Hotmail is a Freemail (Microsoft). Across 253,445 Hotmail addresses verified by BounceZero between April and October 2026, 16.5% were invalid, 0.1% catch-all, 0.0% unknown and 70.5% confirmed valid. The verdicts are reliable and can be acted on directly.
Every Hotmail address BounceZero verified for customers between April and October 2026, beside the corpus benchmarks. The remainder of each row to 100% is risky and role results.
| Segment | Addresses | Invalid | Catch-all | Unknown | Confirmed valid |
|---|---|---|---|---|---|
| Hotmail | 253,445 | 16.5% | 0.1% | 0.0% | 70.5% |
| All non-freemail domains (business and ISP) | 6,514,884 | 14.5% | 2.3% | 27.0% | 32.6% |
| Business domains only (consumer ISP and freemail excluded) | 1,269,919 | 22.9% | 9.4% | 22.5% | 40.3% |
| All freemail | 1,415,154 | 17.6% | 1.1% | 2.1% | 74.0% |
Non-freemail includes consumer ISP mailboxes; a business-only cut is on the benchmarks page. Method and every other cut: Lead List Quality Benchmarks 2026. Risky and role on the Hotmail row: 12.9%.
Microsoft answers probes for the consumer Outlook platform clearly, so unknowns and catch-alls are near zero. The invalid share is higher than Gmail because Hotmail accounts are older on average and Microsoft recycles dormant addresses, so a list that was clean two years ago has lost mailboxes since.
Hotmail is the oldest large freemail brand and now runs on Outlook.com. It remains common on B2B lists built from forms and trade registrations in Europe, Latin America and Asia, where small business owners used the free account for years. Microsoft's consumer platform publishes sender requirements close to Google's, with authentication and a complaint threshold, and it is quick to junk-folder new domains, so Hotmail-heavy segments should be sent from a warmed domain at low daily volume.
On confirmed-invalid rate, Hotmail ranks 14 of 29 providers in the corpus, just behind AOL at 17.9%, ahead of T-Online at 13.9%.
On unknown rate, Hotmail ranks 27 of 29 providers in the corpus, just behind Windstream at 0.1%, ahead of Gmail at 0.0%.
On confirmed-valid share, Hotmail ranks 3 of 29 providers in the corpus, just behind iPrimus at 93.9%, ahead of Alice (TIM) at 64.7%.
How to read these rates: they are BounceZero's probe outcomes on customer lists over April to October 2026, not a census of Hotmail mailboxes. Unknown and catch-all measure what verification could not confirm, which depends on the provider's gateway policy during the window as much as on the addresses. The lists are the ones customers chose to upload, so segments dominated by a few large uploads carry their age and source. Method and limitations: benchmarks page.
Hotmail rarely returns unknown. When it does, re-check once; a second unknown usually means a dormant mailbox.
Roughly one in 6 Hotmail addresses is dead, against about one in 7 across non-freemail lists.
Catch-all is negligible on Hotmail (0.1%); when this provider does return valid, the mailbox accepted the probe itself rather than a blanket accept.
With 70.5% of addresses confirmed live, Hotmail is a segment you can send to from the main domain without a second thought beyond re-verifying before every send.
Trust the verdicts. Re-verify Hotmail-heavy segments quarterly; the invalid share grows faster than on Gmail. Hotmail recipients also sit behind Microsoft's complaint filtering, so keep the send relevant.
Role addresses such as info@ and sales@ make up 0.0% of Hotmail addresses in the corpus. Role addresses are rare here, as expected for a mailbox provider.
16.5% of 253,445 Hotmail addresses verified by BounceZero between April and October 2026 were confirmed invalid, against 14.5% across non-freemail domains and 17.6% across freemail.
0.0%. Unknown means the mailbox could not be confirmed either way, usually because the gateway deferred the probe. BounceZero refunds unknown results; on Hotmail it is rare enough to re-check once and move on.
Not in practice: 0.1% of Hotmail addresses returned catch-all, so a valid verdict means the mailbox exists.
70.5% confirmed valid at verification time. Keep bounces under 2% and complaints under 0.3% on the send, and re-verify the segment before every send.
Upload the file and see valid, invalid, catch-all and unknown per row, with the Hotmail segment against this benchmark. 100 free checks a month, unknowns refunded.
Ayoub built BounceZero's 5-stage validation pipeline, its dedicated BGP-announced IP infrastructure, and the Patroni HA PostgreSQL cluster behind every verification. Previously built high-volume email delivery infrastructure. Trained at 1337 Benguerir (École 42 network, 2019). Open-source: bgp_analyzer.
Invalid, catch-all and unknown rates per email provider and country domain, 2026
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