diff --git a/docs/cmdline-opts/cert-type.d b/docs/cmdline-opts/cert-type.d
index 55d8033b45..1232ec10d9 100644
--- a/docs/cmdline-opts/cert-type.d
+++ b/docs/cmdline-opts/cert-type.d
@@ -1,7 +1,7 @@
 Long: cert-type
 Protocols: TLS
 Arg: <type>
-Help: Certificate file type
+Help: Certificate type (DER/PEM/ENG)
 See-also: cert key key-type
 ---
 Tells curl what type the provided client certificate is using. PEM, DER, ENG