The simplest way to fax from email
You can send a fax directly from your email without owning a fax machine or paying for a separate fax service. Most email providers work with fax-to-email gateways — services that convert your email into a fax and deliver it to a standard fax number. The process takes the same steps as sending an email: you address it to a fax number (reformatted as an email address), attach your document, and send.
The most common gateway is FaxZero, which is free for up to five faxes per month within the United States. Other options include eFax, Google Fax (through Google Voice), and services built into Microsoft 365 and some business email plans. Each works slightly differently, so the method you choose depends on how often you need to fax and whether you want to keep a record of what you sent.
Key Takeaways
- You send a fax through email by converting the fax number into an email address using your gateway's format — for example, FaxZero uses 1234567890@faxzero.com.
- The document you want to fax goes in the email attachment, not the message body, and must be in PDF, Word, or image format.
- FaxZero is free for five faxes per month; beyond that you pay per fax, and other services charge monthly or per-fax fees.
- Your email provider does not send the fax itself — the gateway receives your email, converts it, and dials the fax number on your behalf.
- Faxes sent through email gateways arrive at the receiving fax machine looking like a standard fax, with no indication they came from email.
How to send a fax using FaxZero
FaxZero is the most straightforward option if you fax occasionally and do not want to pay. Open your email and create a new message. In the "To" field, type the fax number you are sending to, followed by @faxzero.com. For example, if the fax number is 555-123-4567, you would type 5551234567@faxzero.com (use only the digits, no dashes or spaces).
Attach the document you want to fax. FaxZero accepts PDF files, Word documents, images (JPG, PNG), and several other formats. Do not paste the document into the email body — it must be an attachment. Add a subject line if you want, though it will not appear on the fax itself. Leave the message body blank or add a brief note; FaxZero will include it as a cover page.
Send the email. FaxZero will receive it, convert the attachment to fax format, and dial the number within a few minutes. You will get a confirmation email telling you whether the fax went through. If it failed, FaxZero will say why — usually because the number was wrong or the receiving fax machine was offline.
Using Google Fax through Google Voice
If you have a Google Voice number, you can fax through Google's system without a separate service. This works only if you have already set up Google Voice on your account. Open Google Voice, click the menu, and select "Settings." Go to the "Calling" tab and turn on "Fax." This adds fax capability to your Google Voice number.
To send a fax, open Gmail and compose a new email to the fax number in this format: 1-555-123-4567@ifax.goog (replace the number with the actual fax number). Attach your document and send. Google will convert it and send it from your Google Voice number. You will see a confirmation in Gmail when it completes.
Google Fax is free and works well if you already use Google Voice, but it has limits: you can send only a few faxes per day, and the receiving fax machine will see your Google Voice number as the sender rather than a business number.
Faxing through Microsoft 365 and other email services
Microsoft 365 subscribers can fax through Outlook using the Microsoft Fax service, though it is not turned on by default. Check your Outlook settings under "Mail" and look for "Fax" or "Faxing options." If available, you will see instructions for formatting the fax number as an email address.
Some business email plans from providers like Zoho Mail and Nextiva include fax-to-email built in. Check your email provider's help documentation or settings to see whether faxing is available. If it is, the process is the same: format the fax number as an email address and attach your document.
What documents work best for email faxing
PDF files are the most reliable format for faxing through email. They preserve formatting, print cleanly, and work with every gateway. If you have a Word document, export it as a PDF before attaching it — this prevents formatting problems when the gateway converts it.
Images (JPG, PNG) also work, but they must be clear and readable. If you are faxing a scanned document or a photo of a paper, make sure the text is dark and the background is white. Blurry or low-contrast images may not fax clearly. Most gateways will reject files larger than 10 to 25 megabytes, so compress large PDFs if needed.
Do not try to fax a document by pasting it into the email body. Gateways only convert attachments, so the text in your message will not reach the fax machine. Always use the attachment field.
Cost and limits for different services
| Service | Cost | Monthly limit | Best for |
|---|---|---|---|
| FaxZero | Free for 5 faxes/month; $0.10–$0.25 per fax after | 5 free faxes | Occasional faxing |
| Google Fax (Google Voice) | Free | A few per day | Light use, existing Google Voice users |
| eFax | $9.99–$19.99/month | Varies by plan | Regular business faxing |
| Microsoft Fax (365) | Included with Microsoft 365 | Varies | Microsoft 365 subscribers |
Choose based on how often you fax. If you fax fewer than five times a month, FaxZero's free tier covers you. If you fax regularly for work, a paid service like eFax gives you a dedicated fax number and keeps a record of all sent and received faxes. Google Fax is free but best for very light use because of daily limits.
Troubleshooting faxes that do not go through
If your fax fails, the gateway will send you an error message. The most common reasons are a wrong number, a receiving fax machine that is offline or out of paper, or a document that is too large. Check the fax number against the original source — fax numbers are straightforward to mistype because they look like phone numbers but are not.
If the receiving fax machine is offline, try again in a few hours. Some offices turn off fax machines at night or on weekends. If your document is very large (more than 20 pages or several megabytes), split it into smaller files and send them separately.
If you are using FaxZero and the fax fails repeatedly, check that you formatted the number correctly — digits only, no dashes or spaces. If you are using Google Fax, remember that you can send only a few per day, so wait before retrying.
Frequently Asked Questions
Can the person receiving the fax tell it came from email?
No. The fax arrives at their machine looking like a standard fax. It will show your name or the sender information you provided, but not that it came through email. To them, it is indistinguishable from a fax sent from a traditional fax machine.
What if I need to fax something that is not a document, like a signed check or a photo?
Take a clear photo or scan of the item and save it as a JPG or PDF. Attach it to your email just as you would a document. Make sure the image is sharp and the text or signature is readable. Blurry photos may not fax clearly.
Do I need to set up an account before I can fax through email?
FaxZero and Google Fax do not require an account — you just send the email. Paid services like eFax and Microsoft Fax require you to sign up and configure your account first. Check your email provider's settings to see whether faxing is already available.
Can I fax to an international number?
Most free gateways like FaxZero only fax within the United States. Paid services like eFax support international faxing, but you will pay a higher per-fax fee. Check your gateway's supported countries before trying an international number.
What happens if I fax the same document to multiple numbers?
Send separate emails to each fax number. Each email counts as one fax toward your monthly limit. If you are using FaxZero's free tier and need to send to five different numbers, that uses all five of your free faxes for the month.