Last reviewed September 16, 2026

Find out whether a fax line works

Enter the number of the fax machine or service you want to check and we send it one page, at no charge, usually inside a minute. This tests whether the line receives; to test whether your own machine sends, fax our test number instead. The page carries legibility and resolution targets, so it answers whether the fax arrived readable rather than only whether it arrived, and the transmission record — what was dialed, when, and whether the receiving system acknowledged the page — goes to the email address you give.

Send one

Both fields are required: the number is what is being tested, and the address is where the record goes. A test that does not go through does not count against you — try the same number again once the machine is ready.

This tests one direction: whether the number you enter can receive. If what you need to know is whether your own machine can send, fax our test fax number instead and we will show you what arrived.

What the page carries

A printer’s test page exists to show whether the output is any good, not only whether something came out. This one does the same for a fax line.

Record: The record ID, the time it was sent and the number it went to, so the sheet in the tray can be matched to the record on screen.
Legibility: The same sentence at six sizes, from 14 point down to 5. If a line is not readable on paper, text at that size will not survive this fax line.
Resolution: Line pairs at four pitches, drawn horizontally and vertically. A fax pixel is taller than it is wide, so the two can resolve differently — and a machine that merges the finest pair is showing you its limit.
Halftone: Dot patterns at five densities. How the lighter patches come through is how a photograph or a signature would.
Registration: Marks inside each corner. A machine that crops or skews shows it here first.

If nothing arrives

The status page and the record say which of these happened, in the carrier’s own terms. A busy line is retried twice, a few minutes apart. A line that answers but never produces a fax tone is usually a telephone rather than a fax machine, or a machine that is off, out of paper, or set to answer manually. A number that does not connect at all is worth checking digit by digit against whatever it was copied from.

A test that fails costs nothing. A test that did not go through does not use up the day's confirmed test for that number, but it does count as one of the 3 tries a number gets each UTC day. Fix what the record points at and send another.

What we keep

The page is generated here — nothing of yours is uploaded. The record keeps the number dialed, the time, the outcome and the address the record was sent to, and the page itself is deleted 24 hours after transmission, as with every fax sent through this site. The address is used for the record and for nothing else. There is no account, nothing recurring, and no marketing list; the privacy policy is the full statement.

Why there is no charge

A single page costs us well under a cent to send, and every test tells us how a real receiving machine behaves — which is worth more to a service that sends faxes for a living than the price of the page. If the test shows your line works and you have a document to send down someone else’s, that is what the button below does.

$4.99, charged once. No account. No subscription.