The basic process: email to fax gateway

To send a fax using email, you compose a message to a special fax number formatted as an email address, attach your document, and send it like a normal email. The fax gateway service converts your email into a fax transmission and delivers it to the recipient's fax machine. No fax machine, fax line, or special software on your end is required — only an email account and a document file.

The recipient receives the fax on their fax machine exactly as if you had sent it from a traditional fax device. They see your document printed out, and the transmission appears in their fax machine's log. From their perspective, nothing is different.

Key Takeaways

  • You send an email to an address formatted like 1-555-123-4567@faxgateway.com, where the fax number becomes part of the email address.
  • Your document must be attached as a file — typically PDF, Word, or image format — not pasted into the email body.
  • Some services are free for a limited number of faxes per month; others charge per page or require a subscription.
  • The fax arrives within minutes, and you receive a confirmation email showing whether the transmission succeeded.
  • You need the recipient's fax number and their fax machine must be powered on and have paper loaded.

Finding a fax gateway service

Common fax gateway services include eFax, MyFax, Fax.plus, and Google Fax (through Google Workspace). Each has a different format for the email address you send to, so check the service's documentation for the exact syntax. Some services let you send to any fax number; others require you to register the recipient's number first.

Free options exist but usually come with limits. Google Fax allows one free fax per day if you have a Google Workspace account. Some services offer a small number of free faxes monthly, then charge for additional ones. Paid services typically cost between $5 and $20 per month for unlimited faxes, or you can pay per page (usually $0.10 to $0.25 per page) without a subscription.

Before choosing a service, confirm it supports the file format you plan to send. Most accept PDF, JPEG, PNG, and Microsoft Word files. If you need to send a paper document, you will need to scan it first using a scanner or a smartphone scanning app.

Preparing your document

Save your document in a format the gateway accepts. PDF is the safest choice because it preserves formatting and works with every service. If you are scanning a paper document, use your scanner's software or a free app like Adobe Scan or Microsoft Lens to create a PDF or image file.

Check that your document is readable. Fax machines have lower resolution than computer screens, so very small text or light colors may not come through clearly. If you are sending a scanned document, make sure the scan is straight and the text is dark enough to read. Test with a short document first if you are unsure.

Keep file size in mind. Most services accept files up to 10 or 20 megabytes, but smaller is better — a 50-page document should be under 5 megabytes. If your file is too large, compress it or split it into multiple emails.

Composing and sending the fax email

Create a new email in your email client. In the "To" field, enter the fax number in the format your service requires. For eFax, this might be 1-555-123-4567@efax.com. For Fax.plus, it might be +1-555-123-4567@fax.plus. Check your service's help page for the exact format — using the wrong format will cause the email to bounce.

The subject line becomes the fax cover page title, so use something descriptive like "Invoice #12345" or "Tax Return 2024". Leave the email body blank or add a brief note — the fax gateway will ignore the body text and send only the attachment.

Attach your document file. Do not paste the document into the email body; it must be a separate file attachment. Click "Send" and wait for a confirmation email from the fax service, usually arriving within a few minutes. The confirmation will tell you whether the fax was sent successfully or if there was an error.

What happens if the fax fails

If the recipient's fax machine is off, out of paper, or has a busy signal, the fax gateway will typically retry automatically several times over a few hours. You will receive a failure notification email if the fax cannot be delivered after all retries are exhausted.

Common reasons for failure include an incorrect fax number, the recipient's fax line being disconnected, or the fax machine being in an error state. Ask the recipient to confirm their fax number and that their machine is powered on and ready to receive. Then resend the fax.

If you are sending to a business, call ahead to let them know a fax is coming. Many offices monitor fax machines less frequently than email, so a quick phone call ensures someone will be there to retrieve it.

Receiving faxes via email

Most fax gateway services also let you receive faxes via email. When someone sends a fax to your service's fax number, the gateway converts it to a PDF and emails it to you. This means you can receive faxes without owning a fax machine or fax line.

To set this up, you create an account with the service and are assigned a fax number. You give that number to people who need to send you faxes. Incoming faxes arrive in your email inbox as attachments, usually within minutes of being sent.

Cost comparison and alternatives

If you only send a fax occasionally, a free or pay-per-fax service makes sense. Google Fax is free if you have Google Workspace; Fax.plus and eFax offer small free monthly allowances. For regular faxing, a monthly subscription ($5 to $20) is usually cheaper than paying per page.

If you need to send many faxes regularly, some services offer volume discounts or business plans. Compare the cost of a fax gateway subscription against the cost of a traditional fax machine and phone line — for most people, email faxing is far cheaper.

Another option is to ask the recipient if they can receive documents by email or a file-sharing service instead. Many organizations still require faxes for legal or compliance reasons, but some will accept PDF attachments or links to cloud storage. This avoids the fax gateway entirely and is often faster.

Frequently Asked Questions

Can I send a fax to an international number?

Yes, most fax gateway services support international fax numbers. Include the country code in the fax number — for example, +44-20-7946-0958 for a London number. International faxes may cost more per page than domestic ones, so check your service's pricing before sending.

What file formats work best for faxing?

PDF is the most reliable because it preserves formatting and works with all services. JPEG and PNG image files also work well. Avoid sending Word documents or Excel files directly if possible — convert them to PDF first to may support the recipient sees exactly what you intended.

How long does it take for a fax to arrive?

Most faxes arrive within 2 to 5 minutes after you send the email. You will receive a confirmation email from the gateway showing success or failure. If the recipient's fax machine is busy or off, the gateway will retry automatically, which may take longer.

Do I need to include a cover page?

No, but you can. The subject line of your email becomes the fax cover page title. If you want a formal cover page with your name, company, and contact information, some services let you create a template in your account settings.

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

The fax will be delivered to whoever owns that fax number. There is no way to recall it once sent. Always double-check the fax number before hitting send, especially if the document contains sensitive information. If you make a mistake, contact the recipient when ready and ask them to discard the fax.