Compress a PDF to Send on WeChat
If a PDF stalls on WeChat, size may be the issue: a single file sent in chat is typically capped around 100MB on mobile, and a recipient on mobile data may not want a 40MB file. Compress PDF may reduce transfer time, data and storage use, but cannot guarantee a successful send. Compression is local, with nothing uploaded. Below: WeChat's send limits and how to compress.
What are WeChat's limits for sending a PDF?
WeChat caps the size of files sent in chat, and the exact limit varies a little by entry point and device. More than the hard cap, the common annoyance is 'it sends, but slowly' or a recipient who won't download a large file on mobile data.
- Sending a single file in chat: typically capped around 100MB on mobile; larger files won't send.
- File Transfer (phone ↔ computer): subject to the same size limit, and large files fail to transfer more often.
- Sending to a group: a big file takes up storage for everyone and is slower for the group to download — smaller is more considerate.
- Official Account / Mini Program back ends: often have much tighter caps (a few MB up to tens of MB) — compress to whatever the dashboard requires.
How do you shrink a PDF so it sends on WeChat?
Compressing on a computer and then sending via File Transfer to your phone or the recipient is the smoothest path, but a mobile browser opens compress cat just as well.
- Open Compress PDF and drag in the file you want to send.
- For a lighter transfer, try a target such as 5120 KiB or 10240 KiB, then check the displayed bytes against the receiving limit.
- Review the file's method, then click 'Compress files'. 'Keep selectable text' is the default; 'Compress as images' removes selectable text and may soften details. Check output bytes and all pages.
- Download, then send it via WeChat's 'send file'. Scans and photo PDFs compress best.
Will compression hurt the quality?
Scanned contracts, forms and documents may shrink when their images are compressed, but detail loss varies. Start with 'Keep selectable text' and inspect every page if you choose 'Compress as images'.
- Scans / photo PDFs: image compression may save space, but check small print and any existing OCR layer.
- Pure-text documents (PDFs exported from Word): start with 'Keep selectable text'; they may already be small enough.
- Good enough beats tiny: the recipient just needs to read it, so 10MB is often safer than 2MB.
- Zoom in to check text, stamps and signatures after compressing, then send.
Frequently asked questions
WeChat says my PDF is too large to send — what do I do?
Try a target whose bytes fit WeChat's limit (typically around 100MB on mobile), then inspect the actual output. For a lighter transfer, 5120 KiB or 10240 KiB are possible targets, but reaching the target or completing a send is not guaranteed. Processing is local, with nothing uploaded.
Can I compress a PDF on my phone before sending it on WeChat?
Yes. Open compress cat's Compress PDF in your phone browser, pick the file and a target, compress, download, then send it via WeChat's 'send file'. You can also compress on a computer and send it across with File Transfer.
An Official Account back end has a much tighter limit — can I hit a few MB?
You can request a target that fits the dashboard's limit (e.g. 2MB or 5MB), but the output may remain above it. Targets use KiB, so compare the displayed and output bytes with the dashboard's cap. Review the method and clarity before uploading.
Is it safe to process the file in compress cat?
Yes. Compression runs entirely in your browser via WebAssembly, so the PDF is never uploaded and stays on your own device.
Updated · compress cat team