A Series Guide | Complete A Paper Sizes Reference

ISO 216

What is the A Series Paper Size?

The A series is the most widely used paper size standard in the world. Defined by ISO 216, it is based on a simple mathematical principle: the aspect ratio of √2:1. This means that each size is exactly half the area of the previous size, making scaling and copying incredibly easy.

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The √2 Aspect Ratio

Every A series paper has an aspect ratio of 1:√2 (approximately 1:1.414). This unique ratio allows each size to be exactly half the area of the previous size when folded in half. This makes the system infinitely scalable and practical.

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Global Standard

The A series is used in almost every country except the United States and Canada. A4 is the most common paper size worldwide, used for office documents, letters, forms, and everyday printing.

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History of the A Series

The A series was first proposed by German scientist Georg Christoph Lichtenberg in 1786. It was later standardized by the German Institute for Standardization (DIN) as DIN 476 in 1922. In 1975, it became the international standard ISO 216. Today, it is the most widely used paper size system globally.

Sizes

📏 A Series Paper Sizes

Complete list of all A series paper sizes with dimensions in mm, inches, and pixels at 300 DPI.

A0841 × 1189 mm

A1594 × 841 mm

A2420 × 594 mm

A3297 × 420 mm

A4210 × 297 mm

A5148 × 210 mm

A6105 × 148 mm

A774 × 105 mm

A852 × 74 mm

A937 × 52 mm

A1026 × 37 mm

Resolution

📱 A Series Pixel Dimensions

Pixel dimensions for each A series size at common resolutions.

Size	72 PPI	96 PPI	150 DPI	300 DPI	600 DPI
A0	2384 × 3370	3179 × 4494	4967 × 7022	9933 × 14043	19866 × 28087
A1	1684 × 2384	2245 × 3179	3508 × 4967	7016 × 9933	14032 × 19866
A2	1191 × 1684	1588 × 2245	2481 × 3508	4961 × 7016	9921 × 14032
A3	842 × 1191	1123 × 1588	1754 × 2481	3508 × 4961	7016 × 9921
A4	595 × 842	794 × 1123	1240 × 1754	2480 × 3508	4961 × 7016
A5	420 × 595	560 × 794	874 × 1240	1748 × 2480	3496 × 4961
A6	298 × 420	397 × 560	620 × 874	1240 × 1748	2480 × 3496

Reference

📊 A Series Comparison Table

Full comparison of all A series sizes in mm, inches, and area.

Size	mm	inches	Area	Common Use
A0	841 × 1189	33.1 × 46.8	1.0 m²	Billboards, banners, world maps
A1	594 × 841	23.4 × 33.1	0.5 m²	Large posters, architectural plans
A2	420 × 594	16.5 × 23.4	0.25 m²	Medium posters, plans
A3	297 × 420	11.7 × 16.5	0.125 m²	Small posters, drawings
A4	210 × 297	8.3 × 11.7	0.0625 m²	Standard office documents
A5	148 × 210	5.8 × 8.3	0.03125 m²	Flyers, brochures, notebooks
A6	105 × 148	4.1 × 5.8	0.01563 m²	Notecards, postcards
A7	74 × 105	2.9 × 4.1	0.00781 m²	Small notepads, tags
A8	52 × 74	2.0 × 2.9	0.00391 m²	Very small notepads
A9	37 × 52	1.5 × 2.0	0.00195 m²	Miniature notes
A10	26 × 37	1.0 × 1.5	0.00098 m²	Extremely small notes

Applications

🖨️ Real-World Uses of A Series Paper

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A4 - The Office Standard

A4 is the most common paper size in the world. It's used for office documents, letters, forms, reports, and everyday printing. Almost every printer supports A4, making it the universal standard for business and personal use.

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A3 - The Creative Size

A3 is the go-to size for posters, presentations, drawings, and spreadsheets. It's also popular for architectural plans, engineering schematics, and small posters. A3 is exactly twice the area of A4.

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A2, A1, A0 - Large Format

These sizes are used for large posters, banners, billboards, and architectural presentations. A0 is the largest standard size, perfect for world maps and high-impact displays.

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A5, A6 - Compact Sizes

A5 is used for flyers, brochures, notebooks, and diaries. A6 is the classic notecard and postcard size, perfect for invitations and personal correspondence.

Tips

💡 Professional Tips for A Series Paper

🎯 Choose the Right Size

Always select the appropriate A size for your project. A4 for office documents, A3 for posters and presentations, A5 for flyers and brochures. The right size saves paper and improves readability.

📐 Scaling Made Easy

The √2 aspect ratio means scaling between A sizes is simple. A3 to A4 reduces by 50% area, A4 to A3 enlarges by 100% area. Use our converters for precise scaling.

🖨️ Print Settings

Always check your printer settings to match the correct A size. Most printers support A4, A3, and A5. For larger sizes, use professional print services.

📄 Document Design

Design your documents with the final paper size in mind. Use margins of at least 10mm, and consider the viewing distance for larger sizes like A0 and A1.

FAQ

❓ Frequently Asked Questions

What is the most common A series size? ▼

A4 (210 × 297 mm) is the most common A series size worldwide. It is the standard for office documents, letters, and everyday printing.

How are A series sizes related? ▼

Each A size is exactly half the area of the previous size. For example, A3 is half the area of A2, and A4 is half the area of A3. The aspect ratio remains √2:1.

What is the largest A series size? ▼

A0 (841 × 1189 mm) is the largest standard A series size. It has an area of exactly 1 m².

What is the smallest A series size? ▼

A10 (26 × 37 mm) is the smallest standard A series size. It is rarely used in everyday applications.

Why is the A series aspect ratio √2:1? ▼

The √2:1 aspect ratio allows each size to be exactly half the area of the previous size when folded in half. This makes the system infinitely scalable and practical.

What is the difference between A4 and Letter? ▼

A4 is 210 × 297 mm, slightly narrower and longer than Letter (216 × 279 mm). A4 is the international standard, while Letter is used in the US and Canada.

How many A4 pages fit on A0? ▼

16 A4 pages fit on one A0 sheet. A0 is 16 times the area of A4.

What is the history of the A series? ▼

The A series was first proposed by Georg Christoph Lichtenberg in 1786. It was standardized as DIN 476 in 1922 and became ISO 216 in 1975.

Tools

🔗 Related A Series Tools

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📄 A Series Paper Sizes Guide