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About this tool
Quickly view and inspect your PDF files directly in your browser without Adobe.
PDF Previewer renders every page of a PDF as a contact sheet of thumbnails in the browser and re-renders any page you click at 2x scale in a full-size viewer. It uses the PDF.js rendering engine on a canvas, so you can read a document without installing Acrobat or handing the file to an online viewer. Nothing is saved or converted — it is a look-only inspector.
Open PDF Previewer on AltFTool — it loads instantly in your browser.
Click Choose PDF File in the "Drop your PDF here" panel; the picker accepts application/pdf. While it works the page shows "Processing your PDF..." and renders every page to a canvas at 0.25 scale.
The pages arrive as a thumbnail grid, each captioned Page 1, Page 2 and so on, with the filename and the page count in a bar above them. Upload New swaps in a different document without reloading the page.
Click any thumbnail to re-render that page at 2x scale in a dialog headed "Page N - HD Preview", which shows "Loading HD preview..." until the canvas is ready. There is no save or export — the tool only displays what is already in the file.
All pages render as thumbnails in one scrolling grid, so finding the page you want is a scan, not a page-by-page hunt.
Thumbnails render small for speed and any page you open re-renders at 2x scale, so detail is there when you need it and not before.
Thumbnails sit in an ISO A-series-friendly 1:1.414 box, so A4 and other A-series pages show their true shape; other page sizes such as US Letter are fit inside with their own proportions preserved, never stretched to fill the box.
No. This viewer renders pages with the PDF.js engine directly on an HTML canvas in your browser, so any modern browser can display the document with no reader installed.
No. It is a read-only inspector: it renders pages for viewing and does not modify, convert or re-save your file. Use a merge, split or reorder tool if you need to change the document.
Thumbnails are rendered at 25% scale so a long document loads quickly. Click any thumbnail and the page is re-rendered at 2x scale for a sharp full-size view.
No. The file is read as an array buffer in the page and every page is rasterised locally on a canvas. The PDF never leaves your device.