diff --git a/bar.go b/bar.go
index d07dc16..35644a4 100644
--- a/bar.go
+++ b/bar.go
@@ -165,12 +165,12 @@
 }
 
 // SetTotal sets total dynamically.
-// If total is less than or equal to zero it takes progress' current value.
+// If total is negative it takes progress' current value.
 func (b *Bar) SetTotal(total int64, triggerComplete bool) {
 	select {
 	case b.operateState <- func(s *bState) {
 		s.triggerComplete = triggerComplete
-		if total <= 0 {
+		if total < 0 {
 			s.total = s.current
 		} else {
 			s.total = total
diff --git a/proxyreader.go b/proxyreader.go
index 2f20053..a16f5ec 100644
--- a/proxyreader.go
+++ b/proxyreader.go
@@ -15,7 +15,7 @@
 	n, err := x.ReadCloser.Read(p)
 	x.bar.IncrBy(n)
 	if err == io.EOF {
-		go x.bar.SetTotal(0, true)
+		go x.bar.SetTotal(-1, true)
 	}
 	return n, err
 }
@@ -30,7 +30,7 @@
 	n, err := x.wt.WriteTo(w)
 	x.bar.IncrInt64(n)
 	if err == io.EOF {
-		go x.bar.SetTotal(0, true)
+		go x.bar.SetTotal(-1, true)
 	}
 	return n, err
 }