Compress PDF

Make a PDF smaller for email, WhatsApp or a form that has a size limit. Light mode keeps the text exactly; strong mode is for scanned or photo-heavy PDFs. The file stays on your device.

FreeNo sign-upRuns in your browser: your data is not uploaded

Why some PDFs barely shrink

A PDF made from Word or a web page is mostly text and fonts, which are already compact. Light mode cleans it up (duplicate objects, old versions of edited pages, metadata) and saves it in the tightest layout, but there is not much to remove, so expect 5% to 30%.

A scanned document or a PDF full of photos is different: each page is a large image, often saved at 300 dpi or more. That is where Strong mode helps. It redraws every page at the resolution you pick and stores it as a JPEG. A 20 MB scan usually ends up around 1 to 2 MB at 100 dpi.

Which settings for which job

You need	Mode	Resolution
Email or WhatsApp attachment	Strong	100 dpi, 60% quality
Upload limit on a government or job portal (e.g. 1 MB)	Strong	72-100 dpi, lower quality until it fits
Contract or form that must stay searchable	Light	-
Print at the office	Strong	150-200 dpi, 75% quality
Black-and-white scans	Strong + grayscale	100-150 dpi

What you lose in Strong mode

The text becomes part of the picture: you cannot select, copy or search it, and screen readers cannot read it. Links and form fields are removed too. For an ID scan or a signed form that is fine; for a report someone will edit or search, use Light mode or send the original.

Privacy

Both modes run in your browser with open-source libraries (pdf-lib and Mozilla's pdf.js). Nothing is uploaded, which matters for passports, bank statements and contracts. To combine several files first, use the merge PDF tool.

FAQ

How do I compress a PDF to under 1 MB?

Choose Strong mode, 100 dpi and 60% quality, then check the size. If it is still too big, pick 72 dpi or lower the quality, or tick grayscale.

Will the PDF still be readable?

At 100 dpi text is clear on a screen; for printing choose 150 dpi or more. Open "Check" to see the result before sending.

Does Light mode change how the PDF looks?

No. It keeps every page, font and image as they are and only removes waste from the file structure.

Is my PDF uploaded?

No. The compression runs on your own device; you can even go offline after the page loads.

Related guides

Link to this tool

Found it useful? Put a link in your docs, README or forum answer so others can use it too:

HTML

<a href="https://headsntail.com/tools/compress-pdf">Compress PDF</a> (free, by HeadsNTail)

Markdown (GitHub, Stack Overflow, dev.to)

[Compress PDF](https://headsntail.com/tools/compress-pdf)

Need a website, HR or business system? HeadsNTail builds websites, HR and payroll apps and business tools. See services or ask a question.

More free tools

Free Resume Builder (PDF, no sign-up)Fill in a form, pick a template, download a real-text PDF. Draft stays in your browser, works in any language. QR Code GeneratorFree static QR codes for links, Wi-Fi, email, phone, SMS and contact cards. PNG and SVG, never expire. Image Compressor (JPG, PNG, WebP)Shrink and resize photos to a target size like 100 KB. Batch, in your browser, nothing uploaded. Merge PDFCombine PDF files into one, in the order you choose. No upload, no watermark, no page limit. SQL to Laravel Migration ConverterPaste CREATE TABLE, get a ready Laravel migration file with foreign keys, indexes and timestamps. PHP Unserialize Viewer & Serialized String FixerRead serialized PHP data as a tree, JSON or PHP array, and repair broken string lengths after a domain change.