ISO vs US Print Sizes: A4, Letter, A3 Explained
A4 and Letter look almost identical on screen. In print, they have different aspect ratios — and the wrong file gives EU or US buyers white borders. Here's the complete system map.
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Quick Answer
What is the difference between ISO and US print sizes?
ISO Paper Sizes (A-Series)
Used in the EU, UK, Australia, and most of the world. Every size shares the same 1:√2 aspect ratio, so scaling between sizes never crops your artwork. A3 is exactly twice the area of A4. A4 is exactly twice the area of A5.
| Size | Inches | Pixels @ 300 DPI | Area | Common use |
|---|---|---|---|---|
| A5 | 5.83×8.27" | 1748×2480 px | 48.2 sq in | Greeting cards, small prints |
| A4 | 8.27×11.69" | 2480×3508 px | 96.7 sq in | Standard planners, wall art, EU printers |
| A3 | 11.69×16.54" | 3508×4961 px | 193.5 sq in | Posters, large wall art |
| A2 | 16.54×23.39" | 4961×7016 px | 387 sq in | Large format posters |
US Paper Sizes (ANSI)
Used primarily in the United States and Canada. Based on the imperial system — sizes do not share a common aspect ratio, so artwork does not scale cleanly between them. Most US home printers take Letter (8.5×11). Tabloid (11×17) is the standard for large-format posters.
| Size | Inches | Pixels @ 300 DPI | Area | Common use |
|---|---|---|---|---|
| Half Letter | 5.5×8.5" | 1650×2550 px | 46.75 sq in | Planners, notebooks |
| Letter | 8.5×11" | 2550×3300 px | 93.5 sq in | Home & office printers (US standard) |
| Legal | 8.5×14" | 2550×4200 px | 119 sq in | Legal documents, long-form prints |
| Tabloid | 11×17" | 3300×5100 px | 187 sq in | Posters, newspapers |
US photo sizes (4×6, 5×7, 8×10, 11×14) are separate from the ANSI office paper system — see the Etsy print sizes guide for photo frame sizes.
ISO ↔ US: Nearest Equivalents
There is no perfect cross-system equivalent. Every ISO size has a nearby US size, but they all differ in aspect ratio — a file designed for one will never fill the other cleanly.
The Whitespace Trap: Why Cross-System Files Fail
The most common complaint international Etsy sellers receive: “There are white borders when I print your file.” Almost always, this is an ISO/US mismatch.
A4 file on Letter paper (and vice versa)
Scale to fill width
A4 scaled to 8.5" wide fills Letter horizontally, but is 11.69" tall — 0.69" crops off top and bottom of your artwork.
Scale to fit height
A4 scaled to 11" tall is only 7.79" wide — 0.36" white bars appear on each side when printed on Letter.
EU and UK buyers who purchase your digital download will print at home on A4 — the standard paper that comes in every European printer box. If you only include a Letter-sized file, they will need to manually adjust their print settings or accept borders. Most won't. They'll leave a review instead.
The simple fix is to include both files: one at 2480×3508 px for A4 and one at 2550×3300 px for Letter. For posters, include both 3508×4961 px for A3 and 3300×5100 px for Tabloid.
Creating separate A4 and Letter files means two Photoshop canvases, two exports, and remembering which version is which — every time you create a new design.
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Which Sizes to Offer on Etsy
The answer depends on your audience. Here's a practical guide:
- Wall art, planners, or printable journals
- Listings with international shipping visibility
- Any category popular in the EU (art prints, home decor)
- If your shop already gets EU reviews or messages
- Large wall art (galleries, statement pieces)
- Listings targeting EU buyers explicitly
- Print-on-demand listings (Printful, Printify, SPOD EU)
- Shops that already sell A4 and want the upsell size
Practical starting point: Add A4 to every existing listing that offers Letter. Etsy allows up to 5 digital files — use slots for Letter, A4, and a combined “both sizes” PDF with instructions. EU buyers appreciate the extra file and rarely leave sizing complaints.
For more detail on individual US photo sizes, see the 8×10 vs 8.5×11 comparison — the most common confusion point for US sellers. For EU-targeted wall art specifically, the A1 print size guide covers large-format ISO sizes used by European print labs. The 300 DPI pixel chart lists exact pixel dimensions for every common size including ISO and US formats.
FAQ: ISO vs US Print Sizes
No. A4 is 8.27×11.69 inches (2480×3508 px at 300 DPI). US Letter is 8.5×11 inches (2550×3300 px at 300 DPI). A4 is 3% narrower and 6% taller. They look similar but have different aspect ratios — a file sized for one will show white borders or crop when printed on the other.
The ISO 216 system (used by most of the world outside North America) is based on a 1:√2 aspect ratio. Every size is exactly half of the next: A3 = 2× A4, A4 = 2× A5. This means you can scale artwork between ISO sizes without any cropping. The US system (Letter, Legal, Tabloid) uses different aspect ratios with no such mathematical relationship.
If you scale A4 to fill Letter width, you crop 0.35 inches from the top and bottom of your artwork. If you scale A4 to fit Letter height, you get 0.115-inch white bars on each side. Neither result is ideal for wall art or planners. You need a separate file sized correctly for each paper standard.
A4 at 300 DPI is 2480×3508 pixels in portrait orientation (8.27×11.69 inches). Landscape is 3508×2480 pixels. This is the standard pixel dimension for EU/UK print-on-demand shops, planners sold to European buyers, and most international print labs.
European buyers typically print on A4 — it is the standard home printer paper across the EU and UK. US buyers use Letter (8.5×11). If you only offer Letter files, EU buyers will experience white borders or cropping. Offering both A4 and Letter versions dramatically reduces buyer complaints from international customers.
The nearest US size to A3 (11.69×16.54 inches) is Tabloid (11×17 inches). They are close but not the same — A3 is 6% narrower and 3% shorter. A file designed for A3 placed in an 11×17 frame will show white bars on the sides. For large posters, always size your file to match exactly what your buyer will print on.
No. A4 (1:1.414 ratio) and Letter (17:22 = 1:1.294 ratio) have different aspect ratios. A single file cannot fill both without borders or cropping. The correct approach is to offer two separate files — one at 2480×3508 px for A4 buyers and one at 2550×3300 px for Letter buyers.