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Drop in a CSV of leads. Each email’s domain is compared with the company’s website, and every row where they differ is flagged. That is the usual sign the person has moved on and the address belongs to an old employer.
Your file never leaves your browser. Nothing is uploaded. The check runs on this page, on your device. Watch your browser’s network panel while it runs, or go offline once the page has loaded: it still works.
Drop a CSV on the page, or choose a file: comma, semicolon or tab separated, up to 50 MB. Export from Excel or Google Sheets as CSV first. The checker picks the email column and the company website or domain column for you; change either if it guessed wrong. It then counts every row as a match, a mismatch, free-mail or missing data, lists the flagged rows, and lets you download them as a CSV with every original column plus the flag. No file handy? The page has a sample list to try.
Short answer: To find job changers in a lead list, compare each contact's email domain with their company's website domain. When the two differ, the address often belongs to a past employer. This checker runs that comparison on a whole CSV inside your browser. Treat each mismatch as a flag to check by hand, not as proof the person left.
I take two columns from your file, the email and the company website, and check every row:
https://www.Acme.com/about becomes acme.com.uk.acme.com matches acme.com.The mismatch rate is mismatches divided by matches plus mismatches. Free-mail and incomplete rows stay out of it.
On 8 October 2026 I audited two B2B client campaigns. In the first, 3,378 of 14,141 contacts (24%) had an email domain that did not match the company named in the email. Among the contacts already emailed, it was 441 of 1,822 (24%). The second campaign ran three lists: 490 of 2,688 (18%), 176 of 905 (19%) and 383 of 1,714 (22%).
Each of those emails named a company the reader may have left. That looks careless in the first line. Why cold emails get no replies covers the other causes.
Lists also go stale on their own. Instantly, which sells cold email software, says B2B email lists decay at 2.1% a month (Instantly, April 2026, checked 16 October 2026). That is Instantly's claim, not ours, and the article names no study.
Your file never leaves your browser. Nothing is uploaded. Your browser's own file reader opens the CSV and the comparison runs in memory. Open your browser's network panel while it runs: no request carries your data. Once the page has loaded, it works offline. Like every page here, it counts one page view, which holds the page address and the referring site and nothing from your file.
A mismatch is a flag to check, not proof someone left. Innocent causes I see often:
acme.co.uk against acme.com. The table marks these as same name, different ending.Check a sample on LinkedIn before you delete anything. Then find the right person at the current company, or drop the row.
It reads CSV only, so export from Excel or Google Sheets first. It needs a website or domain column. It does not test whether an address exists, so run a verifier too. The table shows the first 200 flagged rows; the download holds all of them.
Our own reply, bounce and data-decay figures are in cold email statistics, and positive replies by vertical in cold email positive reply rate. To check the rest of your outbound, run the free GTM teardown.
Compare each contact's email domain with their company's website domain. Where they differ, the address often belongs to a past employer. Load your CSV above, confirm the two columns, download the flagged rows, and check a sample by hand.
No. Your file never leaves your browser. The CSV is read and checked on your own device, and no request sends any of it to us or to anyone else.
I can only give you ours. In two B2B client campaigns audited on 8 October 2026, the mismatch rate ran from 18% to 24% per list. That is one audit, not an industry benchmark.
Not automatically. A founder at a small firm may use Gmail. But a free-mail address tells you nothing about the company, so confirm the person before you send.