Compress a PDF to an exact target size in KB or MB — or pick a quality preset. Everything runs in your browser, so your documents never leave your device.
1. Add your PDF files
Drag & drop PDFs here
or
2. Choose how much to compress
The tool runs several passes and keeps the highest quality version that fits your target.
Files are processed locally in your browser. Nothing is uploaded to a server.
Free file tool
Free PDF Size Reducer online
Re-encode PDF page content and images toward a smaller downloadable file while making clear that an exact target cannot be guaranteed for every document. Use the tool directly in your browser with no sign-up. It is designed for one source at a time so the workflow stays simple and easy to verify.
Free to use
No payment required for this tool.
One source at a time
Process and verify one source before the next.
Browser-based
The conversion workflow runs from the web page on your device.
No sign-up
Start the file workflow without creating an account.
What PDF Size Reducer is useful for
✓Meeting PDF upload-size limits
✓Reducing attachment size
✓Creating a smaller sharing copy of a large document
Input and output checks
Accepted input: pdf.
✓Open the downloaded output before deleting or replacing the source file.
✓Check the details that matter for your use: page count, dimensions, orientation, text, duration or metadata.
✓If quality or size matters, compare more than one settings combination before choosing the final copy.
How to use this calculator: PDF Size Reducer
1Upload the PDF and note its original byte size and page count.
2Choose a realistic target or quality level; text-heavy and image-heavy files compress differently.
3Run the reducer and compare original size with the actual downloaded size.
4Open the result and inspect small text, diagrams, scanned pages, links and page count before using it.
Worked conversion example
Example: upload a 12 MB source file, choose a moderate quality setting, and run the tool. Exact output size depends on image detail, fonts, pages, duration and codec efficiency; compare the downloaded result visually before replacing the original.
Accepted input
pdf
Batch behaviour
One source at a time
Output settings
Setting
Example/default
Effect
Target file size
Selected target
The engine attempts the target, but source complexity and minimum readable quality can prevent an exact size.
Image quality
Automatic
Lower values reduce image bytes but can introduce blur or compression artefacts.
How the browser process works
Re-encode PDF page content and images toward a smaller downloadable file while making clear that an exact target cannot be guaranteed for every document. The page sends the selected file and settings to its pdf-size-reduce browser engine, creates a new output and downloads it without overwriting the source.
Privacy, quality checks and limitations
Keep the original file until the downloaded output has been opened and checked.
Verify page count, orientation, dimensions, text legibility, audio/video duration and metadata relevant to your use.
Browser-local processing reduces routine upload exposure, but your device, browser extensions and download location still matter.
A converted preview is not proof of legal authenticity, archival compliance, accessibility or digital-signature validity.
How the PDF size reducer works
1Upload one or more PDF files.
2Choose a target size such as 100 KB, 200 KB or 1 MB, or select a quality preset.
3Run the PDF size reduction process.
4The tool tests quality and render-scale settings to approach the requested target.
5Review the result and download the smaller PDF.
Frequently asked questions
Upload the PDF, switch the mode to “Target file size”, type the size you need (for example 100 KB) and press Reduce PDF size. The tool automatically searches the best combination of render scale and JPEG quality until the output lands at or below your target.