Use the free Email Address Validator below: your data never leaves your browser — all work happens on your device, and nothing is uploaded to any server.
What “Valid” Means Here
An email address can be wrong in two different ways. It can be written incorrectly, with a typo, a missing part, or an illegal character. Or it can be written correctly but belong to nobody, because the mailbox does not exist. The tool above checks only the first kind of problem: the syntax and shape of the address. It reads the address piece by piece and reports each check separately, so you can see exactly what failed instead of getting a bare yes or no.
That limit is deliberate and honest. No web page can reliably tell you whether a mailbox exists without sending mail to it, and services that claim to do so are usually guessing from the domain or from old data. A syntax check is still very useful: most bad addresses in forms, mailing lists, and contact sheets are typos and formatting slips, and those are exactly what this tool catches.
The Anatomy of an Address
Every address has three parts: a local part before the @ sign, the @ sign itself, and a domain after it. The local part names the mailbox, and it may contain letters, digits, and a set of special characters including dots, plus signs, and hyphens. It may not start or end with a dot, and it may not contain two dots in a row. Its length is limited to 64 characters.
The domain names the mail server. It is made of labels separated by dots, like “mail”, “example”, and “com”. Each label may contain letters, digits, and hyphens, but may not start or end with a hyphen, and each label is at most 63 characters. The last label, the top-level domain, must be at least two letters. The whole address may be at most 254 characters. The tool checks every one of these rules and shows the result per rule.
How to Use the Tool
Paste or type the address and press Validate. A table appears with a tick or a cross for each rule, plus a verdict at the top. If the domain looks like a common typo, for example “gmai.com” instead of “gmail.com”, the tool suggests the likely correction. That suggestion is a guess based on well-known providers, so treat it as a hint to double-check, not as proof.
Use it when cleaning a mailing list, checking a signup form entry, or verifying an address someone dictated over the phone. It is especially handy for catching the classic slips: a missing @, a space sneaked in from copy and paste, a dot at the end, or a domain typed as “example.comm”.
Common Mistakes It Catches
Spaces are the most common invisible error, often added when copying from a document or a chat message. Double dots come from fast typing or from a name typed as “first..last”. A trailing dot after the domain looks harmless but makes the address invalid. Two @ signs appear when someone pastes “name@old.com@new.com” or confuses the address with a login name. Each of these passes a quick glance but fails delivery, and each is flagged separately by the tool.
Another frequent mistake is confusing similar characters: a zero for the letter O, or a one for a lowercase L, usually inside the domain. Syntax checking cannot catch those, because the result is still a valid address, just the wrong one. For those cases, the only real test is sending a confirmation message and asking the owner to click it.
What a Valid Result Does Not Prove
A valid verdict means the address is well formed. It does not mean the domain accepts mail, the mailbox exists, or the owner is who you think. A perfectly formed address at a made-up domain is still undeliverable. Conversely, some real addresses use unusual but legal forms, such as a plus tag like “name+shop@example.com”, which many sites accept for filtering. The tool accepts those, because they are legal, even though some older forms reject them wrongly.
If you run a signup form, pair syntax checking with a confirmation email. That two-step process, check the shape instantly and confirm ownership by email, is the standard for a reason: it catches typos fast and proves ownership reliably, without ever needing to guess whether a stranger’s mailbox exists.
Tips for Cleaner Lists
When importing addresses, trim spaces first, convert the domain to lowercase, and reject empty rows before validating. Keep a list of the exact failures rather than deleting rows silently, because a bulk import can hide a systematic error, like a column shifted by one, that turns hundreds of good addresses bad. Validate again after any spreadsheet edit, because sorting and filtering are classic ways to corrupt a column.
Finally, respect privacy. An address is personal data. Validate it where you already have a legitimate reason to hold it, do not test other people’s addresses out of curiosity, and never paste a list of customer addresses into an unknown online service. This tool runs entirely in your browser, so the addresses you check here are never uploaded anywhere.