How to search for text inside a PDF

The fastest way to find a word inside a single open PDF is to press Ctrl+F (or Cmd+F on a Mac). The harder problems — searching dozens of PDFs at once, dealing with scanned pages, and matching patterns rather than exact words — need a different approach. This guide walks through all of them, and you can try most of them immediately with our in-browser PDF text search tool.

Searching inside one PDF

Every mainstream PDF reader has a find box. In Chrome, Edge, Firefox or Safari, open the PDF and press Ctrl+F or Cmd+F; a small search field appears and steps through each occurrence as you press Enter. Adobe Acrobat Reader offers the same with a richer panel (Edit › Find, or Ctrl+F) and an Advanced Search (Shift+Ctrl+F) that lists every hit with context in a side panel. For a document you already have open, this is all you need.

The catch is that the find box only ever searches the one file in front of you. The moment you have a folder full of documents and you do not know which one contains the phrase, opening them one at a time becomes painful.

Searching across many PDFs at once

This is the request we hear most often, and it is exactly what built-in find boxes cannot do. There are three common solutions:

• Your operating system's search index. Windows Search and macOS Spotlight can index the text of PDFs and find files that contain a word. They are good at telling you which file matches, but they do not show you the page number or the surrounding sentence, and indexing scanned documents requires extra setup.
• A desktop PDF app. Acrobat Pro's “Search in multiple files” and tools like DocFetcher can search a folder and return per-file results. They are powerful but either cost money or take time to install and configure.
• A browser tool that reads the files locally. The tool on this site lets you drop a whole set of PDFs in, search once, and see every match grouped by file with its page number — without installing anything and without uploading your documents. For occasional searches across a handful of files, this is usually the quickest path.

Whichever route you pick, the principle is the same: the tool extracts the text layer of each document and matches your query against it. The differences are about convenience, privacy and how the results are presented.

Why a search sometimes finds nothing

If you can see the words on the page but no search will find them, the PDF almost certainly contains images of text rather than text. This happens with anything produced by a scanner or a photograph of a document. To the computer, the page is just a picture, so there are no characters to match. The quickest test is to try to select the text with your mouse: if you cannot highlight it, no search tool can find it.

The fix is optical character recognition (OCR), which analyses the image and writes a hidden text layer behind it. Acrobat Pro, many scanner apps, and free tools can add OCR. Once a document has been OCR'd, it behaves like any other searchable PDF. Our tool reads whatever text layer exists; it does not perform OCR itself, so a pure scan will return no matches until you have processed it.

Matching patterns with regular expressions

Sometimes you are not looking for a fixed word but for a shape of text: an invoice number, a date, an email address, a reference code. A regular expression (regex) describes that shape. A few that come up constantly:

• \b\d{4}\b — any standalone four-digit number, such as a year.
• invoice[-\s]?\d+ — the word invoice followed by a number, with or without a dash or space between them.
• [\w.+-]+@[\w-]+\.[\w.-]+ — an email address.

In the tool, tick the Regex box and type the pattern into the search field. Leave it unticked and your text is treated literally, which is what you want for an ordinary phrase. The Whole word and Match case options cover the most common needs without writing a pattern at all.

Getting cleaner results

PDFs store text in fragments, and the spacing between those fragments is often approximate. As a result, a search for a long exact phrase can fail because an invisible line break sits in the middle of it. If you are sure a phrase is present but cannot find it, search for the most distinctive single word instead, then read the surrounding snippet to confirm. Our tool normalises runs of whitespace before searching, which removes most — though not all — of these surprises.

Putting it together

For one open document, press Ctrl+F and move on. For a folder of files, use a tool that searches them together and reports the page numbers, like the one on the home page. If nothing matches text you can see, suspect a scan and run OCR. And when you need to match a pattern rather than a word, reach for a regular expression. To decide which kind of tool fits your situation, see our comparison of browser, desktop and online PDF search.