How to Print Poster Size at Home or Through a Print Lab
Knowing how to print poster size separates photographers and designers who can sell their work in physical form from those who stay digital-only. Whether you’re working from a home inkjet or sending files to a lab, understanding a2 print size dimensions, print banner size specs, and megapixel print size requirements prevents wasted paper and disappointing results.
This guide covers the math behind how to print poster size on home printer settings, explains what a2 print size means in practice, walks through print banner size for large-format displays, and gives you a megapixel print size chart so you know your image file’s true limits before you hit print.
Understanding Your Size Options
Poster printing starts where standard letter and tabloid sizes end. Common poster sizes are 16×20, 18×24, 24×36, and 27×40 inches. The a2 print size comes from the ISO 216 international paper system and measures 16.5 x 23.4 inches — roughly equivalent to a standard 16×20 poster in American terms.
If you’re ordering an a2 print size for framing, note that most US frame manufacturers don’t stock A-series sizes. You’ll either need to order a custom frame or trim the print slightly to fit a standard 16×20 frame without losing any important content along the edges.
Print banner size covers a different use case entirely — banners are horizontal or vertical panels printed on vinyl, fabric, or heavy paper, typically 24 inches to 10 feet wide. A standard trade show banner runs 33×80 inches. For outdoor events, print banner size often reaches 4×8 or 4×12 feet. These require a wide-format printer or a commercial print lab, not a home inkjet.
Megapixel Print Size: What Your Camera Can Actually Deliver
Print quality depends on pixels per inch (PPI). The standard for photo-quality prints is 240–300 PPI. At 300 PPI, a 24-megapixel camera (6000×4000 pixels) produces a clean 20×13.3 inch print — just under 16×20. Scaling beyond that requires either accepting a lower PPI or upscaling in software.
Megapixel print size math: divide your image’s pixel dimensions by your target PPI. A 6000-pixel-wide file at 200 PPI prints 30 inches wide. At 150 PPI — acceptable for images viewed from 3+ feet — that same file prints 40 inches wide. For large-scale how to print poster size projects, 150 PPI is often enough because viewers stand back from large prints naturally.
If your file is underresolution, use Lightroom’s “Enhance” feature or Topaz Gigapixel AI to upscale before sending to the lab. These tools use AI interpolation that produces sharper results than the basic bicubic scaling built into Photoshop.
How to Print Poster Size on Home Printer
Most home inkjets top out at 13 inches wide — borderline for poster work. If your printer maxes at 8.5 inches, you can tile the image across multiple sheets in Photoshop using the “Tile” option under Print settings. Tape the pages together for a DIY result that works for temporary display.
For how to print poster size on home printer results above 13 inches, a wide-format inkjet like the Canon PIXMA Pro-200 or Epson SureColor P700 handles up to 13×19 inch sheets and roll paper up to 17 inches wide. These run $500–$800 new but make sense for photographers printing regularly.
Bottom line: Match your megapixel print size math to your target dimensions before ordering anything. For prints up to 24 inches, a 12–24 MP file works well at standard viewing distance. For a2 print size or print banner size orders, use a commercial lab with a calibrated wide-format printer — the cost difference is small and the consistency is far better than a home inkjet at those dimensions.