Compute your complaint rate per 1,000 delivered emails and see where it sits against the common provider threshold.
Complaints — Value for complaints. Provide accurate numbers for a reliable Complaints per 1,000. Example: 3.
Emails Delivered — Value for emails delivered. Provide accurate numbers for a reliable Complaints per 1,000. Example: 10000.
Complaints per 1,000
0.30 /1k
Complaints per 1,000 — Calculated outcome /1k. Derived from your inputs via the displayed formula; use to plan.
Complaint Rate
0.03%
Complaint Rate — Percentage %. Above 0 increases with input; compare to benchmarks or goals.
Threshold Status
Good — below the common 0.1% provider threshold
Threshold Status — Calculated outcome. Derived from your inputs via the displayed formula; use to plan.
What this means
Divide the number of spam complaints by the number of emails that were actually delivered, then multiply by 1,000 to express the result per thousand. This normalizes campaigns of different sizes onto the scale ISPs discuss: under 1 per 1,000 is good, 1–3 per 1,000 is close to the limit, and more than 3 per 1,000 is ...
Your spam complaint rate is the share of delivered emails that recipients mark as spam. Industry guidance expects you to stay well under the 0.1% (1 per 1,000) threshold that mailbox providers commonly use to protect both deliverability and domain reputation.
Formula
Rate = (complaints ÷ delivered) × 1,000
Worked examples
FAQ
What is a good spam complaint rate?
Staying under 0.1% (1 per 1,000 delivered) is the common expectation. Rates above that start to hurt sender reputation and inbox placement.
Why use complaints per 1,000 instead of a percentage?
Per-mille is how ISP feedback loops and deliverability guides usually quote thresholds, so it is easier to compare your number directly against the 0.1% guidance.