diff --git a/gauge.go b/gauge.go
index 4b93da1..ff2bda5 100644
--- a/gauge.go
+++ b/gauge.go
@@ -37,7 +37,7 @@ func (g *Gauge) Get() float64 {
 func (g *Gauge) marshalTo(prefix string, w io.Writer) {
 	v := g.f()
 	if float64(int64(v)) == v {
-		// Marshal integer values without scientific notations
+		// Marshal integer values without scientific notation
 		fmt.Fprintf(w, "%s %d\n", prefix, int64(v))
 	} else {
 		fmt.Fprintf(w, "%s %g\n", prefix, v)
diff --git a/summary.go b/summary.go
index def1f4e..509ce4a 100644
--- a/summary.go
+++ b/summary.go
@@ -109,7 +109,12 @@ func (sm *Summary) marshalTo(prefix string, w io.Writer) {
 
 	if count > 0 {
 		name, filters := splitMetricName(prefix)
-		fmt.Fprintf(w, "%s_sum%s %g\n", name, filters, sum)
+		if float64(int64(sum)) == sum {
+			// Marshal integer sum without scientific notation
+			fmt.Fprintf(w, "%s_sum%s %d\n", name, filters, int64(sum))
+		} else {
+			fmt.Fprintf(w, "%s_sum%s %g\n", name, filters, sum)
+		}
 		fmt.Fprintf(w, "%s_count%s %d\n", name, filters, count)
 	}
 }