How to Make a PDF Smaller

The fastest way to make a PDF smaller is to use an online compressor. Browser-based tools like the Compress PDF tool on this site run entirely on your device — your PDF never leaves your browser, which is a major privacy advantage over server-based tools.

Choose from three quality levels: Light (20–40% reduction, minimal quality loss), Recommended (60–80% reduction, no visible quality loss for screen viewing), or Strong (85–95% reduction, some image softening). For email attachments, Recommended is usually the right choice.

This method works best for PDFs that contain scanned images or photographs. Text-heavy PDFs see only modest reduction because there's little image data to compress.

If you created the PDF from Word, PowerPoint, InDesign, or another authoring tool, re-export with the 'Minimum size' option selected. Most export dialogs include this option, and it applies compression at the source — which often produces better results than compressing an already-exported PDF.

In Microsoft Word: File → Save As → PDF → Options → 'Minimum size (publishing online)'. In Google Docs: File → Download → PDF Document (Google's default export is already well-optimized).

Re-exporting also strips out unnecessary content like hidden layers, comments, and unused embedded fonts, which can bloat the file without being visible. Starting fresh from the source application often produces a significantly smaller PDF.

If your PDF includes photographs or scanned pages, the source images are usually the largest contributor to file size. Resize and compress these images before inserting them into the source document, and you'll see dramatic reductions in the final PDF.

Aim for 150 DPI for screen viewing and 300 DPI for print. A 4000 × 3000 photo from a modern phone is overkill for a PDF that will be read on a laptop screen — resize it to 1920 × 1440 or smaller first. Save as JPG at 80% quality for photos, or PNG for screenshots with text.

Free image editors like GIMP, Photopea (browser-based), and the built-in Preview app on macOS all support batch resizing and compression. Spend two minutes on this step and your final PDF can shrink by 80% or more.

PDFs can embed the full font files used in the document, which ensures the document looks identical on every device but adds significant file size. A single font can add 100–500 KB, and a document using five fonts can easily gain 1–2 MB just from font data.

Font subsetting embeds only the specific character glyphs used in the document. If your document uses the word 'Hello' in a particular font, only the letters H, e, l, and o are embedded — typically a few kilobytes instead of hundreds.

In Adobe Acrobat: 'Save as Other → Reduced Size PDF' and ensure 'Embed only the fonts used' is selected. In LibreOffice: PDF export dialog → General tab → 'Embed fonts' (with subsetting).

PDFs can accumulate unnecessary content: hidden layers, comments, annotations, attached files, bookmarks pointing nowhere. This content bloats the file without adding visible value.

In Adobe Acrobat: File → Save as Other → Reduced Size PDF. This strips unnecessary content and applies basic compression. In Preview (macOS): File → Export → Quartz Filter → 'Reduce File Size'.

Be careful with this method for documents where annotations or comments matter (collaborative review documents, signed contracts with annotation history). Always keep a backup of the original PDF before stripping content.

If a single PDF is genuinely large because it contains a lot of content (a 200-page report, a multi-chapter thesis), compression can only do so much. Splitting the PDF into logical chunks — one per chapter or section — is often the most practical approach.

Use the Split PDF tool to extract page ranges into separate files. A 50 MB report split into five 10 MB chapters is much easier to email, upload, and review than a single 50 MB file.

Splitting also helps with accessibility: readers can download only the chapter they need, instead of pulling down a massive file just to read the first few pages.

PDF/A is an archival variant of PDF that embeds all fonts and restricts features that might not be supported in future PDF readers. It's required by some government and legal organizations for records retention.

PDF/A usually produces slightly larger files than standard PDF because of the strict font embedding requirements. Don't use PDF/A for size reduction — use it only when archival is the goal.

Most everyday PDF use cases (contracts, reports, manuals) don't need PDF/A. Standard PDF is smaller, more compatible, and sufficient for typical document workflows.

For frequent PDF optimization, dedicated software like Adobe Acrobat Pro, Foxit PhantomPDF, or PDFsam Enhanced offers more control than browser-based tools. These let you selectively compress images, remove specific objects, and fine-tune font embedding.

Free alternatives include PDFtk (command-line), Ghostscript (command-line, very powerful), and PDFsam Basic (graphical, focuses on splitting and merging but includes some optimization).

For most users, the browser-based Compress PDF tool on this site is enough. Reserve the heavy-duty tools for cases where you need fine-grained control or are processing many PDFs in batch.