Ounces to Milliliters Converter

The oz to mL converter translates fluid ounces into milliliters instantly — the most searched liquid volume conversion in cooking, nutrition, and medicine. One US fluid ounce equals exactly 29.5735 milliliters. Whether you’re scaling a recipe, measuring medication, or reading a nutrition label, this converter gives you precise results. The reverse — mL to oz — works the same way: divide milliliters by 29.5735. Enter any value above and convert ounces to milliliters instantly. No sign-up required.

What Is the Oz to mL Conversion?

Oz to mL Definition

The oz to mL conversion is the process of expressing a volume measured in US fluid ounces as the equivalent volume in milliliters. One US fluid ounce (fl oz) is a unit of volume in the Imperial/US customary system. One milliliter (mL) is a unit of volume in the metric system equal to one-thousandth of a liter.

Oz to mL

1 US fluid ounce equals exactly 29.5735 milliliters. This is the internationally agreed conversion factor defined by the US National Institute of Standards and Technology (NIST). The conversion is exact — not approximate.

The Oz to mL Formula

The standard formula to convert fluid ounces to milliliters:

mL = fl oz × 29.5735

The reverse formula — mL to oz — divides by the same factor:

fl oz = mL ÷ 29.5735

How Many mL in an Oz?

There are exactly 29.5735 milliliters in one US fluid ounce. This value is not an approximation — it is the defined conversion factor established by international measurement standards. For practical purposes, 30 mL is commonly used as a quick estimate, but the precise figure is 29.5735 mL per fluid ounce.

• 1 fl oz = 29.5735 mL (exact)
• 2 fl oz = 59.1471 mL
• 3 fl oz = 88.7206 mL
• 4 fl oz = 118.2941 mL (approximately half a cup)
• 8 fl oz = 236.5882 mL (exactly 1 US cup)

US Fluid Oz vs. UK Imperial Oz

There are two different fluid ounces: the US fluid ounce (29.5735 mL) and the UK/Imperial fluid ounce (28.4131 mL). This 4% difference matters in precise scientific or pharmaceutical conversions. This calculator uses the US fluid ounce as the default — the most commonly used standard internationally and in digital recipes.

Why the Oz to mL Conversion Matters

For Cooking and Baking

US recipes list liquid ingredients in fluid ounces. International recipes use milliliters. Converting between these two units is the most common liquid measurement conversion in home cooking — from measuring vanilla extract (1 fl oz = 29.57 mL) to scaling cocktail recipes, mixing baby formula, or converting energy drink volumes.

• 1 fl oz vanilla = 29.57 mL — standard baking measurement
• 6 fl oz juice = 177.44 mL — nutritional label reference
• 16 fl oz water bottle = 473.18 mL — common hydration tracking

For Medicine and Pharmacy

Liquid medications in the US are measured in both fluid ounces and milliliters. A standard 1 fl oz = 29.57 mL conversion is essential for dosage accuracy. Pediatric medications are particularly sensitive — a 0.5 fl oz dose equals 14.79 mL. Pharmacy labels frequently list both units, but physicians prescribing internationally may use only one.

For Nutrition Labels and Beverages

US food and beverage labels list serving sizes in fluid ounces. Nutritional databases and fitness apps use milliliters. A 12 fl oz can of soda = 354.88 mL. A 20 fl oz bottle = 591.47 mL. Tracking caloric intake accurately requires knowing the mL equivalent for every fluid ounce measurement on the label.

How to Use the Oz to mL Converter (Step-by-Step)

Step 1 — Enter Your Fluid Ounce Value

Enter any fluid ounce value into the input field — decimals and fractions are accepted. Examples: 1, 1.5, 2.5, 6, 12, 16. The field accepts both whole numbers and decimal values.

Step 2 — Select US or UK Fluid Ounces

The default is US fluid ounces (29.5735 mL per oz). If your measurement comes from a UK or Commonwealth recipe, select UK fluid ounces (28.4131 mL per oz) for an accurate result.

Step 3 — Read Your mL Result Instantly

The converter displays your result in milliliters immediately — no Calculate button needed. The result updates in real time as you type.

Step 4 — Use the Conversion Chart for Quick Reference

For the most common conversions (1 oz, 2 oz, 4 oz, 8 oz, 16 oz), use the reference chart below. This eliminates the need to enter individual values for standard measurements.

Step 5 — Convert Back: mL to Oz

To convert milliliters back to fluid ounces, use the reverse conversion toggle — or use our dedicated mL to oz converter. The mL to oz formula: fl oz = mL ÷ 29.5735.

Oz to mL Conversion Chart — Common Values

The most frequently used fluid ounce to milliliter conversions are listed below:

Oz to mL Formula — How to Calculate Manually

The Standard Oz to mL Formula

This formula works for any fluid ounce value. Multiply the number of fluid ounces by 29.5735 to get the exact milliliter equivalent.

Oz to mL Example Calculation

Example: Convert 6 fl oz to mL

Six fluid ounces equals 177.44 mL — a common measurement for juice glasses, wine servings, and facial cleanser bottles.

mL to Oz Reverse Formula

Example: Convert 250 mL to fl oz

For the complete reverse conversion with its own chart and formula, includes a full mL to fl oz reference table from 10 mL to 1,000 mL.

Why 29.5735? — The Origin of the Conversion Factor

The US fluid ounce is defined as exactly 1/128 of a US liquid gallon. One US liquid gallon = 3785.41 mL (by international agreement). Dividing 3785.41 mL by 128 gives 29.5735 mL per fluid ounce. This is the exact, internationally standardized value — not a rounded approximation. The UK fluid ounce uses a different gallon definition (4546.09 mL ÷ 160 = 28.4131 mL).

What Is 1 Oz in mL? 

1 US fluid ounce = 29.5735 mL exactly. This is the single most searched oz to mL conversion. Here are the closest whole-number values:

• If you need a quick estimate: 1 fl oz ≈ 30 mL (rounded up by 0.43 mL)
• For precise cooking: use 29.57 mL (rounded to 2 decimal places)
• For pharmaceutical use: use 29.5735 mL (full 4-decimal precision)
• For nutrition labels: 1 fl oz = 29.57 mL is the FDA-accepted value

For specific single-value conversions, the most frequently asked questions are: 1 oz = 29.57 mL, 2 oz = 59.15 mL, 4 oz = 118.29 mL, 6 oz = 177.44 mL, 8 oz = 236.59 mL, 16 oz = 473.18 mL.

Benefits of Using This Oz to mL Converter

• Instant conversion — result updates as you type, no button needed
• US and UK fluid ounce modes — choose the correct standard for your recipe or region
• Full conversion chart — 20 common values from 0.5 oz to 128 oz in one table
• Reverse conversion included — toggle to mL to oz without leaving the page
• Decimal and fraction support — enter 1.5 oz, 2.25 oz, 0.75 oz and get precise results
• No sign-up required — free, immediate, works on all devices

Common Mistakes When Converting Oz to mL

Mistake 1 — Confusing Weight Ounces and Fluid Ounces

A weight ounce (oz) measures mass. A fluid ounce (fl oz) measures volume. They are not interchangeable unless the substance is water at standard temperature (where 1 fl oz of water weighs approximately 1 oz by weight). For oil, juice, or syrup, the weight differs from the fluid volume. Always confirm which ounce type your recipe or label uses before converting.

Mistake 2 — Using 30 mL as an Exact Value

Many quick-reference charts round 1 fl oz to 30 mL for simplicity. This is acceptable for cooking estimates, but introduces a 1.5% error (0.43 mL per ounce). For 16 fl oz, this rounding creates a 6.9 mL discrepancy — meaningful in pharmacy, laboratory, and precision baking contexts. Use 29.5735 mL for any application requiring accuracy.

Mistake 3 — Using UK Ounce Values for US Recipes

US and UK fluid ounces differ by 4% (1.16 mL per ounce). If a UK cookbook gives a measurement in fluid ounces and you convert using the US factor, your measurement will be slightly off. Always confirm whether your source uses US or UK fluid ounces before converting.

Mistake 4 — Converting Cups Using Oz Instead of Direct mL

A common error is converting cups by converting oz to mL separately when a direct cup-to-mL factor exists. 1 US cup = 236.588 mL exactly (not 8 × 29.57 = 236.56 mL, which introduces rounding error). For cup conversions, use our cups to oz converter.

Real-World Applications

Cooking: Converting Recipe Measurements

International recipes from the UK, Australia, and Europe use milliliters while US recipes use fluid ounces. A recipe calling for ‘2 fl oz of olive oil’ needs 59.15 mL when using metric measuring cups. Cocktail recipes, coffee brewing ratios (e.g., 1.5 fl oz espresso = 44.36 mL), and sauce measurements all require this conversion.

Medicine: Pediatric Dosing Accuracy

Liquid medications use both fl oz and mL on US labels by FDA regulation. A prescribed dose of 0.5 fl oz = 14.79 mL. Measuring with a standard tablespoon (15 mL) introduces a 1.4% error. For pediatric medications, the exact 29.5735 conversion is clinically required, not an approximation.

Fitness: Tracking Hydration in Different Units

Fitness apps and hydration trackers use milliliters. Water bottles are labeled in fluid ounces in the US. A 16.9 fl oz bottle (the standard US size) = 499.8 mL, usually rounded to 500 mL on nutrition labels. Tracking daily water intake of 64 fl oz (8 cups) = 1,892.71 mL ≈ 1.9 liters.

Use our mL to cups converter to easily convert milliliters into cups in seconds. Simply input your value and get precise results, making recipe measurements simple and hassle-free.

Final Thoughts

One US fluid ounce equals exactly 29.5735 milliliters — not approximately 30 mL. This precision matters in cooking, medicine, and nutrition tracking. Use the converter above for instant results, the chart for quick reference, and the formula (mL = fl oz × 29.5735) when calculating manually. 

Frequently Asked Questions

How many mL in an oz?

There are exactly 29.5735 mL in one US fluid ounce. For quick estimates, 30 mL is often used, but the precise value is 29.5735 mL. The UK fluid ounce is slightly smaller at 28.4131 mL.

How many ml is 1 oz?

1 US fluid ounce equals exactly 29.5735 milliliters. This is the NIST-defined conversion factor. In practice, 1 oz is often rounded to 30 mL for cooking, but 29.57 mL is the accurate value for nutritional and pharmaceutical purposes.

How many oz in 100 mL?

100 mL equals 3.3814 US fluid ounces. Formula: fl oz = 100 ÷ 29.5735 = 3.3814 fl oz. This is a common measurement for cosmetic and skincare product bottles.

Is 1 oz the same as 30 mL?

No — 1 US fluid ounce equals 29.5735 mL, not exactly 30 mL. The 30 mL approximation is used for convenience in cooking and is close enough for most recipes. However, for medical, pharmaceutical, or scientific measurements, use the exact value of 29.5735 mL.

What is the difference between US and UK fluid ounces?

The US fluid ounce equals 29.5735 mL. The UK (Imperial) fluid ounce equals 28.4131 mL — approximately 4% smaller. This difference comes from different definitions of the gallon in each system. Always check whether a recipe or label uses US or UK measurements before converting.

How do I convert 2 oz to mL?

2 US fluid ounces equals 59.1471 mL. Formula: mL = 2 × 29.5735 = 59.1471 mL. Rounded to two decimal places: 59.15 mL. This is a common measurement for espresso shots, medicine doses, and small bottle servings.

How many mL is 8 oz of water?

8 US fluid ounces of water equals exactly 236.588 mL — which is also exactly 1 US cup. This is a standard reference point: 1 cup = 8 fl oz = 236.59 mL. Eight ounces of water is one of the most common hydration servings.

What is 16 oz in mL?

16 US fluid ounces equals 473.176 mL — equivalent to 1 US pint. This is the volume of a standard US water bottle (often labeled 473 mL or 16 fl oz) and a common beverage serving size in the US.

About This Converter

This oz to mL converter is part of Intelligent Calculator’s Conversion suite — built on NIST measurement standards, SI unit definitions, and US/UK Imperial unit equivalence tables. Conversion factor: 1 US fl oz = 29.5735 mL (exact). Free. No sign-up.