How Many Milliliters In An Ounce? (+ Conversion Guide!)

Everything you need to know about measuring and converting metric milliliters to fluid ounces, from terms and origin to how many milliliters are in an ounce, and other helpful measurements.

How Many ml In An Oz

There are 29.573 milliliters in a fluid ounce.

Milliliters are a metric unit of measurement, while ounces are an Imperial measurement. The United States is only one of three nations still using the Imperial Measurement system and ounces, the other two are Liberia and Myanmar. With this in mind, the conversion of ounces into the metric volume measurement of milliliters is becoming increasingly important, with so many recipes now using metric measurements.

Not so long ago, when we wanted to cook a recipe, we opened up a cookbook almost certainly written in the USA. Today our first stop is Pinterest, Facebook, Instagram, or Google, and many of the recipes we find there are from beyond our shores and use metric measurements.

What Is an Ounce?

A fluid ounce is the amount of water that weighs one ounce. It is also 1/16th of a pint.

Ounces comes from the Roman term “uncia.” The uncia was 1/12 of a Roman copper bar used as a tool to measure the length of an inch and the weight of an ounce. The Romans had no fluid ounce volume measurement. For that we had to wait on England. Modern ounce weight and volume measurements both come from Britain.

What Is a Milliliter?

A milliliter is the volume of water that weighs one gram.

The liter was introduced in France in 1795 by the revolutionary government after overthrowing the monarchy and everything associated with it, and so the world in time got the metric system. In 1901 an international agreement defined the liter as the space occupied by 1 kg of pure water. A milliliter was then defined as 1/1,000th of a liter or the volume of one gram of pure water.

So there are:

• 1,000 ml in a liter
• 29.57 ml in a fluid ounce
• 237 ml in a fluid cup
• 473 ml in a liquid pint
• 947 ml in a liquid quart
• 3785 ml in a liquid gallon

Quick Conversions

Converting between measurements? These charts will help you out!

Milliliters to Fluid Ounces

Use this chart If you need to convert from metric liters or milliliters to fluid ounces.

Liters	Milliliters	Fluid Ounces
0.03	30	1.0
0.05	50	1.7
0.1	100	3.4
0.2	200	6.8
0.4	400	13.5
0.5	500	16.9
0.75	750	25.4
1	1000	33.8
2	2000	67.6
4	4000	135.3
5	5000	169.1
10	10000	338.2

Fluid Ounces to Milliliters

Use this chart If you need to convert from fluid ounces to metric liters or milliliters.

Fluid Ounces	Milliliters	Liters
1	29.57	0.03
2	59	0.06
3	89	0.09
4	118	0.12
5	148	0.15
6	177	0.18
8	237	0.24
12	355	0.35
16	473	0.47
24	710	0.71
32	946	0.95
64	1892	1.89
128	3785	3.78

Imperial Ounces

A word of caution. The British had to make all of this hard! You see, the UK has been on the metric system for 60 years, but they still like to use ounces, pints, and gallons. The thing is, theirs aren’t the same as ours. A British ounce is only 28.41 milliliters compared to a US fl oz at 29.57. A pint in the UK, however, is 20 ounces. Why? Probably because the Brits like their beers big!

We really just point this out as a matter of interest, and because if you happen to see imperial British ounces, pints, or gallons remember they aren’t the same as in the USA. The chances of seeing these units in a recipe are really slim.