How to compress a PDF for an email attachment limit
Most email providers cap attachments at around 20–25 MB. Here's the fastest way to shrink a PDF until it fits — entirely in your browser, no upload.
Open the Compress PDF tool →If you’ve tried to email a scanned contract or a slide deck and gotten an “attachment too large” error, you’re hitting a hard limit your email provider sets — typically 20–25 MB. The fastest fix is to compress the PDF so it fits, and you can do it here in seconds in your browser, without uploading the file anywhere.
Why email size limits exist
Email was never designed to move large files. To keep mailboxes manageable and protect against abuse, providers cap individual messages:
- Gmail — 25 MB
- Outlook / Microsoft 365 — 20 MB
- Yahoo Mail — 25 MB
- iCloud Mail — 20 MB
Go over the cap and most providers either bounce the message or push you to upload to their cloud storage and share a link — which means handing them a copy of your file. Compressing locally avoids both.
How to shrink the file
The walkthrough is short: open the tool, drop the PDF in, choose a level, download. The “Recommended” preset is the safe default; it downsamples embedded images to roughly 150 DPI while leaving text and vectors alone, which usually halves (or better) a scan-heavy PDF without visible quality loss.
If the result is still too big:
- Try “High” — drops image resolution to about 72 DPI. Great for screen viewing and email; not for printing.
- Drop unneeded pages first. Run the file through the Delete Pages tool before compressing. Blank scanned pages and duplicate copies are easy wins.
- Split into smaller files. If a single PDF still won’t fit, the Split PDF tool breaks it into ranges you can email separately.
Tips for hitting a specific limit
- Check the actual size after compressing. The tool shows you the exact before and after — so you’ll know whether you’ve cleared the cap on the first try.
- Sender vs. recipient limits. Your provider’s cap is one thing; your recipient’s may be lower. If you’ve heard “the file was rejected,” shrink more aggressively.
- Email clients can re-encode attachments. Some webmail clients add a small overhead — leave yourself a megabyte or two of headroom.
When compression isn’t the answer
If the PDF you’re sending is genuinely huge — say, a 200 MB scan archive — even maximum compression probably won’t get you under 25 MB. In that case, either split it (Split PDF) and send in pieces, or use a privacy-respecting file-sharing service. But for the vast majority of “I just need to email this PDF” situations, compression alone clears the bar.
Step by step
- Open the Compress PDF tool.
- Drag your PDF onto the upload area (or click to choose it).
- Pick a compression level — start with “Recommended”.
- Click “Compress PDF” and check the before/after sizes.
- Download the compressed file and attach it to your email.
FAQs
- What's the maximum attachment size for common email providers?
- Gmail caps attachments at 25 MB, Outlook.com and Microsoft 365 at 20 MB, Yahoo Mail at 25 MB, and iCloud Mail at 20 MB. If your file is over the limit, the message bounces back or the provider auto-uploads it to their cloud storage and shares a link instead.
- Which compression level should I pick to email a PDF?
- Start with “Recommended” — it usually shrinks scanned or image-heavy PDFs by 50–80% while keeping text crisp. If the result is still over the limit, try “High” and check the result; for a print-quality file pick “Low”.
- What if compression doesn't shrink the file enough?
- For text-only PDFs there's little to compress. If a single PDF is still too large after High compression, split it into smaller files with the Split PDF tool and send them as separate messages.
- Is my file uploaded to compress it?
- No. The compression engine (Ghostscript compiled to WebAssembly) downloads to your browser once, then your PDF is shrunk locally on your device. You can verify it in your browser's Network tab — your file never leaves your computer.
Related guides
- Compress for passport / visa Government portals often cap PDF uploads at 1–2 MB. Here's how to compress a passport application PDF until it fits — privately, in your browser.
- Compress a scanned PDF Scanned PDFs are usually mostly image — and image PDFs shrink dramatically. Here's how to compress a scanned PDF in your browser without sacrificing legibility.
- Extract pages from a PDF Sometimes you only need a few pages from a long PDF — a single contract clause, two pages from a long report. Here's how to pull them out, in your browser.