How to compress a PDF
- Choose Compress PDF free and use Attach PDF to open the document. Keep the source available because compression produces a separate, image-based copy.
- Select a Quality option: High compression, Balanced or Better quality. Choose a Scale option: Smallest file, Balanced or Sharper pages. Balanced settings are a useful first test.
- Choose Compress PDF and wait for the result. Review the size feedback rather than assuming that processing always reduces the file. Some PDFs are already efficiently encoded.
- Download and open the processed copy. Check small text, diagrams and scanned details. If the result is too blurry or larger than the original, adjust the settings or keep the source instead.
Documents worth trying
A scanned meeting pack, photographed receipt bundle or illustrated handout can contain large images that make sharing awkward. Reducing image detail may produce a more manageable screen-reading copy. An archive scan may need more detail than an informal email reference, so choose settings for the actual purpose.
Check the destination's attachment limit and measure the result against it. FlowPDF does not promise a particular percentage reduction or a file below a chosen number of megabytes.
Understand the image-based output
The compressor renders PDF pages as images and places those images into a new PDF while preserving page dimensions. This differs from a lossless optimizer that keeps every original text and document object. Searchable or selectable text, interactive fields and links are not retained as their original interactive content. A scan may already behave like an image, but a digital text document can lose useful features in this conversion.
When compression is not the right choice
A lightweight text-only PDF may become larger after rasterization. Lower settings can soften fine print, signatures, barcodes and line drawings. Do not use a compressed copy as your only archive when exact detail or original document features matter. This tool does not perform OCR, repair a broken PDF, or preserve a certificate-backed signature's validity. If the document is large because it contains unnecessary sections, removing or extracting pages may be more appropriate than reducing every page's detail.
Compression without a document upload
The PDF is processed in the browser, not uploaded to a FlowPDF server. You can use the controls and download the result without signup or payment. Processing larger files depends on your device's available memory. Website resources and limited analytics are described separately in the privacy policy; they are not a document-upload service.