How Much Milk Comes in a Bag of Milk?

December 22, 2025 •

3 min read

In Canada, a standard outer bag of milk typically contains three 1 1/3-litre pouches, totaling 4 litres. However, the exact answer to how much milk comes in a bag of milk varies significantly based on geographic location and the type of product.

Quick Summary

The volume of bagged milk is not uniform globally; retail sizes range from 0.5L in India to 4L total in Canada, while breast milk bags are much smaller.

Key Points

Canadian standard: A Canadian 4-litre bag of milk contains three 1 1/3-litre pouches.
International variations: Bagged milk in other countries like India (0.5L) or Europe (1L) comes in different volumes.
Metric conversion: The Canadian system arose partly from the country's metric system transition in the 1970s.
Breast milk bags: These are distinct products, typically holding 3-6 ounces for expressed breast milk storage.
Pros and cons: Bagged milk offers advantages like less plastic waste and lower cost but requires a separate pitcher and can be messier.
Pitcher required: Retail bagged milk requires a specific pitcher for easy pouring after a corner is snipped.

Canadian Bagged Milk: The 4-Litre Standard

For many living in Canada, the milk bag is a familiar sight in the dairy aisle. Specifically in Ontario, Quebec, and the Maritimes, the standard retail package of milk is a large outer bag containing three smaller pouches. Each of these individual pouches holds 1 1/3 litres (approx. 1.4 US quarts), bringing the total volume to 4 litres, which is roughly equivalent to an imperial gallon or just over a US gallon.

The reason behind this unusual packaging can be traced back to Canada's adoption of the metric system in the 1970s. Rather than retooling machinery to accommodate new bottle sizes, many dairies found it more economical and efficient to simply adjust the plastic bag machines to produce the new 1 1/3-litre volume. This historical shift solidified the use of bagged milk in many parts of the country. These pouches are then placed into a dedicated plastic pitcher for easy pouring.

Global Variations in Bagged Milk Volumes

While the 4-litre system is a Canadian staple, the concept of bagged milk exists elsewhere with different volumes. This regional disparity means the question "how much milk comes in a bag of milk?" has no single answer.

Other International Examples

India: It is common to find milk sold in bags containing 0.5 litres (approx. 0.9 imperial pints).
South America, Iran, Israel, and parts of Europe: A typical milk bag in these regions contains approximately 1 litre.

This variety highlights how local economies, regulatory standards, and consumer preferences dictate packaging formats. From cost-effectiveness to perceived convenience, multiple factors contribute to a region's choice of milk container.

Comparing Bagged Milk with Other Packaging Formats


Feature	Bagged Milk	Plastic Jug	Cardboard Carton
Common Volume (Canada)	4 litres (3 x 1.33L pouches)	4 litres, 2 litres, 1 litre	2 litres, 1 litre, 500ml
Environmental Impact	Uses less plastic overall	Less efficient, requires more material	Often recyclable, but requires complex processing
Cost	Generally more economical	Mid-range	Often slightly higher
Storage	Requires a reusable pitcher	Freestanding	Freestanding
Convenience	Can be messy if not handled correctly	Easy to pour and store	Easy to pour and store

Breast Milk Storage Bags: A Different Standard

When discussing milk in bags, it is crucial to distinguish between retail dairy products and breast milk storage bags. These are designed for a completely different purpose—freezing and storing expressed breast milk—and come in much smaller sizes.

Most breast milk bags are designed to hold 3 to 6 ounces (approx. 90 to 180 ml) per bag.
It is generally recommended to store smaller, single-feeding portions to minimize waste.
Measurements on these bags can sometimes be inaccurate, so it is often advised to measure milk using a bottle before pouring it into the bag.

This differentiation is important for anyone searching for information, ensuring they find the correct details for their needs. While both involve milk in bags, their contexts are worlds apart.

The Pros and Cons of Bagged Milk

Advantages of Bagged Milk

Less Plastic Waste: Bagged milk generally uses less plastic packaging per litre than traditional jugs, making it a more environmentally friendly option.
Lower Cost: The reduced cost of manufacturing and shipping plastic pouches can lead to lower prices for consumers.
Efficiency: The design is highly efficient for transport and storage before being placed in a pitcher.

Disadvantages of Bagged Milk

Spills: Cutting the corner incorrectly or mishandling the bag can lead to spills.
Pitcher Dependency: A dedicated pitcher is required for pouring, which is an additional purchase.
Storage Mess: Accidental leaks or spills within the pitcher can create a mess to clean.

Conclusion

In summary, the amount of milk that comes in a bag depends heavily on location and the specific product. In Canada, retail milk bags contain three 1 1/3-litre pouches, for a total of 4 litres, a practice stemming from the country's metric conversion. In other parts of the world, such as India or Europe, single pouches holding 0.5 or 1 litre are common. For breast milk storage, specialized bags are used for much smaller, single-serving portions. Understanding these regional and product-specific variations is key to knowing what to expect when you encounter milk in a bag. The Canadian Encyclopedia explains the history of bagged milk in Canada.

Frequently Asked Questions

Milk is sold in bags in some countries, like Canada and India, primarily due to cost efficiency and reduced packaging waste. For Canada, the practice was adopted during the metric conversion in the 1970s as a simpler and cheaper alternative to retooling bottling plants.

To pour milk from a bag, you first place the pouch into a reusable plastic pitcher designed for this purpose. Then, a corner of the bag is snipped off with scissors to create a spout for pouring.

Yes, bagged milk is often less expensive than carton or jug milk. The lower cost is typically due to the reduced amount of packaging material and the efficiency of manufacturing the plastic pouches.

No, breast milk storage bags are not designed for regular milk. They are sterilized, much smaller, and intended for freezing and storing expressed human milk in single-feeding portions, not for bulk storage of retail dairy milk.

While the bags themselves are durable, spills can occur if the bag is mishandled or if the corner is not cut correctly when placed in the pitcher. It is generally not more prone to leaking during transport or storage than other milk containers.

The 4-litre bag format in Canada is a result of the country's adoption of the metric system. It was more cost-effective for dairies to adjust their existing bagging machines from imperial quarts to 1 1/3-litre pouches, with three pouches forming the new 4-litre standard.

For retail bagged milk, the volume is reliably measured by the manufacturer. For breast milk storage bags, however, the printed volume markers can be inaccurate due to the bag's flexible nature, so it is best to measure the milk in a bottle first.