluid ounces are in a milliliter?

1 milliliter is 0.033814 fluid ounces, from the exact unit definitions (NIST SP 811).

### How do I convert ml to oz?

Multiply by 0.033814: fl oz = mL × 0.0338140227018. For example, 1 mL × 0.033814 = 0.033814 fl oz.

### How do I convert oz back to ml?

Multiply by 29.57353, or type the fluid ounces into the second box and the converter works it out. 1 fluid ounce is 29.57353 milliliters.

### Is an ounce here a weight or a volume?

A volume: the US fluid ounce, 1/8 of a US cup (29.57 mL). An ounce of weight (1/16 lb, 28.35 g) only matches a fluid ounce for water and liquids like it.

## Sources

- NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B.8. https://www.nist.gov/pml/special-publication-811