The bandwidth stat on the Analytics page shows how much email data has passed through your account during the current month — the combined size of all emails forwarded.
Where to see it
It's shown in the summary bar at the top of the analytics page. There's also a Monthly Bandwidth Usage card in the Overview tab with a progress bar showing usage against your plan's monthly limit.
What counts toward bandwidth
Every email forwarded through your aliases counts — the message body, headers, and any attachments. Blocked emails (that didn't forward) don't count.
Emails with large attachments will eat through bandwidth much faster than plain-text messages.
Plan limits
Bandwidth limits depend on your plan. The progress bar shows how much of the current month's allowance you've used. The counter resets at the start of each calendar month.
If you're approaching your limit, consider whether any aliases are forwarding high-attachment emails that you don't actually need. You can deactivate those aliases or upgrade your plan.
What happens if you hit the limit
Forwarding continues but you'll see a warning. Check your plan details on the Billing page for the exact behaviour at the limit.