The Difference Between A4 and Letter

Key Takeaways:

  • The world has two predominant paper size systems: international and North American. The international system, represented by the A4 size, is widely used outside of North America and offers a more standardized approach to paper sizes.
  • The standard paper sizes in the US and the rest of the world are determined by different organizations. ANSI (American National Standards Institute) sets the standards for paper sizes in the US, while ISO (International Organization for Standardization) sets the standards for the international system.
  • The beauty of the international system lies in its aspect ratio format. The A series paper sizes, including A4, have a consistent aspect ratio of 1:√2. This means that each size can be easily scaled or reduced without changing its proportions.
  • Standard US sizes, such as Letter size, differ from the A4 size. Letter size is slightly shorter and wider than A4, measuring 8.5 inches by 11 inches. This difference can cause compatibility issues when printing or using documents across different regions.
  • Different US paper sizes have their own common uses. Letter size is the most commonly used size for general business documents, while Ledger/Tabloid size is often used for publications like newspapers and magazines. Legal size, slightly longer than Letter size, is commonly used for legal documents.
  • When comparing ANSI and ISO paper sizes, there are variations in dimensions. For example, ANSI has a slightly different aspect ratio, resulting in a size like ANSI A being wider than A4. Understanding these differences is important for international communication and document sharing.
  • In addition to A4 and Letter sizes, there are other paper sizes used in specific contexts. SRA sizes are commonly used in printing design, while ISO ‘B’ series paper sizes are often used for posters and artwork. ISO ‘C’ sizes are specifically designed for envelopes.

The two predominant paper size systems in the world: International and North American

The two prominent paper size systems worldwide are the international and North American standards. The former is widely used around the world, while the latter is primarily used in North America. These paper size systems have distinct differences in their dimensions and are often suited for different purposes.

Why is A4 and Letter the most popular paper sizes? They differ in size. A4 is known world-wide, measuring 210mm × 297mm. In North America, Letter is the standard: 8.5 inches × 11 inches. Both are important, but the differences can cause issues with compatibility.

Brief overview of A4 and Letter paper sizes

A4 and Letter paper sizes are two well-known formats used for printing and documents. They have different dimensions; A4 being narrower and longer than Letter size. To make this clear, check out the table below:

Paper SizeDimensions (inches)Dimensions (millimeters)
A48.27 x 11.69210 x 297
Letter8.5 x 11216 x 279

A4 measures 8.27 by 11.69 inches or 210 by 297 millimeters. Whereas, Letter size is 8.5 by 11 inches or 216 by 279 millimeters.

Moreover, A4 is the standard paper size used across the world, apart from North America. In the USA and Canada, Letter size is mostly used.

These facts about A4 and Letter paper sizes show how they differ in size and region of usage.

Similarities between A4 and Letter

A4 and Letter paper sizes are widely used and share many similarities. Let’s explore these in more detail.

Their width-to-height ratio is 1:1.41, making them interchangeable. Furthermore, dimensions are standard, accepted globally.

These two sizes are perfect for formal documents, like business letters, reports, and academic papers. The format is professional, yet easily readable.

Both A4 and Letter have the same purpose – conveying information clearly. This is especially important in official communication.

Printers and copiers available today usually handle these sizes. This contributes to their popularity.

The standardized dimensions also make them ideal for storage or filing. No adjustments or modifications are needed.

To summarize, A4 and Letter are similar in size, usage, printing device compatibility, organizational potential, and communication effectiveness. This makes them a top choice for professionals worldwide.

Differences between A4 and Letter

A4 and Letter are two paper sizes used around the world. They vary in size. A4 is a bit taller and narrower compared to Letter. Here’s a table of the main differences between A4 and Letter:

Dimensions (mm)A4Letter

Furthermore, A4 is the standard size used most places, while Letter is mainly used in the U.S. For popularity and use, A4 has a broader global acceptance as it is favored for official documents and publications.

These facts show the big differences between A4 and Letter paper sizes. It’s important to keep these differences in mind when dealing with international partners or making stuff with certain size needs.

Pros and cons of choosing A4

A4 paper has pros and cons. Let’s have a look! The table below features its advantages and disadvantages, along with descriptions.

SizeAllows more content per page
AvailabilityWidely available
CompatibilityCompatible with most printers
OrganizationProvides more space for organizing information

It’s clear that A4 gives users ample space to fit more info per page. Efficiency increases! But, acceptance and availability vary across regions. In Europe, it’s widely used, whereas North America might not have it.

Moreover, A4 is compatible with most printers. However, check if it’s compatible with your printer model before use.

To wrap up, the pros of A4 include its capacity for content and wide availability. The cons are limited acceptance outside Europe and potential compatibility issues with certain printers. Consider these factors before deciding on A4.

Pros and cons of choosing Letter

Letter paper size has its own pros and cons. Let’s look at them!

Portability is great with Letter-sized docs. They fit perfectly in folders and briefcases, so they’re great for busy professionals. But they don’t have much space for content.

Letter is the standard in North America, so it’s accepted and used by many businesses. This makes communication easy. But it could need some changes when used elsewhere or with A4 users.

Letter gives a nice look as it’s wider than A4. The size difference is small, but it can really help with resumes and brochures.

The downside of Letter is printing costs. It’s less common outside of North America, so it can be hard to find compatible printers or photocopiers in certain regions.


A4 and Letter paper sizes have been talked about a lot. A4 is the international standard and is used outside North America, while Letter size is mainly used in the US. Although their dimensions are similar, they can cause compatibility issues when printing documents or fitting them into binders. A4 also offers more space for content since it is bigger. It is important to know these differences when working with international clients or sharing documents around the world. Understanding these paper size discrepancies is essential for smooth communication and collaboration across different parts of the world.

Frequently Asked Questions

1. What is the difference between A4 and Letter?

A4 and Letter are two different paper sizes used in different parts of the world. A4 is the standard paper size in most countries, while Letter is the standard size in the United States.

2. How do the dimensions of A4 and Letter differ?

The dimensions of A4 paper are 210mm x 297mm (8.27in x 11.69in), while the dimensions of Letter paper are 216mm x 279mm (8.5in x 11in). So, A4 paper is slightly narrower and longer compared to Letter paper.

3. Can I use A4 paper instead of Letter?

Yes, you can use A4 paper instead of Letter paper, but you may need to adjust the print settings as the dimensions differ slightly.

4. Is it possible to resize documents from A4 to Letter?

Yes, it is possible to resize documents from A4 to Letter and vice versa. Most word processing software and printers have the option to change the paper size and adjust formatting automatically.

5. Which countries use A4 paper?

A4 paper is used in most countries around the world, including European and Asian countries. It is the standard size for printing documents, letters, and other paper-based materials.

6. Why does the United States use Letter paper instead of A4?

The United States continued to use the older Letter paper size (8.5in x 11in) even after the adoption of the metric system by most other countries. The reasons for this are historical and date back to the colonial era when British papermakers established the standard size for business correspondence.

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Carlos Alonso - I love everything print!

Contrary to popular belief i wasn't born in a vat of magenta ink. Hope you enjoy the content on Catdi Printing. Not all articles are created equal. The quality of writing being dependent on the level of caffeine i had that day. Look forward to working with you and helping you grow your marketing skills/knowledge.Lets chat!Carlos