A home printer only takes Letter or A4 paper, but that does not limit you to small prints. If you split a picture into a grid, print each piece on its own sheet and join them, you get a poster as big as you want. It is called tiling, and it is how people make birthday banners, classroom posters and wall art without a print shop.
The quick way: a free online poster maker
The Home Print Kit poster maker does the splitting for you and works in any browser, on a computer or a phone. Your picture is processed on your own device and is not uploaded anywhere.
- Open the poster maker and choose your picture.
- Pick your paper (US Letter or A4) and how many sheets wide the poster should be. The preview shows the grid and the final size in inches and centimeters.
- Keep the overlap at 0.25 in (6 mm). It makes joining the pages much easier.
- Download the PDF. The first page is an assembly guide with a small map of the grid.
- Print the PDF at Actual size or 100%.
Each page is labeled like a map: letters for columns and numbers for rows, so A1 is the top-left corner and B1 is the page to its right.
The setting that ruins most posters: scaling
Almost every print dialog shrinks pages a little by default to make them fit the printable area. On one sheet you never notice, but across a poster the pieces stop lining up and every seam is a few millimeters off. Before printing, find the scaling option and set it to 100%:
- Chrome or Edge: open More settings, choose Scale: Custom and type 100, rather than "Fit to printable area".
- Adobe Acrobat Reader: Page Sizing & Handling, then Actual size.
- Mac Preview: Scale: 100%, and untick "Scale to fit".
Also check the paper size in the print dialog. A4 pages printed on Letter paper (or the reverse) get cropped or shrunk.
Other ways to do it
Paint on Windows
Open the picture in Paint, go to File, Print, Page setup, and under Scaling choose "Fit to" with the number of pages across and down, for example 3 by 3. Paint has no overlap and no cut marks, so you have to trim the pages edge to edge, which is harder to get straight.
Adobe Acrobat Reader
If your picture is already a PDF, Acrobat Reader can tile it: in the print dialog choose Poster under Page Sizing & Handling, then set the Tile Scale, the overlap, and tick Cut marks and Labels. You need to turn the picture into a PDF first, and you can only set the size by percentage.
Your printer's own software
Some Canon, Epson and HP printer drivers include a poster or tiling layout in their print settings. Look for words like Poster, Tiling or Multi-page under Layout or Page Setup. Where it exists it works well, but it is tied to that printer and computer.
How to put the pages together
You need scissors or a craft knife with a metal ruler, and tape or a glue stick. A cutting mat helps but is not essential.
- Lay out all the pages face up in order, using the labels.
- On every page except those in the last column, trim the right-hand white border along the cut marks. On every page except those in the bottom row, trim the bottom border.
- Join each row first: lay the trimmed edge of A1 over B1 so the picture overlaps, line up the detail, and tape it from the back.
- Then join the rows to each other the same way.
- Trim the outside border last if you want a clean edge.
For a wall, removable mounting putty or washi tape is enough. For a sturdy poster, glue the pieces onto a sheet of foam board or poster board.
Paper and printer tips
- Print all the pages in one go on paper from the same pack, so the colors match from sheet to sheet.
- Matte paper hides the seams better than glossy photo paper, which also reflects light on a wall.
- Heavier paper (24 to 32 lb, or 90 to 120 g/m²) curls less when the ink is heavy.
- For a big dark picture, a dot (halftone) poster uses far less ink and still looks great from across the room.
Common problems
The pieces do not line up. The pages were scaled when printing. Print again at 100% or Actual size.
There are thin white lines at the joins. Some of the white border was left on. Trim right up to the cut marks, or use the overlap and lay one page over the next.
Colors change from page to page. The ink ran low in the middle of the job, or different paper was used. Print the remaining pages after replacing the cartridge, on the same paper.
The picture looks blurry. The picture does not have enough pixels for that size. See what resolution you need for a big print.