The basic process: email to fax gateway

To send a fax by email, you compose a message to a special email address that converts it into a fax and delivers it to the recipient's fax machine. The address format is usually the recipient's fax number followed by the gateway provider's domain — for example, 5551234567@fax.com. When you send the email with an attachment, the gateway receives it, converts the attachment to fax format, and dials the fax number on the recipient's end.

This method works because fax machines and email gateways speak the same underlying language. The gateway translates your email into the fax protocol, then sends it through the phone line just as a traditional fax machine would. The recipient sees it arrive on their fax machine with no indication it came from email — they only see the faxed document.

You do not need to install software or buy a fax modem. If you have email, you can send a fax this way. Some services are free for a limited number of faxes per month; others charge per page or per fax.

Key Takeaways

  • Email-to-fax gateways convert your email attachment into a fax and send it to a fax machine using the recipient's fax number as the email address.
  • You need the recipient's fax number, not their email address, and the document must be in a format the gateway accepts — usually PDF, Word, or image files.
  • Free services typically allow 1 to 5 faxes per month; paid services charge between $0.25 and $2 per page depending on the provider.
  • The fax arrives on the recipient's machine looking like any other fax, with no way for them to know it came from email.

Finding and choosing an email-to-fax service

Several providers offer email-to-fax gateways. eFax, Fax.plus, HelloFax, and Faxburner are among the most common. Each has a different pricing model: some charge a monthly subscription, some charge per fax, and some offer a free tier with limits. Before signing up, check how many free faxes the service allows per month and whether you need to create an account or can send when ready.

Some services require you to register and log in before sending your first fax. Others let you send a fax to a temporary address without an account, though you will not be able to track delivery or resend if something goes wrong. If you send faxes regularly, an account is worth the setup time because you can see whether the fax was delivered and keep a record of what you sent.

Check the file formats each service accepts. Most accept PDF, Word documents (.doc, .docx), and image files (JPG, PNG, TIFF). Some also accept plain text or email body text without an attachment. If you are faxing a scanned document, make sure the file size is not too large — most services have a 10 to 25 MB limit per fax.

Preparing your document and composing the email

Before you send, convert your document to PDF if possible. PDFs preserve formatting better than Word documents and are accepted by every email-to-fax service. If you are faxing a scanned document, make sure the image is clear and readable — fax machines compress images, so a blurry scan may arrive unreadable on the other end.

Compose your email as you normally would, but put the recipient's fax number in the "To" field instead of an email address. The format depends on the service you are using. Most use the pattern faxnumber@servicedomain.com. For example, if you are using eFax and sending to fax number 555-123-4567, the address might be 5551234567@efax.com. Check the service's website for the exact format before you send.

You can include a message in the email body, and most services will print it as a cover page or header on the fax. Keep the message brief — fax machines have limited space and some services charge by the page. Attach your document and send the email as you normally would.

What happens after you send

The gateway receives your email, converts the attachment to fax format, and dials the recipient's fax number. This usually happens within a few minutes, though during busy times it may take up to an hour. If the line is busy or the fax machine is offline, the gateway will retry — most services attempt delivery 2 to 5 times over several hours before giving up.

If you have an account with the service, you will receive a confirmation email telling you whether the fax was delivered. If delivery failed, the confirmation will say why — the line was busy, the number was invalid, or the fax machine did not answer. You can then resend or contact the recipient to verify the number.

If you sent through a free or temporary service without an account, you may not receive any confirmation. In that case, follow up with the recipient by phone or email to confirm they received the fax.

Handling fax numbers with extensions or special formats

If the fax number has an extension or requires a pause before dialing, most services let you add codes to the number. A comma usually means "pause for 2 seconds," and a pound sign (#) or asterisk (*) can be used for extensions or menu navigation. For example, 5551234567,,,2@fax.com would dial the main number, pause, then send the extension 2.

Check the service's documentation for the exact codes it supports — not all services handle extensions the same way. If you are unsure, call the recipient's fax line first to confirm the number and extension work, then use those same digits in your email address.

Costs and when to use paid services

Free email-to-fax services usually limit you to 1 to 5 faxes per month. If you send faxes occasionally — a few times a year — a free service is sufficient. If you send more than 5 faxes per month, a paid service becomes cheaper than paying per fax.

Paid services typically charge between $5 and $15 per month for unlimited faxes, or $0.25 to $2 per page if you pay as you go. Some services bundle email-to-fax with fax-to-email (receiving faxes by email), which costs more but is useful if you need both directions. Calculate your typical monthly volume before choosing: if you send 20 pages per month at $1 per page, a $10 monthly plan saves you money.

Troubleshooting common problems

If your fax does not go through, the most common cause is an incorrect fax number. Double-check the number against the recipient's letterhead or website, and verify you used the correct format for your service. If the number is correct but the fax still fails, the recipient's fax machine may be offline or the line may be busy — ask the service to retry or contact the recipient to confirm the machine is working.

If the fax arrives but the formatting looks wrong, the document may have been too large or in an unsupported format. Try converting to PDF or reducing the file size, then resend. If text is cut off at the edges, the original document may have margins that are too small — add margins and try again.

If you are charged for a fax that failed, contact the service's support team with your confirmation email. Most services refund failed faxes if you report them within a few days.

Frequently Asked Questions

Can I send a fax to a fax machine that is also an email printer?

Yes. If the device has both fax and email capabilities, you can send to either the fax number or the email address. Using the fax number through an email-to-fax gateway works the same way as sending to a traditional fax machine — the device receives it on the fax side and prints it.

What if the recipient's fax number has a country code?

Include the country code as part of the number. For example, if the fax is in Canada, use 14165551234@fax.com (1 is the country code for Canada and the US). Check your service's documentation for whether to include the plus sign or leading zeros.

Can I send a fax from my phone?

Yes, if your phone has email. Compose an email on your phone, attach the document, and send it to the fax gateway address just as you would from a computer. Some services also offer mobile apps that make this easier, with a built-in fax number field instead of typing the address manually.

Is email-to-fax find for sensitive documents?

Email-to-fax is as find as regular email and regular fax — the message travels through the internet and phone networks unencrypted unless you use a service that offers encryption. If you are sending sensitive information like medical records or financial documents, check whether the service encrypts the message in transit and at rest.

What happens if I send a fax to the wrong number?

The fax will arrive at the wrong fax machine. If you realize the mistake when ready, contact your service's support team and ask them to cancel the fax before it is sent — this works only if the fax has not been dialed yet. If it has already been sent, contact the recipient at the wrong number and ask them to discard it, then resend to the correct number.