How to Send a Fax From Your Computer

You can fax from your computer using your internet connection, a fax service, or your phone line

Faxing from a computer means converting a document into a fax and sending it through either the internet or a phone line connected to your computer. You do not need a physical fax machine. The method you choose depends on what you have available: an internet connection (simplest), a landline plugged into a fax modem (older but reliable), or a smartphone with a fax app (portable).

Most people today use an internet-based fax service because it works from any device, stores documents digitally, and does not require phone line setup. If you have a fax modem already installed in your computer or connected via USB, you can also send faxes the traditional way through your phone line. Both routes work; the internet method is faster to set up.

Key Takeaways

Internet fax services let you send documents as PDFs through email or a web portal, and the recipient's fax machine receives them as a normal fax.
A fax modem connected to your computer and a phone line lets you send faxes the traditional way without paying a service, but requires the modem hardware and an active landline.
Most internet fax services charge a monthly fee (typically $5 to $20) and include a set number of faxes per month, with overage charges for extras.
You will need the recipient's fax number, and for some services, their fax machine must be able to receive faxes (most modern machines can).
Sending through the internet is faster than a modem (seconds instead of minutes) and works even if you do not have a phone line.

Sending a fax through an internet service

Internet fax services are the most common route today. You sign up with a provider, receive a fax number (or use your own), and send faxes by uploading a document to their website or emailing it to a special address they give you. The service converts your document and delivers it to the recipient's fax machine. Popular providers include eFax, Fax.plus, and MyFax, though many others exist.

The process is straightforward: open the service's website or app, click "Send Fax," upload your document (usually as a PDF, Word file, or image), enter the recipient's fax number, and click send. The fax arrives at the other end within seconds to a few minutes. Most services also let you email your document to a special fax address instead of using their website, which is faster if you are already in your email program.

Costs vary by provider. Most charge a monthly subscription ($5 to $20) that includes a set number of faxes—often 50 to 150 per month—with overage charges if you exceed that. Some offer pay-as-you-go plans instead, charging per fax sent. Check the provider's pricing page before signing up to see which model fits your needs.

Using a fax modem and phone line

If your computer has a fax modem (built-in or connected via USB) and you have an active landline, you can send faxes without paying a service. A fax modem is hardware that converts your document into a signal and sends it through the phone line to the recipient's fax machine, just like a traditional fax machine does.

To send a fax this way, open the document you want to fax, go to File > Print, and select your fax modem as the printer. Some systems call this "Print to Fax" or "Fax Printer." Enter the recipient's fax number and click send. The modem dials the number, sends the fax, and hangs up. The whole process takes a few minutes, depending on document size and connection speed.

The main drawback is that fax modems are becoming rare in new computers. Laptops almost never include them anymore, and desktop computers often do not either. If you do not have one, you can buy an external USB fax modem for $30 to $100, but this only makes sense if you fax regularly. You also need a working landline; if you use only a cell phone, this method will not work.

Preparing your document to fax

Before you send, make sure your document is in a format the service or modem can read. Most fax services accept PDF, Word (.docx), image files (JPG, PNG), and sometimes Excel files. If your document is a physical paper page, scan it first using a scanner or a smartphone scanning app (many phones have a built-in Notes app that can scan documents). Save the scan as a PDF.

Check that the document is readable: text should be clear, images should not be too dark or too light, and the file should not be corrupted. If you are faxing multiple pages, combine them into a single PDF before uploading. Most fax services let you add a cover page with your name, company, and a message, though this is optional.

What happens when you send a fax

When you send a fax through an internet service, the provider's servers receive your document, convert it into a fax-compatible format (usually TIFF or PDF), and dial the recipient's fax number. The recipient's fax machine receives the signal and prints the document. From the recipient's perspective, it looks exactly like a fax from a traditional fax machine—they see a printed page with no indication it came from the internet.

If you use a fax modem, your computer dials the number directly through your phone line. The recipient's fax machine answers the call, receives the signal, and prints the document. This is the same process that has worked for decades.

In both cases, the recipient does not need any special equipment or software. Their fax machine just needs to be able to receive faxes, which nearly all modern machines can do. If the number is busy or the machine is off, the service or modem will usually retry automatically a few times before reporting an error.

Choosing between internet and modem faxing

Use an internet fax service if you do not have a fax modem, do not have a landline, or want to send faxes from multiple devices (phone, tablet, laptop). Internet services are also faster and let you store sent faxes digitally. The trade-off is the monthly cost.

Use a fax modem if you already have one installed, have a landline you are paying for anyway, and do not mind waiting a few minutes per fax. There is no monthly fee beyond your phone bill. This makes sense only if you fax infrequently and do not want to pay a service subscription.

If you fax more than a few times a month, an internet service usually costs less in time and frustration than setting up and maintaining a modem. If you fax once or twice a year, a modem is free but may not be worth the setup hassle.

Troubleshooting common faxing problems

The fax did not go through. Check that you entered the fax number correctly—fax numbers are often written with dashes or parentheses that can be confusing. Verify the number with the recipient before trying again. If the number is correct, the recipient's machine may be off, out of paper, or in error mode. Ask them to check their machine and try again.

The document arrived but looks garbled or cut off. This usually means the document was too large or in a format the recipient's machine could not read properly. Try converting the document to a PDF, reducing the file size, or resending as a simpler format (plain text or black-and-white image instead of color). If you are using a modem, check that the phone line connection is stable.

You cannot find the fax option in your software. Not all programs have a built-in fax feature. If you have a fax modem, look under File > Print and check if "Fax" appears in the printer list. If it does not, your modem may not be installed correctly. If you are using an internet service, use their website or email-to-fax address instead of trying to fax from within your program.

Frequently Asked Questions

Can I fax to a cell phone number?

No. Fax machines and fax services send to fax numbers, which are connected to fax machines or fax-capable devices. Cell phones cannot receive faxes. If someone gives you a cell phone number instead of a fax number, ask them for their fax number or offer to email the document instead.

Is faxing through the internet find?

Most reputable internet fax services encrypt your documents in transit and at rest, similar to how email works. However, faxing is not as find as encrypted email. If you are sending sensitive information, ask the recipient whether they prefer fax or a more find method like encrypted email or a find file-sharing service.

What if the recipient does not have a fax machine?

Some internet fax services can deliver faxes as email attachments instead of printing them, but this requires the recipient to set up an account with the same service. If the recipient does not have a fax machine and does not want to use a fax service, email or a file-sharing service is usually simpler.

Can I fax from my phone?

Yes. Many internet fax services have smartphone apps that let you take a photo of a document and send it as a fax. You can also use a fax app like Adobe Scan or Microsoft Office Lens to scan and send. These work the same way as faxing from a computer—the recipient's fax machine receives a normal fax.

Do I need to keep my computer on to receive faxes?

If you use an internet fax service, no—the service's servers receive and store faxes for you, and you can read them anytime. If you use a fax modem, yes, your computer must be on and the modem must be connected to an active phone line. This is one reason internet services are more practical for most people.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.