diff --git a/whisper/whisperv6/envelope.go b/whisper/whisperv6/envelope.go
index 304608fdeb..9ed712b934 100644
--- a/whisper/whisperv6/envelope.go
+++ b/whisper/whisperv6/envelope.go
@@ -51,7 +51,6 @@ type Envelope struct {
 
 // size returns the size of envelope as it is sent (i.e. public fields only)
 func (e *Envelope) size() int {
-	const EnvelopeHeaderLength = 20
 	return EnvelopeHeaderLength + len(e.Data)
 }