diff --git a/accounts/abi/error.go b/accounts/abi/error.go
index 51e9864d45..96fc2d8f00 100644
--- a/accounts/abi/error.go
+++ b/accounts/abi/error.go
@@ -84,7 +84,7 @@ func (e Error) String() string {
 
 func (e *Error) Unpack(data []byte) (interface{}, error) {
 	if len(data) < 4 {
-		return "", errors.New("invalid data for unpacking, length is less than 4")
+		return "", fmt.Errorf("invalid data length for unpacking: got %v, want 4", len(data))
 	}
 	if !bytes.Equal(data[:4], e.ID[:4]) {
 		return "", errors.New("invalid data for unpacking, first four bytes are not equal with error's signature")