Paper Size Chart: A, B, Letter, Photo and Postcard Sizes, Uses, How to Choose and Scaling

A list of paper sizes is easy to follow when you split it by standard. The paper commonly used in Japan falls into four broad groups.

• A series: a standard used in many countries around the world (ISO 216, JIS P 0138)
• B series: a standard whose dimensions differ between Japan's JIS and ISO
• North American paper: Letter, Legal and Tabloid, defined in inches
• Photo, postcard and business card: sizes fixed for each use

The key point: the same "B5" can have different dimensions depending on which standard's B5 it is.

This article covers the following.

• A paper size chart (mm, cm, inches, uses)
• The rules of the A and B series (area, ratio, folding in half gives the next size)
• How the ISO B series differs from the JIS B series
• North American Letter, Legal and Tabloid
• Sizes of photos, postcards and business cards
• How the sizes match everyday items, and sizes you can print at a convenience store
• How to choose by use, enlargement and reduction ratios, and common mistakes

The dimensions are shown in tables based on the standards (ISO 216, JIS P 0138).

Conclusion: how should you read the paper size list?

The paper sizes are listed in the table below. The "Series" column shows which standard each paper belongs to.

Source (20)

• JIS P 0138, ISO 216, ANSI/ASME Y14.1
• Japan Post domestic postal terms, Art. 21
• Fujifilm, multifunction printer photo prints (L and 2L are customary, not formal standards)
• Customary business card size in Japan (not a formal standard; may differ by a few mm)
• Camera no Kitamura, print size guide (photo shop listing)
• Epson Japan, photo paper sizes (KG)
• Canon Japan, photo glossary: print paper sizes
• Canon Japan, photo glossary (6.5 × 8.5 in converted to mm)
• Epson Japan, photo paper sizes (Rokugiri)
• Epson Japan, photo paper sizes (Yotsugiri)
• Camera no Kitamura, print size guide (Canon software lists "Wide Yotsugiri" as 10 × 15 in, a longer long side)
• Epson Japan, photo paper sizes (Hangiri)
• Ministry of Foreign Affairs of Japan, passport photo standard
• Daio Paper, Fresh Color drawing paper, full sheet (same as JIS P 0202 shiroku-ban)
• Half of the shiroku-ban full sheet (check the pack for the product size)
• Daio Paper, Fresh Color drawing paper, yotsugiri (100-sheet pack)
• Ministry of the Environment, Animal Welfare Week poster contest rules
• Daio Paper, Fresh Color drawing paper, yatsugiri (100-sheet pack)
• Hyogo Prefecture, election awareness poster contest (yotsugiri, yatsugiri or similar)
• Half of the yatsugiri sheet (Daio Paper); check the pack for the product size

The dimensions in the table are the finished size of the paper after trimming (trimmed size). They are given as "width × height", in portrait orientation.

The cm column is the mm value divided by 10. The inch column is the mm value divided by 25.4, rounded to two decimal places.

When in doubt, read the table like this.

• Documents and copies: look at A4 and A3 in the A series
• Notebooks, books and school handouts: look at the B series (JIS)
• Dealing with the US or Canada: look at the North American rows
• Photos, postcards and business cards: look at the last four rows

If in doubt, take A4 as the base and think in halves or doubles. Half of A4 is A5, and two A4 sheets side by side make A3.

How can you convert the values in the paper size list with a calculator?

Conversions that are not in the list can be worked out with the tool above. Choose a paper size to see it in mm, inches and pixels, along with the enlargement ratio.

The tool runs entirely in your browser. The values you enter are not sent anywhere.

The same paper has a different pixel count depending on the dpi (dots per inch). How pixel counts work is explained in detail in A4 size in pixels.

How is the A series of paper sizes defined?

The A series sets the area of A0 to 1m² and the ratio of the short side to the long side to 1 : √2. Folding a sheet in half gives the next size.

As the figure shows, half of A0 is A1, and half of A1 is A2. Each step up in number halves the area.

Checking with the dimensions of A0 gives the following.

• Area: 841 × 1189 = 999,949mm² → almost 1m²
• Ratio: 1189 ÷ 841 = 1.4138 → almost √2 (1.4142)

1 : √2 is the only ratio whose shape stays the same when folded in half.

That is why enlarging an A4 document to A3 does not distort its proportions. It is also why margins rarely end up lopsided when you enlarge or reduce.

When a sheet is halved, any fraction under 1mm is dropped. As the table shows, the short side of A1 is 0.5mm smaller than half the long side of A0.

How is the B series of paper sizes defined?

Japan's B series (JIS) sets the area of B0 to 1.5m². Its ratio is 1 : √2, the same as the A series.

Checking with the dimensions of B0 gives 1030 × 1456 = 1,499,680mm². That is almost 1.5m².

For the same number, a B size has 1.5 times the area of the A size. In side length that is √1.5 times, or about 1.22 times.

This rule is why enlarging A4 to B4 takes about 122%.

The B series has long been used in Japan. As the use column in the list shows, it is still common for notebooks, weekly magazines and hardcover books.

How does the ISO B series differ from the JIS B series?

The ISO B series sits between two neighbouring A sizes. It is slightly smaller than the JIS B series.

ISO 216 sets each B size by multiplying the sides of two A sizes and taking the square root (the geometric mean). For B5 and B4 the comparison is as follows.

ISO B5 and JIS B5 differ by about 6mm in width and 7mm in height. You can feel the difference in your hand.

The trouble comes when you pick "B5" in software or on a printer made outside Japan. If it means ISO B5, the margins shift when you print on JIS B5 paper.

When you choose B5 or B4 from a software paper list, check for "JIS" in the parentheses. Japanese software sometimes labels the two separately by naming the standard.

How do North American paper sizes differ?

North American paper sizes are defined in inches, and their ratio is not 1 : √2. The main ones are Letter, Legal and Tabloid.

Source: JIS P 0138, ISO 216, ANSI/ASME Y14.1

As the table shows, the inch column has round numbers. The mm column is the inch value multiplied by 25.4.

The US drawing standard (ASME Y14.1) calls the size equal to Letter "A size". The size equal to Tabloid is "B size". These have nothing to do with Japan's A and B series.

The aspect ratio varies from size to size.

• Letter: 11 ÷ 8.5 ≈ 1.29
• Legal: 14 ÷ 8.5 ≈ 1.65
• Tabloid: 17 ÷ 11 ≈ 1.55

Because the ratios are not the same, enlarging or reducing between North American sizes leaves margins.

What Japanese newspapers call "tabloid size" is a different size from the Tabloid in the table. When ordering printing, give the size in mm.

The finer differences between Letter and A4 are explained in the difference between Letter size and A4.

What are the paper sizes for photos, postcards and business cards?

Photos, postcards and business cards have sizes fixed for each use, separate from the A and B series. The dimensions are in the table below.

Source: Japan Post domestic postal terms, Art. 21 / Fujifilm, multifunction printer photo prints (L and 2L are customary, not formal standards) / Customary business card size in Japan (not a formal standard; may differ by a few mm)

The L-size and 2L-size photo dimensions come from inches.

• L-size: 3.5 × 25.4 = 88.9 → 89mm, 5 × 25.4 = 127mm
• 2L-size: 5 × 25.4 = 127mm, 7 × 25.4 = 177.8 → 178mm

The postcard is the size of Japan Post's postal postcard. It is the same height as A6 and slightly narrower than A6.

If you print data made for A6 on a postcard, the left and right edges get slightly cut off or the page is reduced. Make postcard data at the postcard's dimensions.

Business cards are shown in landscape, as in the table. This is the size commonly used in Japan, and it differs from business cards abroad.

Photo sizes are covered in detail in L-size photo dimensions, and postcards in postcard size.

How do the sizes in the list match everyday items?

Many everyday paper products are close to one of the A or B sizes. The table gives a rough guide.

"Around" in the table means that many items are not exactly the standard size. Books and magazines use formats set by each publisher.

Some notebooks are labelled "semi-B5". This name is used for notebooks made slightly smaller than B5, so their size differs from standard B5.

When you need exact dimensions, use a ruler rather than the size name.

What paper sizes can you print at a convenience store?

Convenience store copiers mainly print on A4, A3, B5, B4, postcards and photo paper. The sizes you can use vary by service.

As an example, here are the specifications of Fujifilm's Netprint, a service for printing on Seven-Eleven copiers.

• Printable paper: A4, A3, B5, B4, postcards, and L-size and 2L-size (photo paper)
• Originals you can register: from A2 at the largest to A7 at the smallest
• "Slightly smaller" setting: prints slightly smaller so the edges are not cut off

An original in a size that is not among the printable papers, such as Letter, is printed fitted to the paper you choose. You can check the enlargement and reduction ratios in the scaling section below.

Other convenience stores offer different papers and use different names for the settings. Check each service's guide before using it.

How do you choose from the paper size list by use?

Choose a paper size by how far away the reader is and how it will be stored or sent. The table gives a rough guide.

If in doubt, match the tools the recipient has at hand (files, printer, envelopes).

Poster sizes are compared in poster sizes.

Which paper size fits which envelope?

A4 folded in three fits a Nagagata No. 3 envelope, and unfolded it fits a Kakugata No. 2 envelope. The table shows which paper fits each envelope.

Source: Japan Post, Envelopes conforming to JIS S 5502:2010 (size); Japan Post rate table (mail class) / JIS S 5502, Japan Post mail size classes / Customary size used by envelope makers (not in the JIS S 5502:2010 size table)

Japan Post's standard-size mail is 14 to 23.5cm long and 9 to 12cm wide, up to 1cm thick and 50g in weight. "Standard" in the table means an envelope within this range.

What ratio do you use to enlarge or reduce paper sizes?

Work out the ratio for width and for height, and use the smaller one. One step within the same series is about 141% or about 71%.

There is just one formula.

• Ratio = target side ÷ original side (work it out for both width and height)

When the width and height ratios differ, choosing the smaller one keeps the page from spilling over. If you match the larger one, the other side runs off the paper.

The ratio shown on a copier is this value rounded to a whole number. Depending on the model, the display may differ by about 1%.

Keep area and side length apart, too. A3 has twice the area of A4, but its sides are only about 1.41 times as long.

What are common mistakes with the paper size list?

The most common one is mixing up the ISO and JIS versions of a B size with the same name. Other mistakes are in the table below.

The key point: give the mm dimensions along with the paper name, rather than the name alone, to avoid mix-ups.

What terms appear in the paper size list?

The terms you will meet when reading the paper size list are in the table below.

The dimensions in the list are finished sizes, which differ from the size of the paper before printing.

What else should you know along with the paper size list?

Along with the paper size list, knowing pixel counts and paper thickness gets you fully ready to print.

How do you find a paper size in pixels?

Once you choose the dpi, the pixel count of a paper size is fixed. Values for common sizes are in the table below.

Source: JIS P 0138, ISO 216, ANSI/ASME Y14.1

For data sent to a print shop, use the 300dpi column as a guide. If you only view it on screen, fewer pixels are enough.

How the calculation works is explained in A4 size in pixels.

How can you keep the paper size chart as a PDF?

Print this page from your browser and choose "Save as PDF" as the destination. This saves the chart as a PDF.

The table is wide, so it is easier to read if you set the paper to landscape in the print settings. If the table gets cut off, lower the scale before saving.

Does the paper size list tell you the paper thickness?

No. The paper size list shows size only, and paper thickness is given by a different number.

Paper thickness is expressed as weight per square metre (grammage, g/m²). Print orders also use the weight of 1,000 sheets of base paper (ream weight, kg).

Even at the same A4 size, a different thickness changes how the paper feels and how much it weighs for postage.

Frequently asked questions about paper sizes

Which paper size is the most common?

A4 is the most common size for office documents and copy paper.

Files, envelopes and copiers are all built around A4. If in doubt, make it A4 and use A3 only for large documents.

Which is bigger, A3 or B4?

A3 is bigger.

As the list shows, A3 is longer in both width and height. B4 is bigger than A4 and smaller than A3.

What is the difference between A5 and B5?

B5 is bigger. A5 is half of A4, and B5 is half of B4.

Notebooks are often B5, while planners and booklets are often A5. Check the exact dimensions in the list.

What is the largest paper size?

In this list, B0 is the largest, with about 1.5 times the area of A0.

It is used for large posters and drawings. Everyday printing rarely goes beyond A3 or B4.

How many centimetres is A4?

See the cm column of the list. Divide the mm value by 10 to get cm.

Centimetres give decimals, so give sizes in mm when ordering printing.

Which sizes in the list can be printed at a convenience store?

Many convenience stores can print A4, A3, B5, B4, postcards and photo paper.

North American sizes such as Letter often cannot be selected. Check each service's guide before using it.

Sources

• ISO 216:2007 Writing paper and certain classes of printed matter. Trimmed sizes. A and B series (ISO)
• JIS P 0138 Trimmed sizes of processed paper (Japanese Industrial Standards Committee, JIS search; in Japanese. Finished sizes of the A and B series)
• Y14.1 Drawing Sheet Size and Format (ASME)
• CSS Values and Units Module Level 3: Absolute lengths (W3C)
• Postcards (Japan Post, in Japanese. Postcard dimensions)
• First-class and second-class mail rates (Japan Post, in Japanese. Size, thickness and weight limits for standard-size mail)
• Netprint specifications (Fujifilm Business Innovation, in Japanese. Printable paper: A4, A3, B5, B4, postcards, L-size and 2L-size)