diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -4240,19 +4240,19 @@
 			uint32_t val, frac;
 
 			val = USEC_2_TICKS(tp->t_rttvar);
-			frac = tp->t_srtt % (HPTS_USEC_IN_SEC / hz);
+			frac = tp->t_rttvar % (HPTS_USEC_IN_SEC / hz);
 			tp->t_rttvar = val <<  TCP_RTTVAR_SHIFT;
 			/*
 			 * frac is the fractional part here is left
 			 * over from converting to hz and shifting.
-			 * We need to convert this to the 5 bit
+			 * We need to convert this to the 4 bit
 			 * remainder.
 			 */
 			if (frac) {
 				if (hz == 1000) {
-					frac = (((uint64_t)frac *  (uint64_t)TCP_RTT_SCALE) / (uint64_t)HPTS_USEC_IN_MSEC);
+					frac = (((uint64_t)frac *  (uint64_t)TCP_RTTVAR_SCALE) / (uint64_t)HPTS_USEC_IN_MSEC);
 				} else {
-					frac = (((uint64_t)frac * (uint64_t)(hz) * (uint64_t)TCP_RTT_SCALE) /(uint64_t)HPTS_USEC_IN_SEC);
+					frac = (((uint64_t)frac * (uint64_t)(hz) * (uint64_t)TCP_RTTVAR_SCALE) /(uint64_t)HPTS_USEC_IN_SEC);
 				}
 				tp->t_rttvar += frac;
 			}