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Email verification statistics 2026: list decay, bounce rates and sender rules

Email verification statistics from 2025 and 2026 point the same way: a list you do not re-check gets worse every month. ZeroBounce found that at least 23% of the 11 billion+ addresses it checked in 2025 were invalid or risky, and cold email sent through Hunter bounced 3.6% of the time on average.

This page collects the list decay, bounce, inbox placement and sender-rule numbers we could check on each publisher’s own page, plus how Scalelist labels a verification result. Our own verification test is not published yet; the note below says what we will add.

What do email verification statistics tell you?

Email verification statistics tell you how much of a list will fail if you send without checking it, and how strict mailbox providers are about what happens next. The published numbers put decay at roughly a quarter of addresses a year and the average cold email bounce rate above 3%.

The sender rules turn those numbers into risk. Gmail, Yahoo and Microsoft publish requirements on authentication, spam complaints and unsubscribes, and Microsoft lists bounce management among the practices it recommends to high-volume senders.

Email verification statistics at a glance: 23% of checked addresses invalid or risky, 3.6% average cold email bounce rate, 1 in 6 emails miss the inbox, 0.10% spam line.
An unverified list loses about a quarter of its addresses in a year, and mailbox providers now set hard lines on spam complaints.

How we chose these email verification statistics

Every number on this page was read on the publisher’s own page, report or PDF. Last reviewed: 28 September 2026.

How fast email addresses go bad

Roughly a quarter of an unverified email list fails within a year, and people changing jobs is a large part of why B2B addresses stop working.

Statistic Source, year Sample
At least 23% of addresses submitted in 2025 were invalid or risky, down from 28% in 2024 ZeroBounce, 2026 11 billion+ addresses verified in 2025
Only 62% of addresses submitted in 2025 were valid; more than 9% were catch-all ZeroBounce, 2026 Same dataset
20.6% of US workers had been with their employer a year or less BLS Employee Tenure, January 2026 About 60,000 households
Median tenure is 3.3 years in sales jobs, 4.1 years overall and 6.1 years in management BLS, January 2026 Same survey
About 700,000 US business locations closed in 2023, about 9% of all employer establishments US Census Bureau, 2025 All US employer businesses
76% of CRM users said less than half of their CRM data is accurate and complete Validity, 2025 602 CRM users and admins in the US, UK and Australia

ZeroBounce’s figure is a share of what its customers chose to check, which likely skews toward older lists, and it mixes consumer and business addresses. ZeroBounce itself calls it a low-end estimate, because catch-all addresses cannot be confirmed either way.

Bar chart of median employee tenure by occupation (BLS, 2026): sales 3.3 years, all workers 4.1, business and financial 4.6, computer 4.6, management 6.1.
Lists of salespeople go stale faster than lists of managers, because their median tenure is about half as long.

Work emails are tied to the job. Validity’s 2024 survey of 631 CRM admins links data decay to layoffs and resignations for that reason, and 48% of those admins said customer data was decaying faster than a year earlier (Validity). How to measure decay on your own records: our B2B contact data decay study.

Email bounce rate statistics

The average cold email bounce rate published from a large sample is 3.6%, above the 2% ceiling that sending vendors advise.

Bounce types, the codes behind them and what to do with each: hard bounce vs soft bounce. If yours runs high: email bounce rate benchmarks and fixes.

Email deliverability statistics: inbox placement

One in six legitimate marketing emails missed the inbox in 2024, and Microsoft was the hardest major mailbox provider to reach.

Validity’s 2025 Email Deliverability Benchmark measured a global inbox placement rate of 83.5% in 2024: 6.7% of mail went to spam and 9.8% went missing. Spam placement nearly doubled during the year, from 4.5% in the first quarter to 8.6% in the fourth (Validity).

Bar chart of 2024 inbox placement by mailbox provider (Validity): Gmail 87.2%, Yahoo and AOL 86.0%, all providers 83.5%, Microsoft 75.6%.
Even permission-based email misses the inbox one time in six; Microsoft is the hardest of the big three.

These are seed-list tests of opt-in marketing email run by Validity customers. Cold email was not measured, so do not read 83.5% as a cold email benchmark.

Gmail, Yahoo and Microsoft sender rules in numbers

Gmail and Microsoft draw the bulk-sender line at 5,000 emails a day, Yahoo publishes no volume threshold, and all three require authentication.

Table of email sender rules: Gmail and Microsoft set a 5,000-a-day bulk line, Yahoo publishes none; all require SPF, DKIM and DMARC; Gmail spam rate under 0.10%.
The three providers agree on authentication; they differ on who counts as bulk and what happens when you fail.

Catch-all emails: the Risky share

More than 9% of the addresses ZeroBounce checked in 2025 were catch-all: the domain accepts mail for any address, so no verifier can confirm that a specific mailbox exists.

Scalelist labels these results Risky. By Scalelist’s own estimate, published in its help center, about 20% to 30% of Risky emails are actually deliverable, which is why we suggest sending them from a secondary domain rather than your main one (Scalelist help center). No method or sample is published for that estimate.

How catch-all domains work and how to send to them safely: catch-all emails explained.

How Scalelist labels a verification result

Scalelist returns every email it finds with one of three statuses, Valid, Risky or Not found, and charges only when an address is found.

Table of Scalelist email verification statuses: Valid (mailbox verified, 1 credit), Risky (catch-all, 1 credit, send from a secondary domain), Not found (0 credits).
Every email comes back with one of three labels, and you only pay when an address is found.

Behind each status sit seven checks: syntax, domain, MX records, the SMTP response of the mail server, catch-all detection, disposable-inbox detection and known spam traps. Verification is included with every email Scalelist finds, and you can run a list you already have through the Email Verifier.

Checklist of the 7 checks behind an email verification result: syntax, domain, MX records, SMTP, catch-all, disposable inbox and spam traps.
A catch-all domain accepts every address, so the mailbox itself cannot be confirmed: that result comes back Risky.

To run the same checks by hand, see how to verify an email address without sending. For what to do with each result, read what each verification status means.

What these email verification statistics mean for your list

If a quarter of a list can fail within a year and the average cold email bounces 3.6% of the time, verify right before each send, not once when the list was built.

For the list side of deliverability, read email deliverability starts with your list.

Find verified work emails for your next list: 1 credit per email found, nothing for a miss.

Get 20 credits to test it

How to cite this page

Cite this page as: Scalelist, “Email verification statistics 2026”, scalelist.com/research/email-verification-benchmark/, last reviewed 28 September 2026. When you quote a single number, also name its original publisher and year.

Related research: cold calling statistics with sources, our 2026 contact data benchmark of 8 providers and sales prospecting statistics.

FAQ

Where do these email verification statistics come from?

From each publisher’s own page or report: ZeroBounce, Hunter, Instantly and Validity for list, bounce and inbox data; Google, Yahoo and Microsoft for sender rules; the US Bureau of Labor Statistics and Census Bureau for tenure and business closures. Most vendor numbers describe their own customers’ data, so each carries its year and sample. Last reviewed 28 September 2026.

What percentage of email addresses go bad each year?

About a quarter, on the best current data. ZeroBounce found at least 23% of the 11 billion+ addresses it verified in 2025 were invalid or risky, down from 28% in 2024. That is a share of lists customers chose to check, not one list tracked for a year, so treat it as a direction rather than a precise decay rate.

What is a normal bounce rate for cold email?

The measured average is 3.6%: that is how often cold email sent through Hunter bounced in 2025, across 31 million emails. Sending vendors advise staying lower; Instantly’s 2026 benchmark report recommends keeping bounces under 2%. Verifying every address right before the send is the most direct way to get there.

How many email addresses are catch-all?

More than 9% of the addresses ZeroBounce checked in 2025 were catch-all, meaning the domain accepts mail for any address, so no verifier can confirm the mailbox. Scalelist labels these Risky. By Scalelist’s own help-center estimate, about 20% to 30% of Risky emails are deliverable, and they are best sent from a secondary domain.

Do Gmail’s bulk sender rules apply to B2B cold email?

Not directly. Google says its sender guidelines apply to mail sent to personal Gmail accounts, not to Google Workspace accounts, which host many company domains. For Gmail addresses, the rules start at 5,000 messages a day counted per primary domain, and require SPF, DKIM, DMARC, one-click unsubscribe and a spam rate below 0.10%.

Does Scalelist publish its own email verification benchmark?

Not yet. This page was planned around the share of Valid, Risky and Not found results by industry across Scalelist lookups, and that test has not been published. Until it is, the page lists third-party statistics and Scalelist’s status definitions only. Our published benchmark today covers email and phone found rates for 8 providers in 4 regions.

Sources