A pint is a commonly used unit of measurement for volume, especially for liquids like beer or milk. In the United States, a pint is defined as exactly 16 fluid ounces. However, in many other countries, including the United Kingdom, a pint is defined as approximately 568 milliliters. This difference in definitions can cause confusion when converting between pints and milliliters. In this article, we will provide a detailed overview of how much a pint is in milliliters according to both the US and Imperial pint definitions. We will also discuss the history behind the varying pint measurements and provide conversion charts to easily switch between pints and milliliters.
The US Pint Definition
In the United States, a pint is defined as exactly 16 fluid ounces. This definition was established in the 19th century and is also sometimes referred to as the American pint or US customary pint. One fluid ounce is defined as exactly 29.5735 milliliters. Therefore, by the US pint definition:
- 1 US pint = 16 fluid ounces
- 1 US fluid ounce = 29.5735 mL
- 16 x 29.5735 = 473.176 mL
So in the United States, 1 pint equals 473.176 milliliters. This is an exact figure down to the last decimal place. All volume measurements in the US are based on the US gallon, which is defined as exactly 128 fluid ounces or approximately 3.785 liters. The US pint is precisely 1/8th of a US gallon.
The Imperial Pint Definition
In the imperial system used throughout the United Kingdom and parts of the Commonwealth, a pint is defined as approximately 568 mL. However, unlike the US pint, the Imperial pint is not defined as an exact milliliter measurement. This is because the Imperial system was established before the development of the modern metric system.
The Imperial pint traces its origins to a decree by King Henry VII in 1496 which defined a gallon as 8 pounds of wheat flour weighing 7050 grains. Based on the troy pound at the time and an estimate of the density of wheat flour, this equated to a gallon with a volume of approximately 4.546 liters. Since an Imperial pint is 1⁄8 of a gallon, this gave a pint a volume of approximately 568 mL.
Over the centuries since, the exact conversion between Imperial gallons or pints and metric units has varied slightly based on adjustments to the international definition of the pound. Most recently in 1985, the UK Weights and Measures Act officially defined the Imperial pint as 568.26125 mL.
Therefore, while the Imperial pint equals 568 mL to a close approximation, the exact value is 568.26125 mL.
Comparing US and Imperial Pints
The differing definitions of the pint in the US and Imperial systems creates a notable difference between the size of a pint. Here is a summary comparing the two pint definitions:
| Pint Definition | Fluid Ounces | Milliliters |
|---|---|---|
| US Pint | 16 | 473.176 |
| Imperial Pint | Approx. 19.2 | 568.261 |
As you can see, the Imperial pint is nearly 20% larger than the US pint. This difference must be accounted for when converting pint measurements between the two systems.
Some key facts:
- 1 US pint = 473 mL
- 1 Imperial pint = 568 mL
- 1 Imperial pint ≈ 1.2 US pints
So if you have a recipe that calls for 1 Imperial pint and you live in the US, you would need to use about 1.2 US pints or approximately 19 fluid ounces. Conversely, if you have a US pint measurement and want to convert to Imperial units, you would need to multiply by 0.83.
A Brief History of the Pint
The separate definitions of the pint in the US and Imperial systems have their origins in British law centuries ago. Here is a brief overview:
- Prior to 1824, the pint was not a formally defined unit in the British Imperial system.
- In 1824, the British Weights and Measures Act officially defined the Imperial gallon as the volume of 10 pounds of distilled water weighed against standard pounds and ounces.
- This equated to an Imperial gallon of approximately 4.546 liters and an Imperial pint of 568 mL.
- However in the early 1800s, the US customary system had diverged from Imperial standards. The US gallon was defined smaller at 3.785 liters.
- Therefore, the US pint became 16 fluid ounces or 473 mL, differing from the Imperial pint.
The Imperial and US pint definitions have remained distinct since that time, leading to the discrepancies we must deal with today. Attempts to globally standardize volume units like the pint have been unsuccessful.
Converting Between Pints and Milliliters
When converting between pints and milliliters, the first step is always identifying whether you are using US or Imperial pints. Then, you can apply the appropriate conversion factors:
US Pints to Milliliters
- 1 US pint = 473 mL
- 1 US fluid ounce = 29.5735 mL
To convert US pints to milliliters:
- Multiply the number of US pints by 473
For example:
- 2 US pints x 473 mL/pint = 946 mL
To go from US fluid ounces to milliliters:
- Multiply fluid ounces by 29.5735
For example:
- 12 US fluid ounces x 29.5735 mL/fl oz = 354.882 mL
Milliliters to US Pints
To convert milliliters to US pints:
- Divide milliliters by 473
- Or multiply milliliters by 0.00211338
For example:
- 946 mL / 473 mL/pint = 2 pints
- 1500 mL x 0.00211338 pint/mL = 3.17 pints
To go from milliliters to US fluid ounces:
- Divide milliliters by 29.5735
- Or multiply milliliters by 0.033814
For example:
- 354.882 mL / 29.5735 mL/fl oz = 12 fluid ounces
- 1250 mL x 0.033814 fl oz/mL = 42.268 fluid ounces
Imperial Pints to Milliliters
- 1 Imperial pint = 568.26125 mL
To convert Imperial pints to milliliters:
- Multiply Imperial pints by 568.26125
For example:
- 2 Imperial pints x 568.26125 mL/pint = 1136.523 mL
Milliliters to Imperial Pints
To convert milliliters to Imperial pints:
- Divide milliliters by 568.26125
- Or multiply milliliters by 0.00175951
For example:
- 1136.523 mL / 568.26125 mL/pint = 2 pints
- 750 mL x 0.00175951 pint/mL = 1.32 Imperial pints
Pint Conversions in Recipes and Nutrition Facts
One of the most common situations where pint conversions are necessary is when following recipes, especially those involving measurements of liquids like milk or water. For example, if you are in the US cooking a recipe from a UK cookbook, all the pint measurements will need to be converted from Imperial pints to US pints.
Some tips:
- Carefully check recipes to determine if pints are US or Imperial
- If the recipe is from the UK, Australia, or other Commonwealth nations, assume Imperial pints
- Multiply Imperial pints by 1.2 to convert to US pints, or find equivalent milliliter measurements
- If recipe is from US, Canada, or other countries using US customary units, assume US pints
- Multiply US pints by 0.83 to convert to Imperial pints if needed
You also need to pay close attention to pint measurements when looking at nutrition facts, especially on beverages or dairy products. Food labels in the UK will use Imperial pints while US labels use US pints.
For example:
- A label might list 150 calories per 12 fl oz serving
- In the US, 12 fl oz is a US pint so the label means 150 calories per US pint
- But an equivalent UK label would be 150 calories per Imperial pint
- So the calories per US pint would actually be:
- 150 calories x (12/19.2) fl oz in US pint / fl oz in Imperial pint
- = 93.75 calories per US pint
Pint Conversions in Bartending
Pint conversions also frequently arise when bartending or serving beer, soft drinks, or other beverages. In bars and pubs in the UK, pints refer to Imperial pints of approximately 19 fluid ounces. But US bars and restaurants will serve 12 fluid ounce US pints.
This means draft beers and other drinks will have 20% greater volume for a ‘pint’ in the UK compared to the US. Some tips for bartending pint conversions:
- Memorize key pint conversion factors like US pints = 0.83 x Imperial pints
- If serving an Imperial pint, pour approximately 19 fluid ounces
- If serving a US pint, pour 12 fluid ounces
- Educate customers on the differences if serving pints in a country where the opposite is expected
- Ensure pint glass sizes match the pint definition for where you are located
The varying pint definitions is a source of frequent confusion for tourists unfamiliar with the discrepancies between US and Imperial measurements. Being aware of the differences as a bartender or server allows you to serve customers accurately and avoid overpouring drinks.
Advantages of Using Metric Milliliters
While both the US and Imperial pint units will likely continue to persist in everyday usage, for scientific, culinary, and engineering purposes, using metric milliliters has many advantages:
- Milliliters are part of the standardized SI metric system used globally in science, industry, and trade
- Metric units like milliliters can be easily converted to other units like liters by multiplying or dividing by powers of 10
- The milliliter provides precise volume measurements down to the last decimal
- Metric system avoids confusion from differing country definitions of pints, gallons, etc
- Conversion factors in the metric system are simpler and less prone to errors or approximation
For these reasons, many countries like Australia, New Zealand, and Canada have moved towards requiring metric-only labeling on consumer packages. Given globalization, scientific collaboration across borders, and standardization of manufacturing, milliliters are likely to gain wider adoption worldwide even as cultural usage of traditional units like the pint persists.
Key Takeaways
To summarize the answer to how many milliliters are in a pint:
- There are two different pint definitions still in common use – the US pint and the Imperial pint
- 1 US pint = 16 US fluid ounces = 473 mL exactly
- 1 Imperial pint ≈ 19.2 US fluid ounces or 568.26125 mL
- The Imperial pint is approximately 20% larger than the US pint
- When converting between pints and milliliters, you must know which type of pint is being used
- While pints are convenient and culturally traditional units, using milliliters has advantages for science, industry, and reducing confusion
So in summary, a pint is not a universally defined unit of volume. But whether you are using US pints at 473 mL or Imperial pints at 568 mL, understanding the conversion factors is essential for accurate measurements in cooking, bartending, nutrition labeling, and any application involving liquids. Paying attention to the type of pint being referenced helps avoid potential mistakes. For the most precise measurements and conversions between systems, you can always depend on using milliliters.
