Quick Answer: Ounces to Milliliters

👉 1 US fluid ounce = 29.5735 milliliters (ml)

To convert oz to ml, multiply your ounce value by 29.5735.

Example: 8 oz × 29.5735 = 236.588 ml

That's it. One number, one multiplication, instant result. Everything else on this page helps you apply that correctly across every real-world context.

The Formula: How to Convert Ounces to Milliliters

ml = oz × 29.5735

This applies to US fluid ounces, which is the standard used across the United States, Canada, and most international recipes published in American English.

The reverse formula (ml to oz):

oz = ml ÷ 29.5735

Critical: US Fluid Ounce vs UK Fluid Ounce

This is where most converters fail their users — and where this page gives you a genuine edge.

There are two different fluid ounce standards in use across English-speaking countries:

Type	Country	1 fl oz in ml
US fluid ounce	USA, Canada	29.5735 ml
UK (Imperial) fluid ounce	United Kingdom, Australia	28.4131 ml

The difference is 1.1604 ml per ounce. At small quantities, this is negligible. But at 32 oz, the difference is 37 ml — enough to affect a recipe, a medication dose, or a manufacturing specification.

Rule of thumb:

• Following an American recipe or using a US-market product label → use 29.5735 ml
• Following a British recipe or UK pharmacopoeia dosing guide → use 28.4131 ml
• For scientific and international work → always specify which standard you are using

All tables and examples in this page use the US fluid ounce (29.5735 ml) unless specifically stated otherwise.

Common Ounce to Milliliter Conversions: The Exact Answers

1 Ounce to ml

1 oz = 29.5735 ml

One fluid ounce is just under 30 ml. The "approximately 30 ml" shortcut is widely used in cooking and everyday contexts, but for medicine, laboratory work, and precise baking, always use 29.5735.

1 oz of water weighs approximately 29.57 grams (since water has a density of ~1 g/ml at room temperature). This is why "fluid ounce of water" and "weight ounce of water" are nearly interchangeable — but only for water.

8 oz to ml

8 oz = 236.588 ml

Eight fluid ounces is one US cup — the most referenced volume measurement in American cooking. A standard glass of water in the US is 8 oz (236.6 ml). A single-serve coffee in most US coffee chains is 8 oz. A standard yogurt container is often 8 oz.

Calculation: 8 × 29.5735 = 236.588 ml

In UK terms: 8 UK fl oz = 8 × 28.4131 = 227.305 ml — note the 9 ml difference, which matters in baking.

12 oz to ml

12 oz = 355.041 ml

Twelve fluid ounces is the standard US soda can volume. It is also the standard volume for a bottle of regular beer in the United States. A 12 oz serving represents 1.5 US cups.

Calculation: 12 × 29.5735 = 355.041 ml

32 oz to ml

32 oz = 946.352 ml

Thirty-two fluid ounces equals one US quart, or approximately 0.946 liters. A standard large water bottle at gyms and sports events is 32 oz. Many hydration goals ("drink a quart of water per day") reference this value.

Calculation: 32 × 29.5735 = 946.352 ml

40 oz to ml

40 oz = 1,182.94 ml

Forty ounces is 1.25 US quarts, or approximately 1.183 liters. Large beverage containers, protein shake bottles, and sports drink jugs frequently come in 40 oz sizes.

Calculation: 40 × 29.5735 = 1,182.940 ml

4 oz to ml

4 oz = 118.294 ml

Four fluid ounces equals half a US cup. Common in baby formula measurements, shot glasses (though a standard US shot is 1.5 oz), and single-serve juice cartons.

Calculation: 4 × 29.5735 = 118.294 ml

3 oz to ml

3 oz = 88.7205 ml

Three fluid ounces appears in cocktail recipes, the TSA's 3-1-1 carry-on liquid rule (travel containers must be 3.4 oz / 100 ml or less), and small medicinal bottle sizes.

Calculation: 3 × 29.5735 = 88.7205 ml

6 oz to ml

6 oz = 177.441 ml

Six fluid ounces equals 3/4 of a US cup. Standard tomato paste cans in the US are 6 oz. Many single-serve yogurt cups are 6 oz. Wine pours at restaurants are typically 5–6 oz (148–177 ml).

Calculation: 6 × 29.5735 = 177.441 ml

20 oz to ml

20 oz = 591.470 ml

Twenty fluid ounces is 1.25 US pints or 2.5 cups. The large size Starbucks cup (Venti hot drinks) is 20 oz. Many medium-to-large sports drinks are sold in 20 oz bottles.

Calculation: 20 × 29.5735 = 591.470 ml

1/2 oz to ml

0.5 oz = 14.7868 ml

Half an ounce is approximately 15 ml — a standard tablespoon measurement in cooking (1 tablespoon = 14.787 ml ≈ 0.5 oz). This conversion is critical in cocktail mixing, where many recipes call for half-ounce measures of liqueurs and bitters.

Calculation: 0.5 × 29.5735 = 14.7868 ml

Complete Oz to ml Conversion Tables

Table 1: Whole Ounce Conversions (US fl oz to ml)

Ounces (oz)	Milliliters (ml)	Rounded
1 oz	29.5735 ml	29.57 ml
2 oz	59.1471 ml	59.15 ml
3 oz	88.7206 ml	88.72 ml
4 oz	118.294 ml	118.29 ml
5 oz	147.868 ml	147.87 ml
6 oz	177.441 ml	177.44 ml
7 oz	207.015 ml	207.01 ml
8 oz	236.588 ml	236.59 ml
9 oz	266.162 ml	266.16 ml
10 oz	295.735 ml	295.74 ml
11 oz	325.309 ml	325.31 ml
12 oz	354.882 ml	354.88 ml
14 oz	414.029 ml	414.03 ml
16 oz (1 pint)	473.176 ml	473.18 ml
20 oz	591.470 ml	591.47 ml
24 oz	709.764 ml	709.76 ml
32 oz (1 quart)	946.353 ml	946.35 ml
40 oz	1,182.94 ml	1,182.94 ml
64 oz (1/2 gallon)	1,892.71 ml	1,892.71 ml
128 oz (1 gallon)	3,785.41 ml	3,785.41 ml

Table 2: Fractional Ounce Conversions

Ounces (oz)	Milliliters (ml)
1/8 oz (0.125)	3.697 ml
1/4 oz (0.25)	7.393 ml
1/3 oz (0.333)	9.858 ml
1/2 oz (0.5)	14.787 ml
2/3 oz (0.667)	19.716 ml
3/4 oz (0.75)	22.180 ml
1 1/4 oz	36.967 ml
1 1/2 oz	44.360 ml
1 3/4 oz	51.754 ml
2 1/2 oz	73.934 ml

Table 3: US vs UK Fluid Ounce Comparison

Volume	US fl oz → ml	UK fl oz → ml	Difference
1 oz	29.5735 ml	28.4131 ml	1.160 ml
4 oz	118.294 ml	113.652 ml	4.642 ml
8 oz	236.588 ml	227.305 ml	9.283 ml
16 oz	473.176 ml	454.609 ml	18.567 ml
32 oz	946.353 ml	909.218 ml	37.135 ml

Table 4: Common Household Reference Points

Item	Volume (oz)	Volume (ml)
1 teaspoon	0.167 oz	4.929 ml
1 tablespoon	0.5 oz	14.787 ml
1 US cup	8 oz	236.588 ml
1 US pint	16 oz	473.176 ml
1 US quart	32 oz	946.353 ml
1 US gallon	128 oz	3,785.41 ml
Standard shot glass (US)	1.5 oz	44.360 ml
Standard wine pour	5 oz	147.868 ml
Standard beer can	12 oz	354.882 ml
Large water bottle	32 oz	946.353 ml

Step-by-Step Guide: How to Convert Ounces to Milliliters

Step 1: Identify your ounce value (e.g., 6 oz)

Step 2: Confirm whether you need US or UK fluid ounces (US = 29.5735, UK = 28.4131)

Step 3: Multiply: oz × 29.5735 (for US)

Step 4: Round to the precision you need

Example: Convert 6 oz to ml

• 6 × 29.5735 = 177.441 ml
• Rounded to nearest ml: 177 ml
• For cooking: approximately 177 ml or ¾ cup

Example: Convert 1.5 oz to ml (cocktail measure)

• 1.5 × 29.5735 = 44.360 ml
• Result: 44.36 ml

Example: Convert 0.25 oz to ml (medication quarter-ounce dose)

• 0.25 × 29.5735 = 7.393 ml
• Result: 7.39 ml (always use full precision for medicine)

Real-World Applications: Where Oz to ml Conversion Matters

Cooking and Baking (USA & UK)

American recipes are written almost exclusively in US customary units — cups, tablespoons, fluid ounces. European, Australian, and British recipes use metric — milliliters and grams. When an American cook follows a British recipe or vice versa, oz-to-ml conversion is unavoidable.

Common kitchen conversions:

• A recipe calling for 8 oz of milk needs 236.59 ml
• 4 oz of olive oil = 118.29 ml (roughly half a cup)
• 12 oz of broth = 354.88 ml (1.5 cups)
• 2 oz of cream = 59.15 ml (about 4 tablespoons)

Baking is particularly unforgiving. The difference between 8 US fl oz (236.6 ml) and 8 UK fl oz (227.3 ml) of milk in a bread recipe is 9.3 ml — enough to affect dough hydration and final texture.

For kitchen conversions beyond liquid volume, our Grams to Ounces Calculator handles dry ingredient weight conversions, and the Oz to Cups Calculator converts fluid ounces directly to cup measurements.

Medicine and Nursing

This is the most precision-critical application of oz-to-ml conversion. In healthcare settings across the USA, the UK, Canada, and Australia, medication dosing is conducted in milliliters — not ounces. However, patients frequently report fluid intake, medication quantities, and supplement doses in ounces from habit.

Why ml is used instead of oz in medicine:

• Milliliters are a metric unit with no regional variation (unlike oz, which differs between US and UK)
• Medication syringes, IV drip equipment, and dosing cups are all calibrated in ml
• Pharmaceutical standards worldwide (USP, BP, European Pharmacopoeia) prescribe doses in mg, mcg, and ml
• Rounding errors in medication dosing can be clinically significant

Key nursing conversions:

• Patient reports drinking 8 oz of water → document as 236.59 ml fluid intake
• Liquid ibuprofen children's dose: 0.5 oz = 14.79 ml (always verify against weight-based dosing chart)
• Oral liquid antibiotics: 1 oz = 29.57 ml — never round to 30 ml without clinical authorization
• IV flush volumes: common 10 ml, 20 ml, 30 ml volumes = 0.34 oz, 0.68 oz, 1.01 oz respectively

Important: For all medical and pharmaceutical conversions, use the full-precision value of 29.5735 ml per US fl oz. Never use the rounded 30 ml approximation for medication dosing without clinical guidance. This page provides educational reference only — always verify medication volumes with a licensed healthcare professional or pharmacist.

Beverages and Coffee Industry

The beverage industry in the US operates almost entirely in fluid ounces for consumer-facing labeling, while production, quality control, and international export documentation use milliliters and liters.

Standard beverage volumes in oz and ml:

Drink	Size (oz)	Size (ml)
Espresso shot	1 oz	29.57 ml
Double espresso	2 oz	59.15 ml
Starbucks Tall	12 oz	354.88 ml
Starbucks Grande	16 oz	473.18 ml
Starbucks Venti (hot)	20 oz	591.47 ml
Standard beer can	12 oz	354.88 ml
Wine pour (restaurant)	5 oz	147.87 ml
Standard shot (US)	1.5 oz	44.36 ml
Small juice carton	6 oz	177.44 ml
Large soda bottle	67.6 oz	2,000 ml (2L)

Fitness and Hydration

Hydration goals in the US are almost always stated in ounces — "drink 64 oz of water per day" or "eight 8-oz glasses." Fitness tracker apps, water bottles, and supplement labels all use ounces. But nutritional databases, international fitness programs, and sports science research use milliliters.

Common fitness conversions:

• Daily water goal: 64 oz = 1,892.71 ml (1.89 liters)
• Pre-workout supplement: 8 oz water = 236.59 ml
• Protein shake: 12 oz milk = 354.88 ml
• Intra-workout: 20 oz sports drink = 591.47 ml
• Post-workout: 16 oz water = 473.18 ml

Our Daily Water Intake Calculator calculates your personalized hydration goal based on body weight and activity level, and our Calorie Calculator pairs with it to manage your complete nutritional intake.

Travel and TSA Liquid Rules

The US Transportation Security Administration (TSA) 3-1-1 rule states that carry-on liquids must be in containers of 3.4 oz (100 ml) or less. This is why 100 ml toiletry bottles are ubiquitous — 100 ml = 3.38 oz, fitting just under the 3.4 oz limit.

Travel liquid conversions:

• TSA limit: 3.4 oz = 100.45 ml (the standard 100 ml bottle is safe)
• Travel shampoo: 2 oz = 59.15 ml
• Travel perfume: 1 oz = 29.57 ml
• Contact lens solution travel size: 4 oz = 118.29 ml (requires doctor's note over TSA limit)

Reverse Conversion: Milliliters to Ounces

To convert ml back to oz, divide by 29.5735:

oz = ml ÷ 29.5735

Milliliters (ml)	US fl oz
30 ml	1.014 oz
50 ml	1.690 oz
100 ml	3.381 oz
150 ml	5.072 oz
200 ml	6.763 oz
250 ml	8.454 oz
330 ml	11.153 oz
355 ml	12.003 oz
500 ml	16.907 oz
750 ml	25.361 oz
1000 ml (1 L)	33.814 oz
1500 ml	50.721 oz
2000 ml (2 L)	67.628 oz

For the reverse direction, use our Milliliter to Ounce Converter for instant results.

Common Mistakes When Converting Ounces to Milliliters

Mistake 1: Confusing fluid ounces (volume) with weight ounces (mass)

This is the most important distinction in measurement. A fluid ounce (fl oz) measures volume — how much space a liquid takes up. A weight ounce (oz) measures mass — how heavy something is. They are completely different units that happen to share the same name.

• 1 fl oz of water ≈ 29.57 ml and weighs approximately 29.57 grams (because water ≈ 1 g/ml)
• 1 fl oz of honey ≈ 29.57 ml but weighs approximately 42 grams (because honey is denser than water)
• 1 fl oz of olive oil ≈ 29.57 ml but weighs approximately 27 grams (because oil is less dense than water)

The formula ml = oz × 29.5735 applies only to fluid ounces. If you are converting weight ounces of a substance to ml, you need to know that substance's density. For dry ingredient weight conversions, use our Grams to Ounces Calculator.

Mistake 2: Using UK values for US recipes (or vice versa)

The 1.16 ml difference per ounce seems minor but compounds significantly. In a recipe using 16 oz of liquid, using the UK factor instead of the US factor produces a 18.6 ml error — nearly 4 teaspoons. Always confirm which fluid ounce standard your recipe or product label uses.

Mistake 3: Rounding 1 oz to 30 ml in medicine

The correct value is 29.5735 ml. Rounding to 30 ml introduces a 0.4265 ml error per ounce. At typical oral medication doses (0.5 to 2 oz), this error range (0.21 to 0.85 ml) can be clinically significant for medications with narrow therapeutic windows. Always use the precise value in medical contexts.

Mistake 4: Forgetting that US cups and UK cups differ

1 US cup = 8 US fl oz = 236.59 ml. 1 UK/metric cup = 250 ml = 8.45 US fl oz. This affects any conversion that moves through cups as an intermediate step.

Mistake 5: Applying the same factor to dry ingredients

"2 oz of flour" cannot be converted to ml using the 29.5735 factor. Flour's volume-to-weight ratio depends on how it is measured (sifted vs packed) and the specific flour variety. Dry ingredients require density-based conversion or direct weighing.

Advanced: Precision vs Rounded Values

The exact definition: 1 US fluid ounce = 29.5735295625 ml (the full defined value from the US National Institute of Standards and Technology, NIST).

For practical purposes, four levels of precision are used:

Precision Level	Value Used	Best For
Approximation	30 ml	Informal cooking, quick mental math
Standard	29.57 ml	Recipes, food labeling
High precision	29.5735 ml	Scientific, pharmaceutical
Full precision	29.5735295625 ml	Metrological, legal standards

When does precision matter?

At 1 oz: difference between 30 ml and 29.5735 ml = 0.4265 ml — negligible for cooking, relevant for medicine.

At 100 oz: difference = 42.65 ml — significant for any application.

At 1,000 oz: difference = 426.5 ml — this is nearly 1.5 US cups of error. In industrial or commercial production, this level of rounding error is unacceptable.

For all calculations on WithinSecs, the full-precision value 29.5735295625 ml is used internally, with results displayed to 4 decimal places by default.

People Also Ask: Direct Answers

What is 1 oz in ml? 1 US fluid ounce = 29.5735 milliliters. The quick approximation is 30 ml, which is acceptable for informal use. For medicine, baking, or scientific purposes, always use the precise value of 29.5735 ml.

Is 30 ml equal to 1 oz? Not exactly. 1 US fl oz = 29.5735 ml, not 30 ml. The 30 ml approximation is commonly used in informal cooking and everyday contexts, but it introduces a 0.4265 ml error per ounce. For medication dosing, use 29.5735 ml precisely.

How many ml is 8 oz water? 8 US fluid ounces of water = 236.588 ml. This equals exactly 1 US cup. Since water has a density of approximately 1 g/ml, 8 oz of water also weighs approximately 236.6 grams.

How to convert oz to ml in nursing? In nursing, multiply the fluid ounce value by 29.5735 to get milliliters. Always use the US fluid ounce value (29.5735 ml), use full precision (never round to 30 ml for medications), and document intake in ml per standard clinical practice. Verify all medication doses with prescribing physician or pharmacist.

What is 32 oz in ml? 32 US fluid ounces = 946.352 ml, which equals 1 US liquid quart or approximately 0.946 liters. This is the volume of a standard large water bottle at gyms and sports facilities.

Is US oz the same as UK oz? No. 1 US fluid ounce = 29.5735 ml; 1 UK (Imperial) fluid ounce = 28.4131 ml. The US fluid ounce is larger by 1.1604 ml. At 8 oz, the difference is approximately 9.3 ml — enough to affect recipes and measurements. Always verify which standard applies to your recipe or label.

How many ml is half an ounce? 0.5 US fluid ounces = 14.787 ml, approximately 1 tablespoon. This measurement appears frequently in cocktail recipes, small medication doses, and flavoring additions in baking.

How to convert oz to ml quickly (mental math)? The fastest mental shortcut: multiply oz by 30. This gives you an approximate answer that is within 1.5% of the true value. For 8 oz: 8 × 30 = 240 ml (actual: 236.59 ml). For precise answers, always use the full factor of 29.5735.

What is 4 oz in ml? 4 US fluid ounces = 118.294 ml, equal to half a US cup. This appears in baby formula measurements, single-serve juice portions, and small cocktail measurements.

What is 12 oz in ml? 12 US fluid ounces = 354.882 ml. This is the volume of a standard US soda can and a standard 12 oz beer bottle. In cup measurements, 12 oz = 1.5 US cups.

How many ml in 20 oz? 20 US fluid ounces = 591.470 ml, approximately 591.5 ml or 0.591 liters. This is the Venti hot drink size at Starbucks and the volume of a standard large sports drink bottle.

What is 40 oz in ml? 40 US fluid ounces = 1,182.94 ml, approximately 1.183 liters. This is 2.5 US pints or 1.25 US quarts — common for large water bottles and specialty beverage containers.

Is a fluid ounce the same as a weight ounce? No. A fluid ounce measures volume (how much space); a weight ounce measures mass (how heavy). For water specifically, 1 fl oz ≈ 29.57 ml and weighs approximately 29.57 grams because water is approximately 1 g/ml. For all other substances, the weight per fluid ounce varies with density.

What is 3 oz in ml? 3 US fluid ounces = 88.7205 ml, approximately 88.72 ml. This is the approximate volume of a standard travel-size toiletry container (though the TSA limit is 3.4 oz / 100 ml).

What is 6 oz in ml? 6 US fluid ounces = 177.441 ml, equal to 3/4 of a US cup. A standard restaurant wine pour is typically 5–6 oz (147.87–177.44 ml), and many US tomato paste cans are 6 oz.

Related Converters You'll Need

Oz to ml is rarely the only conversion you need in any real-world scenario. These tools complete your liquid measurement toolkit:

Volume Conversions:

• Milliliter to Ounce Converter — Reverse conversion, ml back to oz
• Oz to Cups Calculator — Convert fluid ounces to US cups
• Full Unit Converter — All volume units including liters, pints, gallons, tablespoons

Weight Conversions (for dry ingredients):

• Grams to Ounces Calculator — For dry ingredient weight conversion
• Mixed Numbers Calculator — For fractional measurements like 2 3/4 oz

For Cooking and Shopping:

• Discount Calculator — Calculate price savings on beverages and food
• Grocery Calculator — Total grocery cost tracking
• Unit Price Calculator — Compare cost per ml between products

For Fitness and Health:

• Daily Water Intake Calculator — Your personalized hydration target
• Calorie Calculator — Calories in liquid foods and beverages
• Macro Calculator — Protein, carbs, and fat targets for fitness

Features of the WithinSecs Oz to ml Converter

Instant Results: Conversion updates as you type — no button to press, no page to reload.

US and UK Modes: Switch between US fluid ounce (29.5735 ml) and UK Imperial fluid ounce (28.4131 ml) with a single tap.

Fractional Input Support: Enter values like 1.5, 0.25, or 0.333 — the converter handles decimals and fractions equally.

High Precision: Results displayed to 4 decimal places. Full 10-decimal precision used internally.

Reverse Mode: Toggle to ml → oz in the same interface without navigating away.

Mobile-Optimized: Full functionality on any smartphone or tablet. Large input fields, readable output, no zooming required.

Completely Free: No account, no subscription, no limit on conversions.

Conclusion: Convert Ounces to Milliliters WithinSecs

The oz-to-ml conversion is one of the most practically important measurements in everyday life — connecting the US customary system used in American kitchens, product labels, and portion sizes with the metric system used in medicine, international recipes, and scientific contexts worldwide.

The formula is straightforward: multiply by 29.5735 for US fluid ounces. The precision matters: use 29.57 for cooking, 29.5735 for nutrition and fitness, and the full value for medical and scientific applications. And the US/UK distinction is real and significant — never assume which standard a recipe uses without checking.

The WithinSecs Ounces to Milliliters Converter handles all of this — US and UK modes, fractional inputs, reverse conversion, and full precision — in an interface that gives you your answer within seconds.

Bookmark this page. Share it with anyone who cooks from international recipes, works in healthcare, tracks fitness hydration, or travels internationally. And explore the complete WithinSecs toolkit — from the Milliliter to Ounce Converter and Grams to Ounces Calculator to the Daily Water Intake Calculator — for every measurement that matters in your day.

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