Spam complaint rate
Also called: complaint rate, spam rate
The share of delivered messages that recipients mark as spam, as reported to senders in Google Postmaster Tools. Google asks senders to stay below 0.10% and never to reach 0.30%.
In plain terms
How often people hit the spam button on your mail. Two numbers matter: the target and the ceiling.
Why it matters for deliverability
This is the metric with the sharpest published threshold in the whole of deliverability, and the one with the least warning. Crossing it affects everything you send to that provider, not just the campaign that caused it.
What to do about it
- Watch the rate per campaign and per segment, not just as a monthly average.
- Treat 0.10% as the working limit, not 0.30% — the higher figure is where damage is already happening.
- Make unsubscribing easier than complaining, which is the only durable fix.
Source
Google — Email sender guidelines
“Keep spam rates reported in Postmaster Tools below 0.10% and avoid ever reaching a spam rate of 0.30% or higher.”
Checked 2026-08-29
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Definitions reviewed 2026-08-29. Spotted something wrong? Tell us.
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