Skip to content
M365Ops Toolkit
← All tools

Mailbox Usage Analyzer

Exchange Online

Free
Available

Summarize mailbox sizes, find the largest mailboxes and compare usage against thresholds.

Sign up free to use it

Upload a mailbox usage CSV, map the size and quota columns and set your warning threshold. Quota percentages are only calculated when valid quota data exists.

Supported input

Mailbox usage exports from the Microsoft 365 admin center or the Mailbox Usage Report script. Sizes in bytes, KB, MB or GB are detected; you can override the unit.