diff --git a/api/storage.go b/api/storage.go
index c859a7b9..4d306b0b 100644
--- a/api/storage.go
+++ b/api/storage.go
@@ -7,19 +7,24 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
+type diskFree struct {
+	// Storage size [MiB]
+	Total uint64
+	// Available Storage [MiB]
+	Free uint64
+	// Percentage Full
+	PercentFull float32
+}
+
 // @Summary Get Storage Utilization
-// @Description Get disk free information of aptly storage
+// @Description **Get disk free information of aptly storage**
 // @Tags Status
 // @Produce json
-// @Success 200 {object} string "usage information"
+// @Success 200 {object} diskFree "Storage information"
 // @Failure 400 {object} Error "Internal Error"
 // @Router /api/storage [get]
 func apiDiskFree(c *gin.Context) {
-	var df struct {
-		Total       uint64
-		Free        uint64
-		PercentUsed float32
-	}
+	var df diskFree
 
 	fs := context.Config().GetRootDir()
 
@@ -32,7 +37,7 @@ func apiDiskFree(c *gin.Context) {
 
 	df.Total = uint64(stat.Blocks) * uint64(stat.Bsize) / 1048576
 	df.Free = uint64(stat.Bavail) * uint64(stat.Bsize) / 1048576
-	df.PercentUsed = 100.0 - float32(stat.Bavail)/float32(stat.Blocks)*100.0
+	df.PercentFull = 100.0 - float32(stat.Bavail)/float32(stat.Blocks)*100.0
 
 	c.JSON(200, df)
 }