Common questions
Everything you need to know about Block Poster
Block Poster supports JPG, PNG, and WebP image formats. For best results, use a high-resolution image.
No! Unlike other tools that limit you to 2.5MB or 5MB, Block Poster has no file size limit. Everything is processed locally in your browser.
No. Your images never leave your device. All processing happens 100% in your browser using the Canvas API. We never see, store, or have access to your images.
We support A4, US Letter, A3, US Legal, and Tabloid paper sizes. You can also choose between portrait and landscape orientation.
Print all pages, trim the white margins if needed, then lay them face-down on a flat surface in order. Use masking tape to join the pages together from the back. The overlap setting helps with alignment.
Create single-image posters for free, without an account or watermark. Your images stay in your browser.
For best results, use an image that is at least 1000 pixels wide. Larger images produce better quality posters. You can also adjust the DPI setting — 150 DPI is a good balance between quality and file size.
Yes! Block Poster works on any device with a modern web browser. The interface is fully responsive and works on phones, tablets, and desktops.
The usual cause is scaling in the print dialog. Print the PDF at Actual Size or 100% scale, and turn off Fit to Page, Shrink oversized pages, borderless auto scaling, and any driver setting that changes page size. Print one test tile first.
For most home printers, 10-15 mm is practical. Use 5 mm only with a precise trimmer and stable paper feed. Use 15-20 mm for large posters, glossy paper, or printers that pull sheets unevenly.
No. Trim only the edges that will sit on top of another sheet, usually the right and bottom edges. Leave the opposite edges as backing tabs so the overlap has something to attach to.
A large poster needs more pixels than a normal photo print. Aim for about 150 pixels per printed inch for wall viewing and 300 pixels per inch for close viewing.
Yes. Choose the same paper size in Block Poster that is loaded in your printer. A4 and US Letter are close but not identical, so mixing them can shift the final dimensions.
Scale is the critical setting. Use Actual Size, 100% scale, or no scaling depending on your printer dialog. Do not use Fit to Page.
Most home printers cannot print to the physical edge of the paper. Block Poster accounts for margins and overlap so the printable areas still align.
Yes. Matte photo paper is easier to align and hides small seams better than glossy paper. Heavy paper can shift more during feeding, so print a test page first.
No. The PDF is generated in your browser with client-side code. Your image file is not uploaded to our server. Analytics and advertising scripts do not receive your uploaded image file.
Use standard 150 DPI output, reduce the number of pages, or start from a compressed JPG instead of a very large PNG.
Yes. Download the PDF and keep it like any other document. When you print later, use the same paper size and 100% scale.
Only use images you own, created yourself, or have permission to print. You are responsible for image rights and how the printed poster is used.