Compress PDF
Reduce one PDF or a full batch for easier email sharing, web uploads, and compact archiving. Apply one honest compression setting to the queue, process files locally one at a time, and keep every successful result even if another PDF fails.
Your files never leave your device. All processing happens locally in your browser with no file uploads or account required.
How to compress PDF files in a batch
- 01
Select one or more PDFs
Choose several PDF documents at once or add more files to the queue while keeping their order.
- 02
Choose compression strength
Use a balanced, strong or maximum image-compression preset, or open Advanced settings for lossless rewriting and exact quality controls.
- 03
Download your results
Download one PDF directly, save a batch as a ZIP, or merge successful compressed PDFs in queue order.
Important details & limitations
Compress PDFs sequentially with balanced, strong or maximum presets. Advanced lossless mode preserves text and links; image modes flatten pages. Download batch results separately, as a ZIP, or merge them in queue order.
Compress PDF files online for free
PDFira reduces one PDF or many PDFs in a single browser session. Batch files are processed sequentially to limit memory use, and each completed result remains available if a later document cannot be processed. Download successful files individually, package multiple results in a ZIP, or merge them after compression.
File-size savings depend on each PDF's internal structure. Image-heavy and scanned documents often shrink substantially, while clean text and vector documents may already be compact. If a compression attempt would make a file larger, PDFira safely retains the original instead of claiming a reduction.
Why compress a PDF?
Easier to email
Meet email attachment limits without splitting your file.
Faster uploads
Upload documents quickly to web portals and forms.
Save storage space
Reduce a complete document batch with one set of controls.
Flexible batch downloads
Save individual PDFs, create a ZIP, or merge successful results.
Private batch PDF compression in your browser
PDFira performs compression, ZIP creation, and optional merging entirely on your device. Files are never uploaded to a PDFira processing server. Sequential processing avoids rendering several large documents at once, which makes the batch workflow more practical on laptops and mobile devices.
Frequently asked questions
Can I compress multiple PDFs at once?+
Yes. Add multiple PDFs to the queue, choose one compression setting, and PDFira processes them sequentially in the displayed order.
How do I download a compressed PDF batch?+
Each successful PDF has its own download button. When two or more files succeed, you can also download all results in a ZIP or merge them into one PDF.
Are my files uploaded during batch compression?+
No. PDF compression, ZIP creation, and merging all happen locally in your browser. Your files never leave your device.
Does compressing a PDF reduce text quality?+
Lossless mode preserves text, links, and vector quality. Recommended, Strong, and Maximum use image compression, which flattens pages and can reduce sharpness as compression increases.
What happens if compression makes a file larger?+
PDFira keeps the original file and clearly labels it as retained. It does not claim a size saving or replace the original with a larger result.
What happens if one PDF is damaged?+
That file is marked as failed while the rest of the queue continues. You can retry the failed file without losing completed results.
Can I compress scanned PDFs?+
Yes. Scanned PDFs are image-heavy, so the image-compression presets are often effective. Results depend on scan resolution and existing compression.
What does lossless compression do?+
Lossless mode rewrites PDF objects without changing visual quality or flattening text and links. Already optimized PDFs may not become smaller.