diff --git a/inoculate/src/qemu.rs b/inoculate/src/qemu.rs
index 610c14ad..450b6714 100644
--- a/inoculate/src/qemu.rs
+++ b/inoculate/src/qemu.rs
@@ -33,7 +33,9 @@ pub enum Cmd {
         ///
         /// If a test run doesn't complete before this timeout has elapsed, it's
         /// considered to have failed.
-        #[clap(long, value_parser = parse_secs, default_value = "60")]
+        ///
+        /// By default, this is 20 minutes (1200 seconds).
+        #[clap(long, value_parser = parse_secs, default_value = "1200")]
         timeout_secs: Duration,
 
         /// Disables capturing test serial output.