diff --git a/congestion/rtt_stats.go b/congestion/rtt_stats.go
index d5a67d9af..e538c8b6d 100644
--- a/congestion/rtt_stats.go
+++ b/congestion/rtt_stats.go
@@ -85,7 +85,7 @@ func (r *RTTStats) SetRecentMinRTTwindow(recentMinRTTwindow time.Duration) {
 // UpdateRTT updates the RTT based on a new sample.
 func (r *RTTStats) UpdateRTT(sendDelta, ackDelay time.Duration, now time.Time) {
 	if sendDelta == math.MaxInt64 || sendDelta <= 0 {
-		fmt.Printf("Ignoring measured sendDelta, because it's is either infinite, zero, or negative: %d", sendDelta/time.Microsecond)
+		fmt.Printf("Ignoring measured sendDelta, because it's is either infinite, zero, or negative: %d\n", sendDelta/time.Microsecond)
 		return
 	}