See the samplesStart comparing

NewSave any document as a PDF

See every change,
word by word.

PowerLens lines up two versions of a document side by side, marks every edit down to the word, and lets you copy the changes you want from one version to the other. It all happens in your browser.

Drop your first document here

Choose one, then the version to compare it with — or both at once.

Word, Google Docs, PDF, OpenDocument, RTF, EPUB, HTML, Markdown, CSV or text

No file to hand? Try a sample document, image or recording

  • No account
  • Nothing uploaded
  • Word, PDF, Google Docs and more

Reads the files you already have

  • Word.docx .doc
  • Google Docs
  • PDF.pdf
  • OpenDocument.odt
  • Rich Text.rtf
  • EPUB.epub
  • Web pages.html
  • Markdown.md
  • CSV.csv .tsv
  • Text and code.txt .json …

What it does

Everything you need to reconcile two drafts

For contracts, papers, briefs and manuscripts: anything that comes back with changes.

  • Every change, marked

    Paragraphs line up side by side. Words only in A are marked in red, words only in B in green, and formatting changes are flagged on their own.

  • Copy changes across

    Take a single word, a paragraph, a table row or everything at once, in either direction. Every copy can be undone.

  • Formatting stays put

    Word and OpenDocument files keep their styles, headers, footers and page setup. Only the paragraphs you copy change.

  • Save it your way

    Export the result as Word, PDF, OpenDocument, RTF, a web page, Markdown or plain text, or copy it formatted into Google Docs.

  • Private by design

    Documents are read and written inside your browser tab. Nothing is uploaded unless you choose to keep a comparison on the server, or to transcribe recordings there, and there is no account to create.

  • Quick from the keyboard

    Jump between changes with N and P, copy the current one with Alt and an arrow key, and undo with Ctrl+Z.

How it works

Two drafts in, one clean copy out

  1. 01

    Drop the first version

    Drag a document onto this page, or choose one from your computer.

  2. 02

    Add the other version

    Pick the draft to compare it with. PowerLens lines the two up and marks every change.

  3. 03

    Keep what you want

    Copy edits across with a click, then save the merged document in its own format.

Start a comparison

Round trip

At home with Google Docs and Word

Download a Google Doc as Word or paste it straight in: headings, lists, tables, bold, italic and links come along. When you are done, upload the merged file to Drive, or paste the formatted text back over the original.

  • Word and OpenDocument files keep their own styles, headers, footers and page setup
  • Tracked changes are compared as if accepted, and kept as they are when you export
  • PDFs, EPUBs and old .doc files can be compared and copied from, then saved in another format

Your documents stay in your browser

PowerLens reads, compares and saves files inside the tab you are using. Nothing goes to a server unless you choose to keep a comparison or transcribe recordings there, and there is no account to create, so private drafts stay private.

Ready when your next draft is.

Choose the first version and PowerLens will ask for the other. You will see every change in seconds.

or try one of the samples first