Birthday Poster Sizes And Printing Guide

If you've ever stood in the print line at Staples holding a USB and trying to decide between 11x17 and 18x24, this post is for you. Here is the whole sizing decision, in plain language, with the print-shop minimum dimensions for each.

The three sizes that matter

For a birthday party poster, 95% of people are choosing between three:

• 11x17 (tabloid): small, cute, sits on an easel
• 16x20 or 18x24: the standard "wall behind the cake table" size
• 24x36 (movie poster): only if it's the only decoration in a big room

Anything smaller looks like a flyer. Anything bigger feels like a tradeshow.

11x17 — when it works

Best for:

• Small parties, indoor, 10–15 guests
• Sitting on an easel near the door or on a side table
• A second poster (a "fun facts" poster next to the main one)

Doesn't work for:

• Hanging on a wall — it disappears past 6 feet of viewing distance
• Outdoor parties — too small to read

Print specs:

• Minimum file: 3300 x 5100 px (300 DPI)
• Paper: matte or satin cardstock
• Cost: $3–5 at most print shops

16x20 or 18x24 — the sweet spot

Best for:

• The wall behind the cake table or food table
• Most kid birthdays (ages 2–10)
• Backdrop for the cake-cutting photo

This is the size I print 90% of the time. Big enough to see across the room, small enough to fit on a normal wall, cheap enough to not feel precious about.

Print specs:

• 16x20 minimum file: 4800 x 6000 px
• 18x24 minimum file: 5400 x 7200 px
• Paper: matte cardstock or foam-board mount
• Cost: $7–12

24x36 — movie poster size

Best for:

• Large rooms (20+ guests)
• Outdoor parties with a backdrop
• Posters that are the only decoration

Doesn't work for:

• Most kid parties — overkill
• Anything that needs to ship — won't fit in standard envelopes

Print specs:

• Minimum file: 7200 x 10800 px
• Paper: foam-board mount basically required at this size
• Cost: $20–30

PDF vs JPG vs PNG (again)

For poster sizes specifically:

• PNG for posters with text, illustration, carved numbers — basically all kid party posters
• JPG if the file size is the issue (some upload portals cap at 25MB)
• PDF for print shops that prefer it — most will convert your PNG for you

When you upload to Staples or Office Depot's web portal, they'll show you a preview. If the preview looks pixelated, your file is too small for that print size. Step down a size.

Bleed and trim

If you want the design to go all the way to the edge of the paper:

• Add 0.125" of bleed on each side (extra design that gets cut off)
• That means an 18x24 poster needs an 18.25x24.25 design file

If you don't add bleed, you'll get a white border around the poster. Sometimes that's fine, sometimes it bugs you. For kid birthdays, the border usually doesn't matter — but if it does, mention "full bleed" when you submit the print order.

My actual recommendation

For most kid birthdays:

• 18x24, foam-board mount, $10–13 at Staples
• PNG file at 5400x7200 px or larger
• Pick it up morning-of
• Lean it against the wall behind the cake. Don't tape.

That's the whole answer. Everything else is a variation.

Keep reading

• How to make a birthday poster at home — printer settings, paper, the mistakes
• Make the poster — live preview
• Birthday party poster ideas for kids — what to put on it