Poster Sizes Explained: A Simple Guide for Etsy & Print-on-Demand Sellers
If you’re selling posters online — especially through Etsy or print-on-demand — understanding poster sizes is essential. Customers across the UK, EU, USA, Canada, and Australia all use different sizing systems. When you understand these systems (and offer the right ones), your shop instantly feels more professional and trustworthy.
This guide breaks everything down simply: A-sizes → Inch sizes → Aspect ratios → EU↔US conversions.
📏 The Two Main Poster Size Systems
There are only two systems you need to understand:
1. A-Sizes (ISO Standard) — Used Across UK & EU
A4, A3, A2, A1, A0. These sizes scale perfectly: each size is exactly double the next.
2. US Inch Sizes — Dominant on Etsy Worldwide
8×10", 11×14", 16×20", 18×24", 24×36". These ratios vary but are extremely popular, even outside the US.
If you want to maximise search visibility, you should offer both.
📐 A-Sizes (EU / International)
| Size | Centimetres | Inches |
| A5 | 14.8 × 21 cm | 5.8 × 8.3" |
| A4 | 21 × 29.7 cm | 8.3 × 11.7" |
| A3 | 29.7 × 42 cm | 11.7 × 16.5" |
| A2 | 42 × 59.4 cm | 16.5 × 23.4" |
| A1 | 59.4 × 84.1 cm | 23.4 × 33.1" |
| A0 | 84.1 × 118.9 cm | 33.1 × 46.8" |
A-sizes are essential for UK & EU customers because frame stores universally stock them.
📐 US Inch Sizes (Etsy Standard)
| Size | Inches | Centimetres |
| 5×7" | 5 × 7 | 13 × 18 |
| 8×10" | 8 × 10 | 20 × 25 |
| 11×14" | 11 × 14 | 27 × 35 |
| 12×16" | 12 × 16 | 30 × 40 |
| 11×17" | 11 × 17 | 28 × 43 |
| 12×18" | 12 × 18 | 30 × 45 |
| 16×20" | 16 × 20 | 40 × 50 |
| 18×24" | 18 × 24 | 45 × 60 |
| 24×36" | 24 × 36 | 60 × 90 |
🌍 Why EU & US Sizes Don’t Convert Perfectly
Europe and the US use completely different aspect ratios:
-
🇪🇺 EU sizes: round-number cm + A-series
-
🇺🇸 US sizes: inch ratios like 4:5, 3:4, 2:3
This means an A3 is not the same shape as 11×14", and an A2 is not the same as 16×24". Printers use the closest regional equivalent — not an exact mathematical conversion. This is the industry standard for how PrintShrimp and IKEA frames pair sizes.
📦 EU ↔ US Poster Size Equivalents (Frame-Friendly Matches)
| EU (cm) | US (inch) |
| 21×29.7 cm | A4 |
| 29.7×42 cm | A3 |
| 42×59.4 cm | A2 |
| 59.4×84.1 cm | A1 |
| 20×25 cm | 8×10" |
| 30×40 cm | 12×16" |
| 40×50 cm | 16×20" |
| 45×60 cm | 18×24" |
| 60×90 cm | 24×36" |
🎨 The Three Aspect Ratios Every Seller Needs
To offer every common size without redesigning everything, you only need to design in these ratios:
-
A-Ratio (A5, A4, A3, A2, A1, A0)
-
4:5 Ratio (8×10, 16×20)
-
2:3 Ratio (12×18, 24x36)
🏁 Final Recommendations for Etsy Sellers
-
⭐ Offer BOTH A-sizes and US inch sizes.
-
⭐ Include 10–12 total size options per listing.
-
⭐ Use the EU↔US pairing list for accurate variations.
-
⭐ Use PrintShrimp to print domestically for fast local delivery.
