Email QR Code
A QR code that opens a new email with the address, subject and body filled in.
To
Subject
Body
How this processes your file
The address, subject and body are assembled into a mailto: URI with the subject and body percent-encoded, which is what makes punctuation and line breaks survive intact — the failure mode without it is a body that stops at the first ampersand. Scanning opens a new message with everything filled in and nothing sent; every mail client requires that final confirmation. The practical constraint is length: a long body makes the code dense, and a dense code printed small is the main reason QR codes fail to scan in the real world.
What the results mean
- mailto:
- The URI scheme for composing a message. Universally supported.
- Percent-encoding
- What lets punctuation, ampersands and line breaks survive in the subject and body.
- Density
- Long bodies make dense codes. Dense codes printed small are the usual scanning failure.
- Sent automatically
- Never. The mail client opens with the message ready.
Common problems and fixes
- The body is cut short
- Unencoded special characters, usually an ampersand, ending the parameter early. This tool encodes them, so a truncated body means the code was built elsewhere.
- It opens the wrong mail app
- The person's default client, which is a device setting and not something a code can override.
- The code will not scan from my poster
- Too dense for the printed size. Shorten the body or print larger — density is reported above for exactly this reason.
Frequently asked questions
Can a QR code send an email automatically?
No. It can only open a composer with fields filled in. Sending always requires the person to act, which is why a mailto code cannot be abused to send mail in someone's name.
Why does my body text get truncated elsewhere?
Unencoded characters. An ampersand in an unencoded body ends the parameter, so everything after it is lost. Proper percent-encoding fixes it.
How long can the body be?
Technically thousands of characters, practically much less — the code gets denser with every character and a dense code printed small does not scan reliably.