Outlook says my PDF is too large — what size should I use?

Many orgs land around 10–20 MB or less. When a portal or form states 1–2 MB, use Target size.

Does this upload to Microsoft?

No. mypdf compresses in your browser; you attach the result in Outlook yourself.

Safe to email after compressing?

Size is only one risk — also run the privacy checker for hidden data.

Short answer

Outlook and Microsoft 365 often enforce smaller attachment caps than consumer Gmail. Compress locally below, then attach. Prefer Keep text when the recipient needs selectable text.

Stays on your device·No upload·No account·No watermark·Offline after install·How it works Methodology Privacy

Compress PDF for Outlook

Free · private · files stay on your device

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How it works

1
Open the PDF you want to shrink.
2
Choose Keep text (recommended), Max shrink, or Target size.
3
For target size, type a number and pick KB or MB; for max shrink, pick Low / Medium / High (or custom DPI).
4
Click Compress, check the resulting size, and download.

Files never leave your device

Your PDF is processed in this browser tab. Files never leave your device, and mypdf.space does not receive uploads. No account, no watermark, no server-side copy.

Limits worth knowing

Org policies vary — follow your IT limit when stated.
Password-protect after compress if the content is sensitive (Confidential Send).

Frequently asked questions

Outlook says my PDF is too large — what size should I use?
Many orgs land around 10–20 MB or less. When a portal or form states 1–2 MB, use Target size.
Does this upload to Microsoft?
No. mypdf compresses in your browser; you attach the result in Outlook yourself.
Safe to email after compressing?
Size is only one risk — also run the privacy checker for hidden data.

Written by Sumit · Last updated 23 Oct 2026