What happens when you fax from a computer
An online fax service (a website that turns your document into a fax signal and sends it down the phone network for you) does the actual work. The person on the other end still sees a normal fax arrive on their machine, whatever you used to send it.
You need two things before you start: the document saved as a file on your computer, and the fax number you are sending it to. You do not need a fax number of your own unless the other side is also going to fax something back to you.
Where the document actually goes
The service converts your file into the format a fax machine expects and dials the recipient's line. Whatever is on the other end, whether that is an actual machine or another online fax service, answers the call and receives the pages as they come through.
Because the call runs over ordinary telephone lines at the point it reaches the recipient, a short document usually takes a minute or two to arrive. Longer documents take longer, and there is no way to speed that part up from your end.
If you have not already worked out whether you need to send a fax at all, it is worth checking first: some of the organisations that ask for one will also accept a signed PDF by email or a secure portal upload instead. There is more on that in Do I Actually Need to Send a Fax?, and the full set of guides is listed in All Guides.
Uploading, entering the number and sending
The steps are the same whatever online fax service (a website that turns your document into a fax signal and sends it down the phone line) you end up using. Once you've settled the document and the recipient's number, sending it takes a few minutes.
- Open the service's sending page in your browser and sign in, or start as a guest if the free tier allows it.
- Upload the document from your computer. Most services let you drag the file in or browse for it, the same way you'd attach a file to an email.
- Enter the recipient's fax number, including the UK dialling code if you're faxing outside your local area.
- Add a cover sheet if the service offers one. It isn't always required, so skip it if the recipient hasn't asked for one.
- Check the preview, then send. You should get a transmission confirmation once the fax has gone through, usually within a few minutes.
File formats
PDF is accepted everywhere and is the safest choice, especially for anything that's been signed. Most services also accept Word documents and common image formats like JPEG. If you've photographed a signed page, it's worth converting it to a PDF first so the layout doesn't shift when it's sent.
Page limits
Free tiers usually cap how many pages you can send before you're asked to pay or create an account. That limit is set by each service and changes from time to time, so it's worth checking the current figure on the service's own page before you upload a long document. If you're still not sure a fax is what's actually needed here, that's worth settling before you send anything, and the page on whether you actually need to send a fax covers how to check.
Can you send a fax from a computer for free
A number of online fax services (websites that turn your document into a fax signal and send it down the phone network for you) offer a small free allowance, usually a handful of pages, to a first-time user. That is genuinely useful if you only have one document to send and never expect to need fax again.
What the free allowance usually covers
Most free tiers are built around a single transmission. You upload your document, enter the fax number, and the service sends it once at no charge, often up to a set number of pages. Beyond that page count, or for a second fax, you are asked to pay or sign up.
The catches worth checking before you start
- An account is usually required, even for the free send, which means handing over an email address and sometimes a phone number.
- Some services ask for card details up front even when the first fax is free, so a subscription can begin automatically if you do not cancel it.
- The free allowance is often a one-off, so it will not help if you need to send more than one document over time.
- Cover sheets, larger file sizes, or certain file types may sit outside the free tier and push you into a paid plan without much warning.
When it is worth paying instead
If you need to send more than one fax, or you want a transmission confirmation you can rely on for a solicitor or a court, a paid single-use option is usually more straightforward than trying to fit the job into a free allowance. Check the service's own pricing page for what a single send actually costs before you commit, since free tier terms change.
Before spending any time comparing services, it is worth checking whether you need to send a fax at all. The page on Do I Actually Need to Send a Fax? sets out the alternatives some institutions will accept instead.
Common questions about sending a fax from a computer
Do I need to install anything to send a fax from my browser?
No. Online fax services run entirely in a standard browser window, whether that is Chrome, Firefox, Safari or Edge. You upload your document through the website and the service converts it into a fax signal itself, so there is nothing to download or install on your computer.
Is there a limit to how large my file can be?
Most services set some kind of limit, and it tends to be tighter on a free tier than a paid one. Where a service does not state its limit clearly on the upload page, keeping your document to a handful of pages and sending it as a PDF is the safer way to avoid a failed send.
What file formats can I upload?
A signed PDF, meaning a document you have printed, signed, and scanned or exported back to PDF, is accepted almost everywhere and tends to be the most reliable choice, since it keeps your layout and signature exactly as you intended. Many services also accept Word documents and JPEG images, though a photograph of a signed page can come out fainter once it has been converted.
What actually happens to my document once I click send?
The service converts your file into a fax signal and sends it over the telephone network to the recipient's fax number, in much the same way a fax machine would. Once the transmission completes you should get a transmission confirmation, a receipt showing the fax reached the other end, though it does not confirm anyone has read it or that it printed cleanly.
Does it need to be my own computer, or will any computer do?
Any computer with a browser and an internet connection will do. Because you are uploading a document, a work computer, a library computer or a borrowed laptop all work equally well, as long as you have the file and the recipient's fax number to hand.
How do I know the fax actually arrived?
Check for a transmission confirmation, usually shown on screen or emailed to you once the send completes. It tells you the fax reached the number you dialled, but not whether the right person has seen it yet, so it is worth following up by phone or email if the recipient hasn't acknowledged it.