Tool
Poster split calculator
Print a large poster on a normal home printer by tiling it across A4 or US Letter sheets. Pick your target size and the calculator works out the grid, the sheet count and the overlap — then assemble with tape from the back.
Result
12 sheets
- Grid
- 4 × 3
- Tile orientation
- portrait
- Printable per tile
- 200 × 287 mm
- Coverage per inner tile
- 190 × 277 mm
Tiling preview
Dashed lines are tile joints. Each joint hides a 10 mm overlap.
Assembly in four steps
1 · Print at 100 %
Use your PDF reader's Poster / Tile mode with scale at 100 % (never "Fit"). Verify the first sheet with a ruler before printing the rest.
2 · Trim the overlaps
On every tile except the left column, trim the left white margin up to the printed edge. Same for the top margin on every row except the first.
3 · Align on a flat surface
Work row by row, overlapping each trimmed edge onto its neighbour's printed overlap zone until the image lines up seamlessly.
4 · Tape from the back
Hold each joint with small tape tabs first, check alignment from the front, then run full-length tape along every joint on the back.
Frequently asked questions
How does poster tiling work?
The poster is divided into a grid of tiles, each printed on a normal sheet (A4 or Letter) with a small overlap between neighbouring tiles. After printing, you trim the overlap off one edge of each inner tile, align the sheets on a flat surface and join them with tape from the back.
Why do I need an overlap?
Home printers cannot print to the paper edge and cutting is never perfectly straight. The overlap (10 mm by default) gives you a printed margin to align against, so small trimming errors disappear inside the joint instead of leaving white gaps.
How do I actually print each tile?
The easiest route is a PDF reader with a "Poster" or "Tile" print mode — most major PDF readers have one under Print → Page Sizing. Set the tile scale to 100%, enable overlap, and the reader splits the pages automatically. This calculator tells you what grid and sheet count to expect so you can sanity-check the reader's preview.
What is the best overlap value?
10 mm suits most home printers. If your printer has unusually wide unprintable margins (check its spec — some are 5 mm or more per edge), increase the overlap to 15 mm so alignment stays easy.
Tape on the front or the back?
Back. Use ordinary clear tape on the reverse side across each joint. On the front, run a glue stick under the overlapping flap only if the poster will be handled a lot; most wall posters need nothing on the front.
Does the calculator account for scaling?
The grid assumes the poster prints at 100% scale (actual size). If you let the print dialog "fit" pages, the maths breaks and the assembled poster will be smaller than the target — always print tiles at 100%.