Email signature QR code: when it helps, what to encode and how big to make it

An email signature QR code helps in two situations: the reader has your email open on a computer and wants your details on a phone, or the email gets printed. Everywhere else a plain link does the same job with less risk. The risk is real. In a consumer alert dated 6 December 2023, the US Federal Trade Commission tells people not to scan a QR code in an email or text message they were not expecting.

We read the QR Code standards and generating pages on qrcode.com (run by Denso Wave), Apple’s iPhone User Guide, the FTC alert, the ZXing project’s Barcode Contents wiki (last edited January 2021) and RFC 6350 for the vCard format, all in October 2026. We have not tested codes on a range of phones, so there is no scan-rate figure here, and our own rules are labelled as ours.

When an email signature QR code helps

The answer depends on where the reader is. This table is our judgement.

Situation	Verdict	Reason
Reader on a laptop, wants your details on a phone	Helps a little	The phone’s camera can point at the laptop screen.
Reader on a phone	Noise	A phone cannot easily scan its own screen, and a link is one tap.
Email printed or saved as a PDF	Helps	Nothing can be clicked on paper.
Cold email to a stranger	Hurts	The FTC advises against scanning unexpected codes in email.
Internal email	Noise	Colleagues have the directory.
Long-standing client	Neutral	They already have your number.

Before adding a code, ask whether your readers would scan one that arrived in an email. The FTC’s advice says a careful person will not, so an email signature QR code competes with that advice.

What to encode in an email signature QR code

There are two real choices, and a QR code stores only text, so the question is which text.

A web address. Short, and the reader’s phone shows it before opening it. The ZXing wiki says a reader should probably show the URL and ask whether to proceed. Point it at a contact or booking page on your own domain.

A vCard. The contact details themselves. The wiki says vCard is verbose for 2D barcodes, whose capacity is limited, and also describes a more compact format called MECARD. RFC 6350 defines vCard 4.0 and says a vCard must include VERSION and FN (the formatted name). A minimal card for a vCard QR code signature looks like this, with a made-up person:

• BEGIN:VCARD
• VERSION:3.0
• FN:Maya Chen
• TEL:+14155550142
• EMAIL:maya@harbourstudio.example
• END:VCARD

The wiki’s own sample uses version 3.0, while the RFC is version 4.0. We did not test which versions phones accept from a scan, so test yours.

More text means a bigger code. Denso’s capacity table gives the number of binary characters each version holds at each error correction level. We counted the bytes of three payloads and read the version off the level M column (level M restores about 15 percent of damaged codewords, according to Denso). A version 1 code is 21 by 21 modules, and each version adds 4 per side.

Payload	Bytes	Version at level M	Modules	With 4-module margin	At 3 pixels per module
https://harbourstudio.example/maya	34	3	29	37	111 pixels
The six-line vCard above	101	6	41	49	147 pixels
A vCard with organisation, title and website	194	10	57	65	195 pixels

The bytes assume plain ASCII text with carriage return and line feed between lines.

Size and margin for an email signature QR code

Denso says the larger the module (one small square), the more stable and easy to read the code is. For printing it recommends modules made of four or more printer dots. It also says a QR code needs a clear margin, the quiet zone, four modules wide on every side.

Its troubleshooting page lists what goes wrong: resizing an image with a tool can distort every module, placing letters or pictures around the code removes the margin, and overlaying a logo spoils the contrast. Codes that are decorated may not read. So export the code at a whole number of pixels per module, and make the signature display it at exactly that size, with no stretching.

Now the awkward part. Our column at 3 pixels per module is a rule of thumb for screens, not a tested minimum. A web-address code at 3 pixels per module is 111 pixels square. In a Google admin-set footer, where Google’s page gives 100 pixels high as the maximum image height, only about 2 pixels per module fits (37 times 2 is 74). Whether that scans reliably on small screens, we cannot say.

How to make and test an email signature QR code

1. Choose the target. A short page on your own domain, not a third-party shortener. Our reason: the FTC tells people to inspect the address first, and a shortener hides it.
2. Generate a PNG at a whole number of pixels per module with the four-module margin included. Use level M unless you have a reason to go higher.
3. Set the size in the signature to the file’s real size.
4. Add the alt text and the address as text. For example, the alt text “Scan to save Maya Chen’s contact details”, and beside it harbourstudio.example/maya. Microsoft’s accessibility page asks that text inside an image be repeated in the message.
5. Test with the iPhone Camera. Apple’s page says to open Camera, stay in Photo mode, position the iPhone so the code appears inside the frame, and tap the link that appears at the bottom. A second route is the Scan Code control in Control Center.
6. Test with images off. Classic Outlook does not fetch remote pictures automatically unless the reader changes the setting (Microsoft), so some readers will not see the code at all.

In Gmail the route is Settings > See all settings, then the Signature box and its Insert image button, which offers Upload, My Drive or Web Address (URL) (Google). These steps follow Google’s and Apple’s help pages, read in October 2026.

The safety side of an email signature QR code

The FTC alert says scammers hide harmful links in QR codes, sometimes sending a code by text or email with a made-up reason to scan it. Its advice to readers is to inspect the address before opening it, to avoid scanning codes in unexpected emails or texts, and to keep their phone updated.

Your own code should make that easy. Put the readable address beside it, use your company’s domain, and do not change the target without telling people. Our reasoning, not the FTC’s, is that a code that cannot be checked by eye invites the very hesitation the FTC recommends.

What emailfooter does with an email signature QR code

emailfooter has no QR field, and an employee cannot add one to a signature built there. What it has is a Book a meeting link and a website line, both plain text links that work on any device. In the example below, that link does the job a code would do.

A text link instead of an email signature QR code: Book a meeting. Example only. The company and person are made up.

For a code you must still use your mail app’s own editor. Staff install their emailfooter signature themselves, so any code is added by hand afterward, in the mail app. Our article on the signature versus a digital business card weighs the alternatives, the banner article covers other images, and adding a link covers the plain-text route.

Frequently asked questions

Can you put an email signature QR code in Gmail?

Yes, as an image: Settings > See all settings > Signature > Insert image. The code counts toward Gmail’s 10,000 character signature limit, so keep the file small.

How big should a QR code in email signature blocks be?

Denso asks for larger modules and a four-module margin. A short web address is 29 modules, 37 with the margin, and our rule of thumb is 3 pixels per module, so about 111 pixels. That is untested.

What does a vCard QR code signature contain?

A vCard needs VERSION and FN under RFC 6350. Add TEL and EMAIL if you want, but each line makes the code denser. Test on your own phones.

Is an email signature QR code safe?

The FTC warns that scammers use QR codes, and advises against scanning unexpected ones in email. Use your own domain and print the address as text.

Do QR codes in email signatures work on a phone?

Not well. The phone cannot easily scan its own screen, so the reader would tap a link instead. Keep a text link.