Quoted-Printable Encoder Decoder

Quoted-Printable (QP) is a Content-Transfer-Encoding scheme defined in RFC 2045 (part of the MIME specification). It encodes binary data into ASCII text using =XX notation, where XX is the hexadecimal value of the encoded byte.

QP is designed for text content that is mostly ASCII but contains occasional non-ASCII characters. Unlike Base64, QP preserves readable ASCII text, making it ideal for email messages with special characters like accents or symbols.

QP Encoding Rules

• ASCII printable characters (33-126 except =) are sent as-is
• The = character is encoded as =3D
• Non-printable characters (0-31, 127+) are encoded as =XX
• Tab (09) and space (32) are allowed as-is, except at line end
• Lines are limited to 76 characters (soft breaks use = at line end)
• In header mode (RFC 2047), spaces become underscores (_)

1. Encode to QP — Type or paste text into the left panel, then click Encode to convert it to Quoted-Printable format.
2. Decode from QP — Type or paste QP-encoded text into the right panel, then click Decode to convert it back to readable text.
3. Header mode — Enable Header mode for RFC 2047 compliance (spaces become underscores, stricter encoding).
4. Swap & Clear — Click Swap to exchange encode/decode values, Clear All to reset everything.

• Email development — Encode email content with international characters for proper MIME transmission.
• Email header encoding — Encode non-ASCII characters in Subject, From, and To headers using RFC 2047 Q-encoding.
• Debugging email issues — Decode raw email source to inspect and troubleshoot QP-encoded content.
• Data migration — Convert legacy text data that may contain QP-encoded content to plain text.
• API development — Handle QP-encoded text in webhook payloads or email processing pipelines.