Poster Pixel Size Calculator
A 24x36 inch image at 300 DPI has a resolution of 7200 by 10800 pixels, making it ideal for high-quality prints. This pixel count ensures sharp details and clarity, perfect for professional posters, banners, or artwork. Using this resolution on platforms like Adobe Photoshop or Illustrator allows designers to work with precise dimensions. Calculating pixels from inches and DPI helps maintain image quality when scaling or printing large-format graphics, ensuring your final product looks crisp and vibrant.
1. Pick your poster size
Orientation
2. Pixel dimensions you need
For print-ready 300 DPI:
7,200 × 10,800 px
77.8 megapixels total
3. Check your image (optional)
Poster Pixel Sizes at 300 DPI — Quick Reference
| Poster Size | Pixels (300 DPI) | Megapixels | Region |
|---|---|---|---|
| 24×36" | 7,200 × 10,800 | 77.8 MP | US |
| 18×24" | 5,400 × 7,200 | 38.9 MP | US |
| 16×20" | 4,800 × 6,000 | 28.8 MP | US |
| 12×18" | 3,600 × 5,400 | 19.4 MP | US |
| 11×17" | 3,300 × 5,100 | 16.8 MP | US |
| A1 (594×841 mm) | 7,016 × 9,933 | 69.7 MP | ISO |
| A2 (420×594 mm) | 4,961 × 7,016 | 34.8 MP | ISO |
| A3 (297×420 mm) | 3,508 × 4,961 | 17.4 MP | ISO |
When you’d use this calculator
Knowing the exact pixel dimensions of a poster sounds like a niche concern, but it shows up constantly in real workflows. These are the four scenarios where I reach for this calculator most often:
- Prepping an Etsy digital download listing. Etsy lets you upload up to 5 files per listing. For a poster design, you typically want 2:3 (24×36 master), 3:4 (18×24), and one ISO option (A2). The calculator tells you whether your source file is large enough for the largest size before you commit a design to Etsy. If it’s not, you upscale once and ship at full resolution.
- Validating a Photoshop or Illustrator export. Designers regularly export at the wrong DPI by accident — usually 72 DPI because that was the canvas default, or 150 DPI because they forgot to change Photoshop’s "Image Size" panel. Running the exported pixel dimensions through this calculator catches the mistake before the file ships.
- Checking a Printify, Printful, or Society6 upload. Each print-on-demand platform has its own minimum-pixel requirement per product. Printify wants 2,400×3,000 minimum for a poster; Society6 wants 7,632×6,480 for art prints. The calculator translates between "what they want" and "what your file is" without you having to do the inch-DPI math in your head.
- Sizing for a professional print shop order. If you’re ordering an A1 print for a craft fair booth or an art show, the print shop will quote a minimum pixel count. They almost always want 300 DPI and add a 3 mm bleed. Compute the right size before you upload — if you’re short, the print shop charges you for the rejected file.
Common pixel-sizing mistakes for posters
I’ve made every one of these at least once. Each costs you either a refund, a bad review, or an evening re-doing work. Worth the two minutes to read.
1. Forgetting bleed when the print shop requires it
Most digital downloads on Etsy don’t need bleed because the buyer prints at home. But if you’re sending a file to a professional print shop, they typically require 3 mm of extra image on each side that gets trimmed off. At 300 DPI that adds about 70 pixels per side — a 24×36 poster with bleed needs roughly 7,340×10,940 instead of the bare 7,200×10,800.
2. Copying social-media DPI to a print export
Instagram, Pinterest, and Etsy listing photos all display at 72 DPI. If your design workflow exports for social by default, it’s easy to ship a 72 DPI file to a print buyer. The image will look fine on screen and look terrible printed. Always verify the exported file’s DPI before listing.
3. Scaling up in Photoshop instead of AI-upscaling
Photoshop’s "Image Size" with "Resample: Bicubic Smoother" can technically increase pixel dimensions, but it does so by interpolating — mathematically inventing pixels by averaging neighbors. The result is soft, mushy, and visibly blurry at print size. AI upscaling adds real detail by trained inference, producing genuinely sharp larger images.
4. Mixing inches and millimeters mid-project
A US seller designing for a UK buyer can mistakenly export a 16×20 inch file when the buyer wanted A2. The pixel counts are different (4,800×6,000 vs 4,961×7,016) and the aspect ratios don’t match (4:5 vs 1:√2). Always match the format to the buyer’s region. The calculator above handles both unit systems so you can verify before exporting.
5. Ignoring the print shop’s minimum-resolution spec
Every commercial print service publishes a minimum pixel count or DPI. Many sellers skip this and discover at upload time that their file gets rejected. Check the print service’s requirements page before you start designing — it takes 30 seconds and saves a wasted afternoon.
Image too small? Ratio Ready upscales any image to print-ready dimensions in seconds — covered in our AI upscaler, poster maker, and wall art converter.
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