diff --git a/cmd/promtool/main.go b/cmd/promtool/main.go
index 4dc6c7615f..b9fe787214 100644
--- a/cmd/promtool/main.go
+++ b/cmd/promtool/main.go
@@ -173,7 +173,7 @@ func main() {
 	agentMode := checkConfigCmd.Flag("agent", "Check config file for Prometheus in Agent mode.").Bool()
 
 	queryCmd := app.Command("query", "Run query against a Prometheus server.")
-	queryCmdFmt := queryCmd.Flag("format", "Output format of the query.").Short('o').Default("promql").Enum("promql", "json")
+	queryCmdFmt := queryCmd.Flag("format", "Output format of the query (promql (default) or json).").Short('o').Default("promql").Enum("promql", "json")
 	queryCmd.Flag("http.config.file", httpConfigFileDescription).PlaceHolder("<filename>").ExistingFileVar(&httpConfigFilePath)
 
 	queryInstantCmd := queryCmd.Command("instant", "Run instant query.")