diff --git a/main.go b/main.go
index 491638c..6002b15 100644
--- a/main.go
+++ b/main.go
@@ -559,6 +559,9 @@ func humanizeDurationSeconds(seconds float64) string {
 	for n := duration / unit; n >= unit; n /= unit {
 		div *= unit
 		exp++
+		if exp >= len(units)-1 {
+			break
+		}
 	}
 
 	return fmt.Sprintf("%.2f%s",
diff --git a/main_test.go b/main_test.go
index 4da3c92..ab75e67 100644
--- a/main_test.go
+++ b/main_test.go
@@ -43,3 +43,20 @@ func TestHeadersParsing(t *testing.T) {
 		}
 	}
 }
+
+func TestHumanizeDurationSeconds(t *testing.T) {
+	requestTime := humanizeDurationSeconds(6000)
+	if requestTime != "6000.00s" {
+		t.Errorf("Wrong requestTime: %q", requestTime)
+	}
+
+	requestTime = humanizeDurationSeconds(0.05)
+	if requestTime != "50.00ms" {
+		t.Errorf("Wrong requestTime: %q", requestTime)
+	}
+
+	requestTime = humanizeDurationSeconds(99999999)
+	if requestTime != "99999999.00s" {
+		t.Errorf("Wrong requestTime: %q", requestTime)
+	}
+}