What is the safe threshold for hard bounces?

Hard bounce thresholds guide list quality standards:

Industry benchmarks:

Excellent: Below 0.5%. Good: 0.5-1%. Acceptable: 1-2%. Concerning: 2-5%. Critical: Above 5%.

ESP enforcement:

Most ESPs flag accounts above 2%. Account review typically triggered at 5%. Suspension common above 10%.

Context matters:

New list or source: Higher initial bounces expected. First send to dormant segment: May spike. Regular sends: Should be consistently low.

Calculation:

Hard bounces divided by messages sent. Exclude soft bounces from this metric. Track over time, not just single sends.

Keep hard bounces under 2% as your north star. Above that, list quality needs attention.