The basic process: email to fax gateway

You can send a fax through email by using an email-to-fax gateway — a service that converts your email message and attachments into a fax and delivers it to a fax machine on the other end. You write an email as you normally would, attach the document you want to fax, address it to a special fax number formatted as an email address, and send it. The gateway receives it, converts the content, and transmits it to the recipient's fax machine.

The recipient sees a standard fax on their machine — they do not receive an email. From their perspective, a fax came through their phone line. This matters because many businesses and government offices still rely on fax machines and expect documents to arrive that way, even though the document originated as an email on your end.

You do not need to own a fax machine, a fax modem, or special software. You only need an email account and access to the document you want to send, usually as a PDF, image file, or Word document.

Key Takeaways

  • Email-to-fax gateways let you send a fax from your regular email account by addressing it to a special fax-number email address provided by the service.
  • The recipient receives a fax on their fax machine, not an email, so this method works when you need to send documents to businesses or offices that only accept faxes.
  • Free services like Google Fax, Microsoft 365 fax features, and some online fax platforms offer limited free sends per month; paid plans remove limits and add features like fax storage.
  • Supported file formats usually include PDF, JPEG, PNG, TIFF, and Word documents; check your service's requirements before sending.
  • The fax number you send to must be a real, active fax line — sending to an incorrect or inactive number will fail silently or bounce back.

Free services built into email accounts

Google Workspace (formerly G Suite) includes a fax feature for business accounts. You compose an email in Gmail, attach your document, and send it to a special address in the format +1[fax-number]@gmail.com. Google converts the attachment and sends it as a fax. Free Google Workspace accounts get a limited number of free fax pages per month; paid tiers include more.

Microsoft 365 subscribers can send faxes through Outlook using the Fax feature in Microsoft 365. The process is similar: you compose a message, attach the document, and address it using the fax number format provided by Microsoft. The number of free fax pages varies by subscription level.

Both services require you to have an active account with them. If you use Gmail or Outlook for personal email but do not have a paid business subscription, you may not have access to fax features, or they may be limited to a small number of free sends.

Standalone online fax services

Dedicated fax services like eFax, Fax.plus, HelloFax, and Faxburner operate independently of your email provider. You sign up for an account, and the service assigns you an email address or fax number. You then send emails to that address with your documents attached, and the service converts and transmits them as faxes.

Most of these services offer a free tier with a limited number of faxes per month — typically between 1 and 5 free sends. Paid plans remove the limit and often add features like fax storage, the ability to receive faxes, and integration with cloud storage services like Google Drive or Dropbox.

The advantage of standalone services is that you can use them with any email account — Gmail, Outlook, Yahoo, or a work email. You are not locked into a specific email provider. The disadvantage is that you may need to create yet another account and remember another login.

Step-by-step: sending a fax through email

First, prepare your document. Save it as a PDF, JPEG, PNG, or TIFF file. Most services accept these formats; some also accept Word documents or Excel files. Make sure the document is clear and readable — if it is a scan, check that the text is not too faint or blurry.

Second, open your email and compose a new message. Attach the document file. In the "To" field, enter the fax number in the format your service requires. If you are using Google Fax, the format is +1[area code][fax number]@gmail.com. If you are using a standalone service, the service will give you a specific email address to send to. Double-check the fax number — a single digit wrong means the fax goes to the wrong place or fails.

Third, add a subject line and a brief message if needed. Some services ignore the subject and message body and send only the attachment, but it is good practice to include them anyway. Then send the email as you normally would.

Fourth, wait for confirmation. Most services send you a confirmation email within a few minutes saying whether the fax was sent successfully. If the fax number was invalid or the fax machine was offline, you will usually get a failure notice. Keep that confirmation email in case you need proof that you sent the fax.

File formats and document requirements

The most reliable format is PDF. Nearly all fax services accept PDFs, and the format preserves the layout and fonts of your original document. If you have a Word document, export it as a PDF before sending rather than attaching the Word file directly.

Image files like JPEG and PNG work, but they may not compress as well as PDFs, which can affect file size and transmission speed. TIFF files are also widely accepted and are actually the standard format for faxes, so if your service accepts TIFF, that is a safe choice.

Most services have a file size limit, usually between 10 and 25 megabytes per fax. A typical multi-page document is well under that limit. If you are sending many pages or high-resolution scans, check your service's limits before sending. Some services also limit the number of pages per fax — often 50 to 100 pages — so if you are sending a very long document, you may need to split it into multiple faxes.

Common problems and what to do

The fax number is wrong or inactive. If you send a fax to a number that does not exist or is no longer in service, the fax will fail. You will usually get a bounce-back email from the service saying delivery failed. Always verify the fax number with the recipient before sending — ask them to confirm it in writing or check their official website or letterhead.

The fax machine is offline or out of paper. If the recipient's fax machine is broken, offline, or out of paper, the fax may fail to deliver. Some services will retry automatically a few times over several hours. If you do not get a confirmation email after a few hours, contact the recipient by phone to confirm they received it, or ask them to check their fax machine.

The document did not convert properly. Occasionally a document will not convert to fax format correctly — text may be garbled, images may not appear, or the layout may be wrong. This usually happens with complex Word documents or PDFs with embedded fonts. If this happens, try converting the document to a straightforward PDF or a JPEG image and resending.

You exceeded your free fax limit. If you use a free service and send more faxes than your plan allows, the service will reject the fax and tell you to upgrade or wait until your limit resets. Check your service's terms to see when the limit resets — usually monthly.

When to use email-to-fax versus other methods

Email-to-fax works best when the recipient has a fax machine and expects to receive documents that way. Government offices, law firms, medical practices, and many businesses still use fax machines as their primary document intake method. If you need to send something to one of these places, email-to-fax is often the fastest and most reliable route.

Email-to-fax is less useful if the recipient has an email address and can receive documents digitally. In that case, sending the document directly by email is simpler and faster. But if they only provide a fax number, email-to-fax is your solution.

If you need to send faxes regularly — more than a handful per month — a paid fax service may be worth the cost. It removes the limit on free sends and often adds features like the ability to receive faxes, store them in the cloud, and integrate with other tools you use.

Frequently Asked Questions

Do I need to own a fax machine to send a fax through email?

No. An email-to-fax gateway converts your email and attachment into a fax signal and sends it to the recipient's fax machine. You only need an email account and the document you want to send.

What if the recipient does not have a fax machine?

Email-to-fax only works if the recipient has an active fax machine connected to a phone line. If they do not, ask them for an email address instead and send the document directly. Many organizations now accept email as an alternative to fax.

How long does it take for a fax to go through?

Most faxes transmit within a few minutes of you sending the email. You will usually get a confirmation email from the service within 5 to 15 minutes. If the fax fails, you will get a failure notice at the same time.

Can I send a fax to an international fax number?

Yes, most services support international fax numbers. Use the full international format: the plus sign, country code, area code, and fax number. For example, +44 20 7946 0958 for a UK number. Check your service's pricing — international faxes may cost more than domestic ones.

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

The fax will be delivered to whoever owns that fax machine. You cannot recall it once it has been sent. If you realize you sent it to the wrong number, contact the service when ready to see if they can intercept it, though this is rarely possible. Always double-check the fax number before sending.