Fluid Ounces to mL Converter (fl oz to mL Calculator)

How many mL are in a fluid ounce?

“Oz” on a scale means mass; “fl oz” means volume. This calculator converts volume only. Check the original recipe or container before choosing US or imperial. If the system is unclear, use its printed mL amount rather than guessing.

How to use the calculator

1. Enter the amount and choose the fluid-ounce system used by your source.
2. Choose the displayed decimal places. The full factor is used before rounding.
3. Read the answer and calculation steps. Results update as you type, or press Enter or the convert button.

mL to fl oz reverses the conversion. Recipe scale multiplies an original liquid amount by required servings ÷ original servings. All volume units retains the 14-unit converter for cups, spoons, pints, gallons, liters and cubic inches.

Presets supply common fluid-ounce amounts. Use result transfers the calculated value to the reverse mode without using the rounded display; Copy result copies the answer with its units. Reset restores that mode’s example. With a mode tab focused, use the arrow keys, Home or End to change modes.

Enter a finite number, including a decimal or scientific notation such as 1e-6. Amounts may be zero; serving counts must be positive. Blank, negative, nonnumeric or numerically out-of-range results show an error and clear the previous answer.

Exact conversion factors and formulas

Why these factors are exact

A US liquid gallon is exactly 231 cubic inches and contains 128 US fluid ounces. Since 1 inch = 2.54 cm and 1 cm³ = 1 mL, the factor is:

231 × 2.54³ ÷ 128 = 29.5735295625 mL

The imperial pint is exactly 568.26125 mL and contains 20 imperial fluid ounces:

568.26125 ÷ 20 = 28.4130625 mL

Check the units

For 8 US fl oz, multiply by 29.5735295625 mL per US fl oz. The US fl oz units cancel, leaving 236.5882365 mL. For the reverse question, divide by mL per fl oz so the result is in fluid ounces.

Recipe scaling

Scaled fl oz = original fl oz × (required servings ÷ original servings)

Convert the scaled amount with the same US or imperial factor. Keep the ratio unrounded until the final answer.

US Fluid Ounces vs UK Imperial Fluid Ounces

US and UK fluid ounces use the same abbreviation, fl oz, but they are different units. The US fluid ounce is approximately 4.08% larger than the imperial fluid ounce; the imperial unit is approximately 3.92% smaller than the US unit. The percentages use different starting volumes. That difference may look small at one ounce, yet it becomes more noticeable as the volume increases.

At 1 fl oz, the difference between the two systems is 1.1604670625 mL. At 8 fl oz, the difference is approximately 9.2837365 mL. At 16 fl oz, the difference is approximately 18.567473 mL. At 32 fl oz, the difference is approximately 37.134946 mL. For a casual drink, this may not affect practical use. For a repeated recipe, nutrition calculation, technical process, or calibrated measurement, using the correct system matters.

How to identify the correct system

Look first at the country and context of the source. US package net-volume declarations and American recipes generally use customary US fluid ounces; Nutrition Facts serving sizes use the separate convention explained below. An older British cookbook or a source that explicitly says “imperial” means UK imperial fluid ounces. If a product lists both fl oz and mL, compare the printed pair: 8 US fl oz is usually paired with about 237 mL, while 8 imperial fl oz is about 227 mL.

Do not determine the system from the letters “oz” alone. Packaging may shorten “fluid ounces” to “fl oz,” and casual writing may omit “fl.” When the measurement appears beside a liquid product, the intended meaning is often volume, but the country-specific system still needs confirmation.

Why a US pint and an imperial pint differ

The difference is not limited to the fluid-ounce size. A US liquid pint contains 16 US fluid ounces, while an imperial pint contains 20 imperial fluid ounces. As a result, an imperial pint is about 568.26 mL and a US liquid pint is about 473.18 mL. This is why converting a pint by assuming only the fluid-ounce factor can be misleading unless the pint system is also identified.

Fluid Ounces to mL Conversion Table

The table below converts common fluid-ounce amounts from both US and imperial fluid ounces into milliliters. The US column applies to customary US liquid measurements. Nutrition Facts serving sizes use the separate 30 mL convention explained below. The UK column applies to imperial fluid ounces. Values are rounded to two decimal places for readability, while the calculator can display additional decimal places when needed.

How to read the table

Find the fluid-ounce amount in the first column and then use the column that matches the measurement system. For example, 3.4 US fl oz equals approximately 100.55 mL. This value is frequently encountered on travel-size liquid containers because 3.4 US fl oz is close to 100 mL. By contrast, 3.4 imperial fl oz equals approximately 96.60 mL.

8 US fl oz = 1 US customary cup ≈ 236.59 mL. 16 US fl oz = 1 US liquid pint ≈ 473.18 mL. 32 US fl oz = 1 US liquid quart ≈ 946.35 mL. The customary-unit relationships are exact; the mL values here are rounded. These relationships are useful when a recipe or container switches between fluid ounces and larger US customary units.

The table rounds only the displayed answer. The conversion should be performed with the full factor first and rounded after multiplication. This prevents cumulative error. For example, using 29.57 instead of 29.5735295625 for a 128 fl oz gallon produces a small discrepancy. That may be irrelevant in casual use, but there is no reason to introduce the discrepancy when a calculator can retain the full factor.

Milliliters to Fluid Ounces Conversion Table

Use this reverse table when the original amount is printed in milliliters. The US and UK outputs are rounded to three decimal places so that small differences remain visible. For a practical kitchen measurement, one or two decimal places are usually sufficient.

Several metric package sizes do not correspond to a whole number of fluid ounces. A 250 mL bottle is approximately 8.45 US fl oz. A 330 mL can is approximately 11.16 US fl oz. A 500 mL bottle is approximately 16.91 US fl oz. A 750 mL bottle is approximately 25.36 US fl oz. A 1 liter container is approximately 33.81 US fl oz.

When comparing products, it is often better to retain the printed metric value instead of forcing it into a rounded fluid-ounce amount. Conversion is helpful for understanding scale, but product labels, recipes, and calibrated tools should be followed in the unit they actually specify whenever possible.

Worked examples: conversion, reverse and scaling

1. A small US measurement: 1.5 fl oz

1.5 × 29.5735295625 = 44.36029434375 mL. To two decimal places, the answer is 44.36 mL.

2. The same number in a different system: 8 fl oz

US: 8 × 29.5735295625 = 236.5882365 mL, or 236.59 mL rounded. Imperial: 8 × 28.4130625 = 227.3045 mL, or 227.30 mL rounded. The difference is 9.2837365 mL.

3. Convert 250 mL back to US fluid ounces

250 ÷ 29.5735295625 ≈ 8.453505675 US fl oz. The two-decimal answer is 8.45 US fl oz. Using the imperial divisor gives approximately 8.80 imperial fl oz.

4. Scale 12 US fl oz from 4 servings to 6

The multiplier is 6 ÷ 4 = 1.5. The new amount is 12 × 1.5 = 18 US fl oz. Then 18 × 29.5735295625 = 532.323532125 mL, or 532.32 mL rounded. This scales a liquid ingredient, not a medication dose.

5. Is 3.4 US fl oz exactly 100 mL?

No: 3.4 × 29.5735295625 = 100.5500005125 mL. Conversely, 100 mL ≈ 3.3814 US fl oz. Familiar rounded package labels are not exact mathematical equalities.

Try it yourself

1. Convert 4 US fl oz to mL, to two decimal places.
2. Convert 20 imperial fl oz to mL, to two decimal places.
3. A recipe uses 6 US fl oz for 2 servings. How many mL are needed for 5 servings?

Rounding and numerical precision

Exact units do not make every displayed answer exact. The conversion factors are exact definitions. The interactive calculator uses standard JavaScript floating-point arithmetic, displays a rounded main result, and shows a higher-precision value with up to 14 significant digits. Reverse conversions often have nonterminating decimals.

Decimal places control the displayed rounding, not the precision of the original measurement. Two decimal places are useful for comparing answers; a measuring jug with coarse markings cannot deliver that level of physical accuracy. Keep the full factor during multi-step arithmetic and round at the end.

Very large values and small positive values that would round to zero are displayed in scientific notation. In that format the setting controls digits after the decimal in the coefficient. Calculations beyond the browser’s finite numerical range are rejected rather than showing a misleading answer.

For example, 8 US fl oz is 236.5882365 mL: 237 mL to zero decimals, 236.6 mL to one, and 236.59 mL to two. The US customary approximation of 30 mL per fl oz is about 1.44% high; it is useful for a rough check, not an exact customary conversion.

Cooking: cups, spoons and scaling

Fluid ounces and mL both measure volume, so the conversion is the same for water, milk or oil. Their masses differ; density is needed only when changing between mass and volume.

• 1 US customary cup = 8 US fl oz = 236.5882365 mL.
• 1 US tablespoon = ½ US fl oz = 14.78676478125 mL.
• 1 US teaspoon = ⅙ US fl oz = 4.92892159375 mL.
• The calculator’s metric cup is 250 mL. Do not assume every recipe’s cup or spoon uses the same standard.

For a liquid ingredient, multiply by new servings ÷ original servings. A 5 US fl oz amount scaled from 3 to 8 portions becomes 13⅓ US fl oz, approximately 394.31 mL. Avoid rounding the 8 ÷ 3 ratio before converting.

Use the cooking conversion calculator for other kitchen units. If the recipe gives an ingredient by weight, use a scale, or a grams-to-mL conversion with a suitable density.

Why a label can show a different mL number

A customary 12 US fl oz volume is 354.88235475 mL, which rounds to 355 mL. Similarly, 1.7 US fl oz ≈ 50.28 mL and 3.4 US fl oz ≈ 100.55 mL. Printed pairs may use rounded or nominal amounts; the calculator does not measure a container’s actual fill.

Package size and serving size can differ. Compare nutrients for the same printed serving volume before comparing bottles. For travel, check the current official rules and labeled container capacity; a rounded fl oz conversion is not a guarantee of acceptance.

Fluid ounces vs ounces by weight

Fluid ounce (fl oz): volume. Ounce (oz) on a scale: mass. A kitchen scale cannot supply a fluid-ounce measurement merely by showing “oz.” Even for water, the units are not interchangeable.

One avoirdupois ounce is exactly 28.349523125 grams. To obtain mL from a mass, you also need the substance’s density at the relevant conditions:

Volume (mL) = mass (g) ÷ density (g/mL)

There is no single oz-to-mL factor for flour, honey, oil and other substances. Confirm whether a recipe’s ambiguous “oz” is mass or volume instead of deciding from the ingredient alone.

For mass conversions, use the weight converter or ounces-to-pounds calculator. For a mass–volume relationship, use a density calculator.

Measure the liquid, not just the calculation

• Use a suitable graduated vessel on a level surface and read the liquid at eye level. Follow the vessel’s instructions for reading the meniscus.
• Choose markings fine enough for the amount: a large jug is a poor tool for a tiny volume.
• Foam and liquid left clinging to a vessel can affect the amount transferred.
• Record the system with the number: US fl oz, imperial fl oz or mL.

A quick reasonableness check

For US customary fluid ounces, multiply by about 30: 8 fl oz is roughly 240 mL and 16 fl oz roughly 480 mL. The exact-factor answers, 236.59 mL and 473.18 mL rounded, are slightly lower.

For imperial fluid ounces, use about 28.4: 20 fl oz is roughly 568 mL. For the reverse US estimate, divide mL by 30. An estimate helps catch a misplaced decimal or the wrong unit; use the full factor for the final calculation.

Common conversion mistakes

• Missing “fl”: an ounce from a scale needs density before it can become mL.
• Wrong system: 8 US and 8 imperial fl oz are different volumes.
• Wrong direction: multiply fl oz by mL per fl oz; divide mL by that factor.
• Premature rounding: do not round the factor or serving ratio at each step.
• Wrong cup: US customary, metric and nutrition-label conventions differ.
• False precision: more decimal places cannot improve the original measurement.
• Assuming every 30 mL statement means the same thing: it is an approximation for customary US fl oz but a specified nutrition-label convention.

Choose the Right Tool for the Measurement You Have

This page is intentionally focused on fluid ounces and milliliters. Use a broader or different calculator only when the measurement problem changes. This separation prevents a liquid-volume question from being confused with mass, density, medication concentration, or unrelated unit systems.