Can I fax from a scanner without a phone line?

Yes. Scan your document to a PDF file, then upload it to an online fax service like [mFax.to](https://mfax.to). No phone line, no fax modem, and no dedicated fax machine required — just a scanner and an internet connection.

What DPI should I use when scanning for fax?

200–300 DPI is the sweet spot. Fine fax resolution is 204×196 DPI, so scanning at 200–300 DPI captures all the detail a fax needs. Higher DPI (600+) only creates a larger file without improving the received fax quality. See our full [fax resolution settings guide](/blog/fax-resolution-settings/).

What file format should I save a scan for faxing?

PDF is the best choice. It supports multi-page documents in a single file, preserves formatting, and is accepted by every online fax service. Avoid JPG — compression artifacts reduce text clarity.

Do I need a special scanner to send a fax?

No. Any flatbed, sheet-fed, or all-in-one scanner works for the scan-then- send-online method. Only the direct fax method (via phone line) requires a multifunction printer with a built-in fax modem and an RJ-11 phone port.

Why is my fax coming out blurry after scanning?

The two most common causes are scanning in color or grayscale (switch to black-and-white monochrome) and scanning at too low a DPI. A dirty scanner glass also causes streaks and soft spots. See our [blurry fax troubleshooting guide](/blog/why-is-my-fax-blurry/) for a full checklist.

How to Fax From Scanner: Step-by-Step Guide (2026)

You can fax from a scanner two ways: directly via a built-in fax modem on an all-in-one printer, or by scanning to PDF and uploading to an online fax service — no phone line required. This guide covers both methods step by step for HP, Brother, Canon, and Epson.

By Sarah Martinez · Published March 28, 2026 · Updated June 8, 2026 · 8 min read

Faxing from a scanner is simpler than most people expect — and you have two solid paths to choose from depending on your setup.

Method 1 (Direct fax): If you own an all-in-one printer with a built-in fax modem and a working phone line, you can fax directly from the control panel without any software.

Method 2 (Scan then fax online): If you have any scanner — standalone, built into a printer, or even your phone — you can scan the document to a PDF and send it via an online fax service like mFax.to. No phone line, no fax modem, no problem.

Method 2 is faster, more reliable, and works anywhere. This guide covers both, starting with Method 2 since that is what most people actually need.

Which Method Is Right for You?

Factor	Direct Fax (Built-in Modem)	Scan then Fax Online
Phone line required	Yes — RJ-11 physical line	No
Works on any scanner	No — MFP with fax port only	Yes
Internet required	No	Yes
Delivery confirmation	Activity report printed	Email/push notification
Receive faxes	Auto-answer (print to paper)	Cloud inbox, email forward
Setup time	15–30 minutes	Under 2 minutes
Ongoing cost	Phone line ~$30–40/mo	Subscription ~$5–21/mo
Works on VoIP lines	Unreliable	Yes, fully

Most Scanners Can't Fax Directly

Only all-in-one printers with a dedicated RJ-11 fax port can send faxes directly. Standalone flatbed scanners (Brother PDS, Fujitsu fi series, Canon CanoScan) have no fax capability on their own — you must use the scan-then-fax-online method.

Method 1: Scan then Fax Online (Recommended)

This method works with any scanner and requires no phone line. Scan your document to a PDF, then upload it to an online fax service.

Best Scan Settings for Faxing

Before you scan, configure your scanner software with these settings:

Setting	Recommended Value	Why
Resolution (DPI)	200–300 DPI	Fine fax quality is 204×196 DPI — higher DPI creates larger files with no benefit
Color mode	Black & White (monochrome)	Fax machines receive and print in B&W only; color scans create larger, unnecessary files
File format	PDF	Single multi-page file, universally accepted, no compression artifacts
Contrast	High	Text should be crisp black on pure white — no gray haze

Avoid Color and Grayscale Scans

Scanning in color or grayscale is one of the most common reasons faxes look blurry or faded on the receiving end. Always choose Black & White (monochrome) for fax documents. See our blurry fax guide if you are still getting poor quality.

Step-by-Step: Scan to PDF and Send via mFax.to

Place Your Document

Place your document face-down on the flatbed glass (or face-up in the ADF tray for multi-page documents). For multi-page sets, fan the pages before inserting them in the ADF to prevent jams.

Open Your Scanner Software

Open your scanner software — Windows Fax and Scan, HP Smart, Image Capture (Mac), or the printer's own application. Select Black & White, set resolution to 200–300 DPI, and choose PDF as the output format.

Scan and Save

Click Scan. Save the file to your desktop or a known folder. For multi-page documents, make sure all pages are combined into one PDF — most scanner apps do this automatically when using the ADF.

Open mFax.to

Visit mFax.to or open the mFax app on your phone. Log in or create a free account.

Upload Your Scanned PDF

Click New Fax or Send Fax. Drag and drop your scanned PDF (or use the file picker). mFax.to accepts PDF, TIFF, DOC, and most common document formats.

Enter the Recipient Fax Number

Type the recipient's fax number. For US numbers, include the area code. For international faxes, add the country code (e.g., +44 for UK). See our international faxing guide for country-specific formatting.

Add a Cover Page (Optional)

Add a cover sheet if needed — useful for professional or medical documents. mFax.to has built-in cover page templates, or use the free cover sheet generator to make a custom one first.

Send and Confirm

Click Send. You will receive a delivery confirmation notification with a timestamp, page count, and success or failure status. No guessing — you know exactly when your fax arrived.

Why mFax.to Over Other Services

mFax.to delivers faxes with a 98% success rate, is used by over 5 million people, and carries a 4.8-star App Store rating. No fax machine. No phone line. Send in under 2 minutes.

Method 2: Fax Directly from an All-in-One Printer

If your printer has a built-in fax modem and you have a working analog phone line, you can fax directly from the control panel.

Requirement: Physical Phone Line

The built-in fax function requires an analog RJ-11 phone line connected to the port labeled LINE on the back of the printer. VoIP and digital lines (Comcast, Spectrum, AT&T Fiber) are often incompatible with analog fax signals. If your fax fails with a "Comm Error" or "No Dial Tone," your line is likely digital — use the online method above instead. For background, see our guide on why fax needs a phone line.

HP All-in-One Printers

Phone-line setup (one-time):

Find the port labeled 1-LINE on the back of the printer.
Plug one end of the phone cable into 1-LINE and the other into the wall jack.
On the control panel: go to Setup → Fax Setup → Basic Fax Setup and configure your fax header (name and number).

Sending a fax from the control panel:

Load document face-down on the glass or face-up in the ADF.
Press Fax on the control panel.
Enter the recipient's fax number using the keypad.
Press Start (or Send).

HP Smart App (no phone line needed): HP's mobile app includes a Mobile Fax feature that routes faxes through HP's cloud — no phone line required. Open the HP Smart app → tap Fax → scan or upload → enter the number → send. Status appears under the Sent tab and can be cancelled within ~30 seconds.

Brother MFC Series

Load document face-up in the ADF (or face-down on the flatbed for single pages).
Fan pages before loading into the ADF.
Press the FAX button on the control panel.
Dial the recipient's fax number on the keypad.
Press Start.

Fax-capable Brother models include the MFC-J4335DW ($159.99), MFC-L2820DW ($249.99, monochrome laser), and MFC-J4540DW ($529.69). See our full printer fax guide for the complete Brother setup walkthrough.

Epson WorkForce / EcoTank Series

One-time setup via Fax Setting Wizard:

On the touchscreen: Settings → General Settings → Fax Settings → Fax Setting Wizard.
Enter your sender name and fax number.
Connect the phone cable to the RJ-11 port on the printer.

Sending:

Load document in the ADF or on the flatbed.
Select Fax from the home screen.
Enter the fax number (or select from speed-dial).
Adjust resolution under Fax Send Settings if needed.
Tap Send.

Fax-capable Epson models include the WorkForce WF-2950 and EcoTank ET-4850 (25 ppm, 4.3" touchscreen, $849.99).

Canon PIXMA / imageCLASS Series

Load document face-down on the glass or face-up in the ADF.
Press the FAX button on the control panel.
Dial the recipient's fax number using the numeric pad.
Press Black for B&W transmission (or Color for color, though B&W is standard).
The printer scans and transmits automatically.

Fax-capable Canon models include the PIXMA MX490/MX922 (inkjet) and imageCLASS MF462dw ($366, 37 ppm laser).

Faxing from a Scanner on Windows

Windows Fax and Scan is a built-in Windows utility that can scan documents. The fax-sending portion requires a hardware fax modem — most modern computers do not have one.

Practical workflow (any Windows version):

Open Windows Fax and Scan (search in the Start menu).
Click File → New → Scan.
Select your scanner, set resolution to 200–300 DPI, color mode to Black & White, and format to PDF or TIFF.
Click Scan. The document appears in the Windows Fax and Scan inbox.
Right-click the scan → Save As to save it as a PDF.
Upload the saved PDF to mFax.to or another online fax service and send.

For a complete Windows-specific walkthrough including multi-page scanning, see our guide to Windows Fax and Scan.

Faxing from a Scanner on Mac

macOS removed its native fax modem support in older versions. The modern approach:

Open System Settings → Printers & Scanners → select your printer/scanner → click Open Scanner.
Set Color to Black & White, Resolution to 200–300 DPI, Format to PDF.
Click Scan and save the file.
Upload the PDF to mFax.to and send.

Alternatively, open Image Capture directly from the Applications folder for more control over scan settings. For a full Mac faxing guide, see how to fax on Mac.

Troubleshooting Common Problems

Fax says "No Dial Tone" or won't connect

Cause: The phone cable is in the wrong port, or the phone line is digital (VoIP).

Fix:

Move the cable from the EXT port to the LINE port on the back of the printer.
Test the wall jack with a regular phone to confirm you have an analog dial tone.
If on VoIP/fiber, switch to the online fax method — analog fax over VoIP is unreliable by design.

Fax comes out blurry or faded

Cause: Color scanning, low DPI, or dirty scanner glass.

Fix:

Switch color mode to Black & White (monochrome).
Increase DPI to 200–300.
Clean the scanner glass with a lint-free cloth.
Check our full blurry fax troubleshooting guide for a complete checklist.

Recipient gets blank pages

Cause: Document placed on the wrong side.

Fix:

Flatbed glass: document must be face-down.
ADF tray: document must be face-up.

Fax fails to send / "Comm Error"

Cause: Phone line noise (common with VoIP/DSL), busy recipient, or wrong number format.

Fix:

Include the area code and country code for international destinations.
Online fax services like mFax.to retry automatically — no manual redial needed.
If on VoIP, use the online fax method or configure your VoIP adapter for T.38 protocol at 9,600 bps or lower.

Scanner not detected by software

Cause: Driver not installed or USB not connected.

Fix:

Download the latest scanner driver from the manufacturer's website.
Reconnect the USB cable and restart the print spooler (Windows: services.msc → Print Spooler → Restart).
In Windows Fax and Scan, uncheck Auto Crop if it is interfering with ADF scans.

Frequently Asked Questions

The FAQs below are also embedded in the page schema for Google rich results.

Can I fax from a scanner without a fax machine? Yes — scan the document to a PDF and send it via an online fax service. No fax machine, no phone line required.

Does fax quality degrade when sent from a scanned PDF? No, provided you scan at 200–300 DPI in black-and-white. The resulting fax quality matches or exceeds what a traditional fax machine produces.

Are online faxes from scanned documents legally valid? Yes. Faxes sent via online services carry the same legal weight as traditional faxes. Courts, hospitals, banks, the IRS, and government agencies all accept them.

How long does it take to fax a scanned document? With an online service like mFax.to, delivery typically completes within seconds to a few minutes. Traditional phone-line fax transmits at approximately one page per minute at Fine quality.

The Bottom Line

The fastest and most reliable way to fax from a scanner in 2026 is to scan to PDF and send via an online fax service. It works with any scanner, requires no phone line, and gives you delivery confirmation the moment your fax arrives.

For occasional faxing — a tax form, a medical record, a signed contract — mFax.to is the simplest option. Open the app or website, upload your scanned PDF, enter the fax number, and send. Most faxes are delivered in under two minutes, with over 5 million users and a 98% delivery success rate.

For business teams that send and receive faxes regularly, mFax Business adds a dedicated virtual fax number, HIPAA compliance features, team accounts, and a shared dashboard — starting at about $9/mo (billed annually). Rather than rigid fixed tiers, you build your own plan with a live calculator: pick the exact seats and pages you need and pay only for what you use.

No machine. No phone line. No waiting.