Most people run into A9 on a sticker sheet or a coupon, and the size they need is 37 x 52 mm (3.7 x 5.2 cm, or 1.46 x 2.05 in). It sits second from the bottom of the ISO 216 A series, just above A10.
Cut an A8 sheet in half and you get two of these. The 1:1.414 ratio carries over from every other A size, so a design built at A9 scales up to A4 without the proportions shifting. Printers use the format for stickers, labels, coupons and tickets.
There’s a catch with the name. It also belongs to a US envelope that measures 5.75 x 8.75 in, about 4 times the width and height of the ISO sheet (4over4, 2026).
Write the millimeters on any spec and name the standard, or you may end up ordering the wrong one.
What Size Is A9 Paper?
The width comes first when you quote it, so A9 paper measures 37 x 52 mm (3.7 x 5.2 cm, or 1.46 x 2.05 in).
It’s a trimmed sheet format from the ISO 216 A series, one step up from the smallest size, A10.
- 37 x 52 mm, the value ISO 216 defines
- 3.7 x 5.2 cm
- 1.46 x 2.05 in
- 105 x 147 pt, at 72 points per inch
The millimeter figure is the one the standard publishes, and it belongs to the wider family of international paper sizes used for stationery, cards and forms. Everything else above is converted from it.
Inch values differ between sources. Helloprint and Adobe’s A9 guide round to 1.5 x 2.0 in, while dimensions.com lists 1.46 x 2.05 in.
They describe the same sheet. The exact conversion is 1.457 x 2.047 in. On a supplier spec, just write the millimeters and skip the inch debate.
How Many Pixels Is A9 at 300 DPI?
At 300 DPI, A9 comes to 437 x 614 pixels. Drop to 72 PPI and it shrinks to 105 x 147 pixels.
| Resolution | Pixels (width x height) | Note |
|---|---|---|
| 72 PPI | 105 x 147 | Screen preview only |
| 150 PPI | 219 x 307 | Calculated from 37 x 52 mm |
| 200 PPI | 291 x 409 | Listed in Adobe’s A9 guide |
| 300 PPI | 437 x 614 | Print standard (Adobe, Helloprint) |
To work it out yourself, divide the millimeters by 25.4 and multiply by the resolution. At 300 PPI that’s 37 / 25.4 x 300 = 437 and 52 / 25.4 x 300 = 614.
A millimeter to pixel converter does the same math for other formats.
People swap DPI and PPI all the time. Strictly, PPI counts image pixels while dots per inch counts printer dots, and Photoshop’s documentation sets print resolution in pixels per inch.
Resolution is where small formats trip people up.
A 105 x 147 file holds 15,435 pixels. A canvas built at 437 x 614 holds 268,318.
Photoshop’s Resample option will add pixels to a small file, but Adobe’s help pages note that resampling changes image quality. Start at 437 x 614 instead of upscaling a screen mockup.
How Does ISO 216 Produce A9 From the A Series?
ISO 216 starts with A0 at 1 square meter and halves the sheet nine times along its longer side. After rounding to whole millimeters, that leaves A9 at 37 x 52 mm.
Every cut keeps the 1:1.414 aspect ratio, which makes A9 a scaled copy of A4 and A0.
Aspect ratio and halving
Only one rectangle keeps its shape when you cut it in half, and that’s one with sides in the ratio of 1 to the square root of 2.
Georg Christoph Lichtenberg described the idea in a letter to Johann Beckmann dated 25 October 1786, according to the copy hosted by Markus Kuhn at the University of Cambridge.
On paper the ratio is 1.414. A9 lands at 1.405 once it’s rounded (52 / 37).
The cut runs across the longer side, so a 52 x 74 mm sheet splits into two 37 x 52 mm sheets. Go from A4 down to A9 and you’ve made five halvings, which means 32 A9 sheets per A4 sheet.
A9 next to A8 and A10
Cut a 52 x 74 mm A8 sheet across its longer side and you get two A9 sheets.
| Size | Millimeters | Area | Relation to A9 |
|---|---|---|---|
| A7 | 74 x 105 | 77.70 sq cm | Cuts into 4 A9 |
| A8 | 52 x 74 | 38.48 sq cm | Cuts into 2 A9 |
| A9 | 37 x 52 | 19.24 sq cm | Reference size |
| A10 | 26 x 37 | 9.62 sq cm | Half of A9 |
Halve an A9 and you get two 26 x 37 mm A10 sheets, the smallest format in the series.
Area and rounding
A9 covers 1/512 of A0. That would be 19.53 square centimeters if the standard kept every digit.
The published 37 x 52 mm sheet covers 19.24 square centimeters instead. That’s about 1.5% under theory for A8, A9 and A10, according to papersizes.org, and far less at the larger sizes.
The reason is simple enough. One millimeter is a bigger share of a 37 mm edge than of an 841 mm edge. Unrounded, A9 would be roughly 37.16 x 52.56 mm.
Standard, origin and tolerance
ISO’s catalogue lists ISO 216:2007 as the current edition, reviewed and confirmed in 2021.
The system itself traces back to DIN 476, published on 18 August 1922 (DIN), which Walter Porstmann built on Lichtenberg’s ratio.
- ISO 216 allows plus or minus 1.5 mm for dimensions up to 150 mm (papersizes.org)
- DIN 476 is tighter, at plus or minus 1 mm over the same range (Markus Kuhn, University of Cambridge)
In practice, a sheet cut to ISO tolerance can measure anywhere from 35.5 to 38.5 mm wide. For tight die-cut work, ask the printer which tolerance applies.
What Is A9 Paper Used For?
Small stickers, labels, coupons and tickets cover most of it, according to Helloprint and Adobe’s A9 guide.
Stickers are the main job, mostly standard, roll and doming types (Helloprint). Helloprint also calls the size a good fit for coupons and tickets, and Adobe’s guide lists labels next to coupons and small stickers.
Low production cost is the big appeal, and both Adobe and Helloprint point to it. The downside is space. Adobe puts the printing surface at roughly half a business card, which is too small for anything text-heavy.
With room for a short message only, type choice carries the design. Sturdy label fonts hold up better at this size than thin ones.
Gift tags are where A9 isn’t the obvious pick. Avery’s printable tags measure 89 x 50 mm and run 10 to an A4 sheet, which is more than twice the area of A9 (4,450 vs 1,924 sq mm).
A9 works for a small tag with a logo. A tag that needs a punched hole, a name and a message wants the larger format.
How to Set Up an A9 Document in Design Software
Set the page to 37 x 52 mm and add 3 mm of bleed on every side. Raster content should be built at 300 PPI.
- Create the document at trim size, with units set to millimeters.
- Add 3 mm of bleed on all four sides. Adobe’s InDesign help calls 0.125 in (3 mm) standard, though some print providers ask for more.
- Set raster resolution to 300 PPI. With the 43 x 58 mm bleed canvas, that is 508 x 685 px.
- Choose the color mode the printer asks for.
- Run backgrounds and images to the bleed edge. Keep text and logos well inside the trim line.
- Export a PDF with crop marks and the document bleed settings.
Step 4 has no single answer. Adobe’s Illustrator tutorial picks CMYK for print, while contributors on Adobe’s Photoshop forum argue there is no generic CMYK and that the printer’s profile decides.
| Tool | Where to set it | Watch for |
|---|---|---|
| Photoshop | File > New, millimeters, 300 pixels/inch | Bleed goes into the canvas size |
| Illustrator | File > New, Bleed fields, Raster Effects 300 ppi | Color mode follows the printer |
| InDesign | File > New > Document, Bleed and Slug panel | Bleed can be added later in Document Setup |
| Word | Size > More Paper Sizes, Paper tab | Printer driver must accept the size |
| Figma | Frame width and height in pixels | PDF export maps 1 px to 1/72 in |
Bleed hits A9 harder than any larger sheet. Three millimeters of bleed per side grows the canvas from 1,924 to 2,494 sq mm, about 30%, against roughly 5% on A4.
Check the supplier’s spec before building the file. Adobe’s InDesign help notes that some providers want more than 3 mm.
Figma has its own quirk. A September 2023 thread on Figma’s community forum reports a 3900 x 5700 px frame opening at 54 x 79 in after a 1x PDF export, which works out to one pixel per 1/72 inch.
At that ratio, a 437 x 614 px A9 frame exports at about 154 x 217 mm. Figma is fine for A9 mockups. For the final file I’d use Illustrator or InDesign, since both hold millimeters natively.
For the handoff, Adobe’s workflow is to choose Marks and Bleeds and tick Use Document Bleed Settings. That gives you a print-ready file with crop marks and bleed intact.
When A9 Paper Size Causes Problems
Desktop printers won’t take A9, and the name collides with a US envelope size. Then there’s the plain fact that 37 x 52 mm leaves very little room for content.
Printers reject it
HP lists a 76.2 x 127 mm minimum custom size for the ENVY 5055, and a reply on Canon’s support community gives 3.5 x 5 in for the iP8720.
| Printer | Minimum size | Against A9 |
|---|---|---|
| HP ENVY 5055 | 76.2 x 127 mm | 2.1x wider, 2.4x taller |
| Canon iP8720 | 89 x 127 mm (3.5 x 5 in) | 2.4x wider, 2.4x taller |
| Epson SureColor P5370 | 203 x 254 mm | 5.5x wider, 4.9x taller |
Canon’s reply says the printer refuses smaller sizes to avoid feeding problems. The Epson figure comes from the manufacturer’s own FAQ, published in January 2024.
The workaround is to print on an A4 sheet and trim. With 3 mm bleed on every side, 20 A9 pieces fit on one A4 sheet, not the 32 of a bleed-free layout, and that’s before crop marks and printer margins.
The envelope clash
Two different things carry the A9 label.
The ISO version is the 37 x 52 mm trimmed sheet defined by ISO 216.
The US A9 envelope is another thing entirely. It measures 5.75 x 8.75 in (about 146 x 222 mm) and takes cards up to 5.5 x 8.5 in, per 4over4.
That makes the envelope about 4 times the width and height of ISO A9, and it sits closer to A5 than to A9. Some size databases list the same envelope as A9 Diplomat.
On any order, quote millimeters and say “ISO A9” or “A9 envelope”.
Content limits
Helloprint notes that writing on A9 by hand is impractical, and that the surface holds only a couple of small, bold text lines.
Think of A9 as a trim size more than a printing size, because the sheet it prints on is bigger.
A9 Paper Size FAQ
How much does an A9 sheet weigh?
An A9 sheet at 80 GSM weighs about 0.15 g. Multiply the paper weight by the area, so 80 g per square meter times 0.001924 square meters gives 0.154 g.
Thicker stock scales in a straight line. A 300 GSM sheet comes to about 0.58 g.
How many points and picas is A9 paper?
It comes to 105 x 147 points, or 8.74 x 12.28 picas.
Both values come from the 37 x 52 mm trim size, at 72 points per inch and 12 points per pica.
What are the perimeter and diagonal of A9?
The perimeter is 178 mm (17.8 cm). The diagonal is about 63.8 mm, calculated from 37 and 52 mm with the Pythagorean theorem.
That diagonal is the longest straight line across the sheet, which matters for die-cut shapes.
Is A9 portrait or landscape?
Portrait is the standard way to quote it, at 37 mm wide and 52 mm tall. Rotate the sheet 90 degrees and you have landscape at 52 x 37 mm.
Sources disagree on the order. Pixartprinting’s table writes 52 x 37 mm, while papersizes.io writes 37 x 52 mm, so confirm which edge is the width with the supplier.
When a Layout Outgrows A9
A layout outgrows A9 paper size once it needs a second text block, and A8 at 52 x 74 mm is the next step up.
Test the layout at 37 x 52 mm first. Move to A8 only when that second text block won’t fit, and confirm bleed and trim tolerance with the printer before you order anything.
Starting at A9 keeps paper cost lowest, so a failed fit costs the least there.
The upgrade does carry a price. A8 doubles the area to 3,848 sq mm, but with 3 mm bleed an A4 sheet holds 10 A8 pieces against 20 A9 pieces, so paper per piece doubles.
If A8 still feels tight, the 74 x 105 mm A7 sheet doubles the area again.
Renowned for his expertise in logo design and visual branding, Bogdan has developed a multitude of logos for various clients.
His skills extend to creating posters, vector illustrations, business cards, and brochures. Additionally, Bogdan's UI kits were featured on marketplaces like Visual Hierarchy and UI8.
He also wrote in the past years on sites like Design Your Way, WebDesignerDepot, WPDean, Designmodo, Speckyboy, Slider Revolution, and more.
- The Windsurf Logo History, Colors, Font, And Meaning - 10 October 2026
- How to Remove Background From Product Photos (No Photoshop) - 10 October 2026
- How Designers can Build a Stronger Online Creative Identity - 9 October 2026
Bogdan Sandu is a seasoned designer who has been designing websites since 2008. Renowned for his expertise in logo design and visual branding, Bogdan has developed a multitude of logos for various clients. His skills extend to creating posters, vector illustrations, business cards, and brochures. Additionally, Bogdan's UI kits were featured on marketplaces like Visual Hierarchy and UI8. He also wrote in the past years on sites like Design Your Way, WebDesignerDepot, WPDean, Designmodo, Speckyboy, Slider Revolution, and more.
You Might Also Like
