ClearBounce verified 807,203 email addresses in the first half of 2026. Our distribution analysis covers 229,305 addresses across 377 real mailing lists with full verification breakdowns. The verdict: the average list is far dirtier than marketers think.
The headline number
Across every list we analyzed, nearly 1 in 4 addresses was invalid, risky, or undeliverable — silently dragging down sender reputation and inbox placement before a single campaign is sent.
1 in 4
emails is invalid, risky or undeliverable
80%
of lists are at least 20% unusable
15.9%
invalid addresses in the median list
8.1%
sit on risky catch-all domains
Status breakdown of the 229,305 analyzed addresses (H1 2026 sample).
A further 8.1% of addresses live on catch-all domains that accept every message at SMTP time but may silently discard it — a hidden risk most free checkers mark as valid.
Of every address flagged undeliverable, here is the reason it bounced.
15.9%
invalid in the median list
45%
invalid in the worst 10% of lists
80%
of lists are ≥20% unusable
Mailbox providers typically start throttling or blocking senders once hard-bounce rates exceed 2–3%. At a median of 15.9% invalid addresses, most unverified lists are multiples over that threshold on their very first send.
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ClearBounce verified 807,203 email addresses in the first half of 2026 (1 January – 30 June) across bulk uploads, single checks and API calls. Distribution benchmarks on this page are computed from the 229,305 addresses across 377 completed bulk-verification jobs for which full per-status breakdowns were retained; API and single verifications are counted in the total volume but excluded from distribution metrics. Each address was checked through the full ClearBounce pipeline: syntax validation, domain & MX resolution, disposable and role-account detection, catch-all probing, and live SMTP mailbox verification from a distributed pool of sending IPs.
“Deliverable” means the mailbox accepted mail at SMTP time. “Invalid” means a hard rejection (no such user, dead domain, or syntax error). “Risky” covers catch-all, role, and low-reputation addresses that may accept but are unsafe to send to. “Unknown” means the receiving server could not give a definitive answer within the retry window.
Figures reflect real customer mailing lists and are not weighted by industry. Per-list statistics use the 364 analyzed lists with at least 10 addresses. Percentages are rounded to one decimal place.
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