Online fax service: how it works and what it costs
An online fax service sends and receives faxes over the internet for you, so you don't need a fax machine or a phone line. You upload a file or scan a page, type the fax number, and the service dials the other side's fax machine; faxes sent to you arrive as PDFs.
The real choice is how you pay: a monthly plan with a page allowance and a fax number, or paying per fax when you need one.
Full disclosure: I make HonestFax, the first option below. The prices of other services are the ones they publish on their own websites.
How an online fax service works
- You give it the pages. A PDF, a photo, or a page scanned with your phone camera. Most services turn everything into one fax document.
- You type the fax number. The service calls that number over the phone network, the same way a fax machine would.
- The other side gets a normal fax. Their machine prints it, or their own fax service shows it as a PDF. They can't tell it didn't come from a machine.
- You get a result. Delivered, or failed with a reason such as a busy line or a number that isn't a fax line. A good service retries a busy line for you - why a fax fails explains the common reasons.
- To receive, you need a fax number. It's a phone number connected to the service. When someone faxes it, the pages arrive as a PDF in an app, a web inbox or your email.
Sending works on almost every service without a fax number. Receiving always needs one, and that's usually what the monthly price pays for.
Online fax services compared
| Option | How you pay | Fax number for receiving |
|---|---|---|
| No subscription needed HonestFax (iPhone app) | First page free, then pay per fax: up to 3 pages $2.99, 10 pages $4.99, 30 pages $9.99 - pages never expire | 7-Day Pass $9.99, does not renew; or Pro $12.99 a month / $79.99 a year |
| Fax.Plus | Free plan: 10 pages in total. Basic: $8.99 a month, or $83.99 a year ($6.99 a month), 200 pages a month, $0.10 per extra page | One number on Basic |
| eFax | Personal: $18.99 a month, or $189.96 a year ($15.83 a month), 200 pages a month to the US and Canada, $0.10 per extra page | One number on Personal |
Monthly plans renew until you cancel. That's fine if you fax every week, and an expensive surprise if you needed one fax in March.
Sending with HonestFax
HonestFax is an online fax service you use from your iPhone. There's no website and no email to fax - you send from the app:
- Install HonestFax and open the New Fax tab. No account to fill in.
- Add the pages. Scan paper with the camera, pick photos, or attach a PDF from Files. If the file is on your computer, how to fax from a computer shows how to move it to your phone in a few seconds.
- Type the fax number. Sending works to the US, Canada, the UK, Germany and Japan.
- Check the page count and the price above the Send fax button, then send.
- Watch it go through. You see each step until it says Delivered. If it can't be delivered, the credits come back automatically.
The full walkthrough, with screenshots, is in how to send a fax from your iPhone.
Receiving with an online fax service
To receive, you need your own fax number. In HonestFax there are two ways, and both give you a personal US or Canadian number:
- Once: the 7-Day Pass gives you a number for 7 days and up to 100 pages of sending, for $9.99. It never renews.
- Regularly: HonestFax Pro keeps the number for as long as you're subscribed, with unlimited sending.
Incoming faxes land in the app's Inbox as PDFs, and you can share, save or print them. How it works step by step: how to receive a fax on iPhone. If you're comparing number options in general, see how to get a fax number.
How to choose an online fax service
- How often do you fax? A few times a year: pay per fax. Every week: a monthly plan can be cheaper per page.
- Do you need to receive? If someone has to fax you, you need a number - check that the plan includes one, and for how long.
- Where do you send from? From a desk, a web app or email to fax is handy - can you send a fax by email covers how that works. From your phone, an app with a scanner saves a step.
- What happens if a fax fails? Look for automatic retries and whether failed pages are charged.
- How do you stop paying? A subscription bought in the App Store is cancelled in your iPhone's settings - see how to cancel a fax app subscription on iPhone.
For a full price comparison, including print shops and free fax websites, see how much does it cost to send a fax.
Frequently asked questions
Is there a free online fax service? For sending a few pages, yes. Free plans and free fax websites send short faxes, usually with page limits. Receiving almost always needs a paid plan, because a fax number costs money. In HonestFax your first page is free on a new device.
Do I need a phone line for an online fax service? No. The service has the phone lines; you only need an internet connection.
Can an online fax service receive faxes? Yes, if you have a fax number with it. The pages arrive as PDFs in the app, a web inbox or your email, depending on the service.
Is an online fax as valid as a fax from a machine? The receiving machine gets the same fax signal either way, so the office on the other side sees a normal fax. Whether they accept faxes for your document is up to them.
Checked on October 24, 2026: Fax.Plus plans, monthly and annual prices, page allowances and the free plan's 10 pages on its pricing page (fax.plus/pricing). eFax Personal plan price, pages and per-page overage on its pricing page (efax.com/pricing). HonestFax prices and pass terms as shown in the app and on the HonestFax pricing section.