Poster Sizes & Aspect Ratios Explained
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.
Let’s get started 👇
📏 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 |
| 6×8" | 6 × 8 | 15 × 20 |
| 8×10" | 8 × 10 | 20 × 25 |
| 10×10" | 10 × 10 | 25 × 25 |
| 11×14" | 11 × 14 | 27 × 35 |
| 12×12" | 12 × 12 | 30 × 30 |
| 12×16" | 12 × 16 | 30 × 40 |
| 16×16" | 16 × 16 | 40 × 40 |
| 11×17" | 11 × 17 | 28 × 43 |
| 12×18" | 12 × 18 | 30 × 45 |
| 16×20" | 16 × 20 | 40 × 50 |
| 18×18" | 18 × 18 | 45 × 45 |
| 18×24" | 18 × 24 | 45 × 60 |
| 20×20" | 20 × 20 | 50 × 50 |
| 20×28" | 20 × 28 | 50 × 70 |
| 24×32" | 24 × 32 | 60 × 80 |
| 24×36" | 24 × 36 | 60 × 90 |
| 28×40" | 28 × 40 | 70 × 100 |
| 30×40" | 30 × 40 | 75 × 100 |
These are the most searched poster sizes on Etsy.
🌍 Why EU & US Sizes Don’t Convert Perfectly
This is crucial.
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"
- 👉 A2 is not the same as 16×24"
- 👉 50×70 cm is not the same as 20×28"
So printers use the closest regional equivalent — not an exact mathematical conversion.
This is the industry standard, and exactly how PrintShrimp, IKEA frames, and US framing stores pair sizes.
📦 EU ↔ US Poster Size Equivalents (Frame-Friendly Matches)
| EU (cm) | US (inch) |
|---|---|
| 70×100 cm | 28×40" |
| 75×100 cm | 30×40" |
| 84×119 cm | A0 |
| 13×18 cm | 5×7" |
| 15×20 cm | 6×8" |
| 14.8×21 cm | A5 |
| 20×25 cm | 8×10" |
| 25×25 cm | 10×10" |
| 21×29.7 cm | A4 |
| 30×30 cm | 12×12" |
| 27×35 cm | 11×14" |
| 35×35 cm | 14×14" |
| 30×40 cm | 12×16" |
| 40×40 cm | 16×16" |
| 29.7×42 cm | A3 |
| 28×43 cm | 11×17" |
| 30×45 cm | 12×18" |
| 45×45 cm | 18×18" |
| 40×50 cm | 16×20" |
| 50×50 cm | 20×20" |
| 42×59.4 cm | A2 |
| 40×60 cm | 16×24" |
| 45×60 cm | 18×24" |
| 50×70 cm | 20×28" |
| 60×80 cm | 24×32" |
| 59.4×84.1 cm | A1 |
| 60×90 cm | 24×36" |
These are frame-friendly equivalents, not exact conversions — and this is exactly what customers expect.
🎨 The Three Aspect Ratios Every Seller Needs
To offer every common size, you only need to design in these ratios:
- A-Ratio (A5, A4, A3, A2, A1, A0)
- 4:5 Ratio (8×10, 16×20)
- 12:16 / 3:4 Ratio (18×24, 24×32)
Design in these three ratios and you can export every major size.
🖨 PrintShrimp Poster Sizes
PrintShrimp prints all major EU and US sizes across all regions:
- ✔ A-sizes
- ✔ Inch sizes
- ✔ Square sizes
- ✔ Large formats
- ✔ All available in matte, satin, or gloss
- ✔ Same price for every paper finish
This makes it extremely easy to offer every option customers expect.
🏁 Final Recommendations for Etsy Sellers
- ⭐ Offer BOTH A-sizes and US inch sizes
- ⭐ Include at least 10–12 total size options
- ⭐ Design your artwork in multiple aspect ratios
- ⭐ Use the EU↔US size pairing list for accurate listing variations
- ⭐ Use PrintShrimp to print domestically for fast local delivery
This makes your shop look professional, accessible, and complete.