How to print a 24×36 poster at home
24×36 is the biggest poster most people ever print, and it's also the one that tiles most neatly onto Letter paper: three columns that land on exactly 24 inches with nothing wasted, and four rows with room to spare. Twelve sheets. This guide covers the grid, the seventeen seams you'll be taping, the resolution a 2:3 image needs at this size, how to keep it to twelve pages if the poster is landscape, and how to trim it so it drops into an off-the-shelf 24×36 frame.
24 × 36 on Letter paper is a 3 × 4 grid, twelve sheets, with the width set to 24 in and no overlap; adding a 0.25 in overlap makes it 4 × 4. Print at 100%.
On this page
Why 24×36 is the easy big one
A Letter sheet with a 0.25 in margin on every side prints an 8 × 10.5 in image area. Twenty-four inches divided by eight is exactly three, so the three columns of the grid cover the width perfectly, with no trimming on the outer edges and no partial column. The height doesn't divide as cleanly: 36 ÷ 10.5 is 3.43, so you need four rows, and four rows cover 42 in. The extra six inches all sit in the bottom row, which is mostly blank. That's expected, not a mistake, and it's the reason the overlap you'll turn on in a minute doesn't cost you a fifth row.
Set the width to 24 in in Free Image Splitter and the tool arrives at the same 3 × 4 grid on its own; the preview shows the cut line where the image ends in the last row. If you'd rather think in pages, setting three pages across gets you there too.
Is your image the right shape?
24×36 is a 2:3 rectangle, and that ratio decides how much of your picture survives. A few common sources:
| Source | Ratio | What happens at 24×36 |
|---|---|---|
| DSLR or mirrorless photo | 3:2 | Fits exactly in landscape; rotate the poster to 36×24 and nothing is cropped. |
| Phone photo | 4:3 or 3:4 | About 11% of the long edge is cropped. Decide which end goes before you split. |
| Midjourney / DALL·E portrait output | 2:3 | Fits exactly. Resolution, not shape, is the problem — see below. |
| Canva "Poster" template (18×24) | 3:4 | Cropped like a phone photo. Better to resize the design to 24×36 in Canva first. |
| Square (Instagram) | 1:1 | A third of one dimension goes. Print it as 24×24 instead, which is nine sheets. |
The splitter crops centrally when the image and the target don't match. If the important part of the picture is off-centre, crop it yourself first so you control which edge is lost.
Resolution at this size
At 24 in wide, a pixel count that looked generous on screen gets thin. The DPI readout in the workspace is pixels across divided by 24, and the height has to keep up too:
| Target | Pixels needed (W × H) | Typical source that has it |
|---|---|---|
| 100 DPI — fine from across a room | 2400 × 3600 | A 12 MP phone photo, cropped |
| 150 DPI — good on a wall | 3600 × 5400 | A 24 MP camera, or a 4× upscale of AI output |
| 200 DPI — sharp at arm's length | 4800 × 7200 | A 45 MP camera, a 300 DPI Canva export, a vector PDF |
| 300 DPI — print-shop spec | 7200 × 10800 | Scans and vector files only; overkill for a wall |
A default 1024 × 1536 AI generation is 43 DPI at this size and will look like a mosaic. Run it through the upscaler at 4× to 4096 × 6144, which is 170 DPI and perfectly respectable from a metre away. The splitter never softens or resamples what you give it: whatever DPI the readout shows is what comes off the printer.
Split it
- Drop the file in and set the width to 24 in. Confirm the readout says 3 × 4 pages and 24 × 36 in assembled size.
- Read the DPI colour. Green or amber, carry on. Red, upscale or print smaller; twelve sheets of blocky poster is an expensive way to learn that.
- Margin 0.25 in, overlap 0.25 in, cut-line guides on. The overlap repeats a strip of image on the neighbouring page so a slightly off cut still meets cleanly.
- Export the PDF and print at Actual size / 100%. Print page one alone, measure the image area with a ruler, and only then send the other eleven.
Assembling seventeen seams
A 3 × 4 grid has eight vertical joints and nine horizontal ones. Taping them in the wrong order is how a poster ends up a few millimetres out of square at the far corner. The order that works:
- Build three vertical strips first. Each column is four pages and three short seams. Trim the interior edges only, lay the pages on a table, align the cut-line guides, and tape from behind.
- Trim the long inner edges of the strips. The two inside edges of the middle strip and one edge of each outer strip. Use a straightedge; these cuts are 36 in long and a wobble shows.
- Join the strips with two long seams. Tape from behind again, one continuous run each. Two long seams are easier to keep straight than twelve short ones stacked row by row.
- Trim the outside last. The outer margins have been protecting the corners all along. Cut the finished rectangle to 24 × 36 in one pass per side.
Diagrams of the trim and tape technique are in how to print a large image on a regular printer.
Landscape: keeping 36×24 to twelve pages
If the poster is 36 wide and 24 tall, don't just rotate the image and keep portrait pages: 36 ÷ 8 is 4.5, so you'd need five columns, and 24 ÷ 10.5 needs three rows, which is fifteen sheets. Switch the page orientation to landscape instead. A landscape Letter sheet prints 10.5 × 8 in, so 36 ÷ 10.5 is 3.43 → four columns, and 24 ÷ 8 is exactly three rows. Twelve pages again, with the exact division now on the height. Same grid, turned on its side.
Fitting it in a frame
24×36 frames are sold everywhere because it's a standard size, which is the main reason to print at this size rather than "roughly two feet by three". Two things to know. The frame's lip covers about 0.25 in on each side, so if your image has fine detail or text right at the edge, it'll be hidden; leave a little breathing room in the design. And the frame expects a single flat sheet: a taped poster wants a backing. Foam board comes in 24×36 for a few dollars, and mounting the poster on it with spray adhesive or double-sided tape before it goes behind the glass kills both the curl and the seam shadows. The full comparison of what to mount on is in how to make a DIY poster at home.
What twelve sheets cost
On plain paper and a typical inkjet, twelve pages run about $1.20–3.00 in paper and ink. Matte photo paper roughly doubles that and is worth it for photographs; for a movie-poster reproduction or anything graphic, plain paper looks better than you'd expect once it's behind glass. A print shop charges $15–40 for the same size. The shop's advantage is a single seamless sheet; if the poster is going in a frame, the seams are the only thing you're paying to avoid, and taped from behind they mostly disappear anyway.
When something goes wrong
The bottom row is mostly empty
Correct. Four rows cover 42 in and the poster is 36, so the last row only carries the final 4.5 in of image. Trim at the cut line. The tool always anchors the image to the top-left of the grid, so the blank space is always in the last row and last column, never split across both ends.
The three columns don't add up to 24 inches
The printer scaled the pages. Anything other than Actual size / 100% in the print dialog, or a driver option like "fit to printable area", shrinks each tile by a few percent, and across three columns that compounds into a visible shortfall. Reprint at 100% and measure page one before doing the rest.
It won't sit flat in the frame
Twelve sheets of tape on the back build up thickness at the seams. Mount the poster on foam board or mat board before framing, and if the frame is tight, use the thinner tape rather than packing tape. Mounting also stops the ripple that shows up when a taped poster is held only at its edges.
Twelve sheets, one afternoon
Set the width to 24 in, check the DPI colour, download the PDF. The splitting takes less time than reading this page did.