Does this send an email?

No, it only validates format and domain structure to reduce obvious errors.

What does “valid” mean here?

It means the address follows syntax rules and the domain appears well-formed.

Why can a valid address still bounce?

Mailbox availability is not guaranteed without a direct SMTP check.

Does 'Valid Syntax' mean the email address definitely exists?

No. This tool checks the *format* (syntax) of the email, not its *existence*. A 'Valid Syntax' result means the email *could* exist, but it doesn't guarantee it. Verifying existence requires a separate, server-side check (like an SMTP ping) which this tool does not perform, to protect your privacy.

What is the difference between this tool and a paid email verifier?

This tool performs client-side syntax validation. Paid verifiers perform server-side verification, which involves checking the domain's MX records and pinging the mail server to see if the specific mailbox (e.g., 'john.doe') exists. Our tool is instant and 100% private; paid tools are more thorough but require sending your data to a third-party server.

Is this tool safe to use? Is my email address saved?

Yes, this tool is 100% safe and private. All validation happens directly in your browser (client-side). Your email address is *never* sent to our server or any third-party server. Nothing is logged or saved.

MX (Mail Exchanger) records are special DNS records that tell the world which mail servers are responsible for accepting email for a specific domain. A valid domain must have MX records to receive email.

Why did my email fail the syntax check?

Common reasons for failure include: missing the '@' symbol, having spaces in the address, missing a top-level domain (like '.com' or '.org'), or using special characters incorrectly (e.g., '..' or starting with a '.').

What is a 'disposable' email address?

A disposable email address is a temporary, throwaway address used to sign up for services without revealing a real email. While they have valid syntax, we flag them because they are often used to abuse systems and are not good for long-term contact.

Email Validator - Check Email Address Syntax & Format

Instantly check if an email address is formatted correctly with our free Email Validator. Validates syntax against RFC 5322 standards. 100% client-side and private.

Full original guide (expanded)

Audit: Needs review

Formula (LaTeX) + variables + units

This section shows the formulas used by the calculator engine, plus variable definitions and units.
Note: This page needs review to confirm formulas and sources.

No formulas provided in audit spec.

Variables and units

No variables provided in audit spec.

Sources (authoritative):

Email Validator — calcdomain.com · Accessed 2026-01-21
https://calcdomain.com/email-validator

Changelog

Version: 0.1.0-draft
Last code update: 2026-01-21

0.1.0-draft · 2026-01-21

Initial audit spec draft generated from HTML extraction (review required).
Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
Confirm sources are authoritative and relevant to the calculator methodology.

Verification pending · Last code update: 2026-01-21

Formulas

(Formulas preserved from original page content, if present.)

Version 0.1.0-draft

Citations

Add authoritative sources relevant to this calculator (standards bodies, manuals, official docs).

Changelog

0.1.0-draft — 2026-01-19: Initial draft (review required).