diff --git a/metrics/cloudwatch/cloudwatch.go b/metrics/cloudwatch/cloudwatch.go
index 3d664d7..4322d4c 100644
--- a/metrics/cloudwatch/cloudwatch.go
+++ b/metrics/cloudwatch/cloudwatch.go
@@ -196,7 +196,7 @@
 		for _, perc := range cw.percentiles {
 			value := histogram.Quantile(perc)
 			datums = append(datums, &cloudwatch.MetricDatum{
-				MetricName: aws.String(fmt.Sprintf("%s_p%s", name, formatPerc(perc))),
+				MetricName: aws.String(fmt.Sprintf("%s_%s", name, formatPerc(perc))),
 				Dimensions: makeDimensions(lvs...),
 				Value:      aws.Float64(value),
 				Timestamp:  aws.Time(now),
diff --git a/metrics/cloudwatch/cloudwatch_test.go b/metrics/cloudwatch/cloudwatch_test.go
index c56201d..e5442cb 100644
--- a/metrics/cloudwatch/cloudwatch_test.go
+++ b/metrics/cloudwatch/cloudwatch_test.go
@@ -161,10 +161,10 @@
 	svc := newMockCloudWatch()
 	cw := New(namespace, svc, WithLogger(log.NewNopLogger()))
 	histogram := cw.NewHistogram(name).With(label, value)
-	n50 := fmt.Sprintf("%s_p50", name)
-	n90 := fmt.Sprintf("%s_p90", name)
-	n95 := fmt.Sprintf("%s_p95", name)
-	n99 := fmt.Sprintf("%s_p99", name)
+	n50 := fmt.Sprintf("%s_50", name)
+	n90 := fmt.Sprintf("%s_90", name)
+	n95 := fmt.Sprintf("%s_95", name)
+	n99 := fmt.Sprintf("%s_99", name)
 	quantiles := func() (p50, p90, p95, p99 float64) {
 		err := cw.Send()
 		if err != nil {