diff --git a/src/extern.h.in b/src/extern.h.in
index f745407..a60be86 100644
--- a/src/extern.h.in
+++ b/src/extern.h.in
@@ -55,6 +55,9 @@
 #define CYAN	36
 #define WHITE	37
 
+/* html color code length (type of #FF0000, etc.) without the # */
+#define HTMLCOLORCODELENGTH 6
+
 struct conf {
 	int chead;	/* color used for the header */
 	int clow;	/* color when usage low */
diff --git a/src/util.c b/src/util.c
index f64e02d..1c8f09e 100644
--- a/src/util.c
+++ b/src/util.c
@@ -872,11 +872,11 @@ chk_html_colorcode(char *color)
 {
 	int i;
 
-	if (strlen(color) != 6)
+	if (strlen(color) != HTMLCOLORCODELENGTH)
 		return -1;
 		/* NOTREACHED */
 
-	for (i = 0; i < 6; i++)
+	for (i = 0; i < HTMLCOLORCODELENGTH; i++)
 		if (isxdigit(color[i]) == 0)
 			return -1;
 			/* NOTREACHED */