diff -r e168590166a5 sys/src/cmd/ip/httpd/httpd.c
--- a/sys/src/cmd/ip/httpd/httpd.c	Sun Jul 19 14:14:14 2020 -0700
+++ b/sys/src/cmd/ip/httpd/httpd.c	Sun Jul 19 14:18:57 2020 -0700
@@ -51,6 +51,7 @@
 	address = nil;
 	hmydomain = nil;
 	netdir = "/net";
+	tmfmtinstall();
 	fmtinstall('D', hdatefmt);
 	fmtinstall('H', httpfmt);
 	fmtinstall('U', hurlfmt);
diff -r e168590166a5 sys/src/libhttpd/date.c
--- a/sys/src/libhttpd/date.c	Sun Jul 19 14:14:14 2020 -0700
+++ b/sys/src/libhttpd/date.c	Sun Jul 19 14:18:57 2020 -0700
@@ -4,212 +4,41 @@
 
 /*
  * print dates in the format
- * Wkd, DD Mon YYYY HH:MM:SS GMT
+ * Wkd, DD Mon YYYY HH:MM:SS +0000
+ */
+int
+hdatefmt(Fmt *f)
+{
+	Tm *tm, ts;
+	ulong t;
+
+	t = va_arg(f->args, ulong);
+	tm = tmtime(&ts, t, nil);
+	return fmtprint(f, "%τ", tmfmt(tm, "WW DD MMM YYYY hh:mm:ss Z"));
+}
+
+/*
  * parse dates of formats
  * Wkd, DD Mon YYYY HH:MM:SS GMT
  * Weekday, DD-Mon-YY HH:MM:SS GMT
  * Wkd Mon ( D|DD) HH:MM:SS YYYY
  * plus anything similar
- */
-static char *
-weekdayname[7] =
-{
-	"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"
-};
-static char *
-wdayname[7] =
-{
-	"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
-};
-
-static char *
-monname[12] =
-{
-	"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
-};
-
-static	int	dateindex(char*, char**, int);
-
-static int
-dtolower(int c)
-{
-	if(c >= 'A' && c <= 'Z')
-		return c - 'A' + 'a';
-	return c;
-}
-
-static int
-disalpha(int c)
-{
-	return c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z';
-}
-
-static int
-disdig(int c)
-{
-	return c >= '0' && c <= '9';
-}
-
-int
-hdatefmt(Fmt *f)
-{
-	Tm *tm;
-	ulong t;
-
-	t = va_arg(f->args, ulong);
-	tm = gmtime(t);
-	return fmtprint(f, "%s, %.2d %s %.4d %.2d:%.2d:%.2d GMT",
-		wdayname[tm->wday], tm->mday, monname[tm->mon], tm->year+1900,
-		tm->hour, tm->min, tm->sec);
-}
-
-static char*
-dateword(char *date, char *buf)
-{
-	char *p;
-	int c;
-
-	p = buf;
-	while(!disalpha(c = *date) && !disdig(c) && c)
-		date++;
-	while(disalpha(c = *date)){
-		if(p - buf < 30)
-			*p++ = dtolower(c);
-		date++;
-	}
-	*p = 0;
-	return date;
-}
-
-static int
-datenum(char **d)
-{
-	char *date;
-	int c, n;
-
-	date = *d;
-	while(!disdig(c = *date) && c)
-		date++;
-	if(c == 0){
-		*d = date;
-		return -1;
-	}
-	n = 0;
-	while(disdig(c = *date)){
-		n = n * 10 + c - '0';
-		date++;
-	}
-	*d = date;
-	return n;
-}
-
-/*
- * parse a date and return the seconds since the epoch
- * return 0 for a failure
+ * return seconds from epoch, 0 for a failure
  */
 ulong
 hdate2sec(char *date)
 {
+	char **f, *fmt[] = {
+		"?W, ?DD ?MM ?YYYY hh:mm:ss ?Z",
+		"?W, ?DD-?MM-?YYYY-hh:mm:ss ?Z",
+		"?W, ?DD ?MM ?YYYY hh:mm:ss",
+		"?W, ?DD-?MM-?YYYY hh:mm:ss",
+		nil,
+	};
 	Tm tm;
-	char buf[32];
 
-	memset(&tm, 0, sizeof(tm));
-
-	/*
-	 * Weekday|Wday
-	 */
-	date = dateword(date, buf);
-	tm.wday = dateindex(buf, wdayname, 7);
-	if(tm.wday < 0)
-		tm.wday = dateindex(buf, weekdayname, 7);
-	if(tm.wday < 0)
-		return 0;
-
-	/*
-	 * check for the two major formats
-	 */
-	date = dateword(date, buf);
-	tm.mon = dateindex(buf, monname, 12);
-	if(tm.mon >= 0){
-		/*
-		 * MM
-		 */
-		tm.mday = datenum(&date);
-		if(tm.mday < 1 || tm.mday > 31)
-			return 0;
-
-		/*
-		 * HH:MM:SS
-		 */
-		tm.hour = datenum(&date);
-		if(tm.hour < 0 || tm.hour >= 24)
-			return 0;
-		tm.min = datenum(&date);
-		if(tm.min < 0 || tm.min >= 60)
-			return 0;
-		tm.sec = datenum(&date);
-		if(tm.sec < 0 || tm.sec >= 60)
-			return 0;
-
-		/*
-		 * YYYY
-		 */
-		tm.year = datenum(&date);
-		if(tm.year < 70 || tm.year > 99 && tm.year < 1970)
-			return 0;
-		if(tm.year >= 1970)
-			tm.year -= 1900;
-	}else{
-		/*
-		 * MM-Mon-(YY|YYYY)
-		 */
-		tm.mday = datenum(&date);
-		if(tm.mday < 1 || tm.mday > 31)
-			return 0;
-		date = dateword(date, buf);
-		tm.mon = dateindex(buf, monname, 12);
-		if(tm.mon < 0 || tm.mon >= 12)
-			return 0;
-		tm.year = datenum(&date);
-		if(tm.year < 70 || tm.year > 99 && tm.year < 1970)
-			return 0;
-		if(tm.year >= 1970)
-			tm.year -= 1900;
-
-		/*
-		 * HH:MM:SS
-		 */
-		tm.hour = datenum(&date);
-		if(tm.hour < 0 || tm.hour >= 24)
-			return 0;
-		tm.min = datenum(&date);
-		if(tm.min < 0 || tm.min >= 60)
-			return 0;
-		tm.sec = datenum(&date);
-		if(tm.sec < 0 || tm.sec >= 60)
-			return 0;
-
-		/*
-		 * timezone
-		 */
-		dateword(date, buf);
-		if(strncmp(buf, "gmt", 3) != 0)
-			return 0;
-	}
-
-	strcpy(tm.zone, "GMT");
-	tm.tzoff = 0;
-	tm.yday = 0;
-	return tm2sec(&tm);
-}
-
-static int
-dateindex(char *d, char **tab, int n)
-{
-	int i;
-
-	for(i = 0; i < n; i++)
-		if(cistrcmp(d, tab[i]) == 0)
-			return i;
+	for(f = fmt; *f != nil; f++)
+		if(tmparse(&tm, *f, date, nil, nil) != nil)
+			return tmnorm(&tm);
 	return -1;
 }