diff --git a/cmd/curd/main.go b/cmd/curd/main.go
index 4d93e17..ce9b016 100644
--- a/cmd/curd/main.go
+++ b/cmd/curd/main.go
@@ -93,6 +93,13 @@ func main() {
 
 	flag.Parse()
 
+	// Validate PercentageToMarkComplete range (0-100) from CLI flag
+	if userCurdConfig.PercentageToMarkComplete < 0 {
+		userCurdConfig.PercentageToMarkComplete = 0
+	} else if userCurdConfig.PercentageToMarkComplete > 100 {
+		userCurdConfig.PercentageToMarkComplete = 100
+	}
+
 	// Check version before screen clearing
 	if *versionFlag {
 		fmt.Printf("Curd version: %s\n", resolvedVersion())
diff --git a/internal/config.go b/internal/config.go
index 6bceed0..db324f1 100755
--- a/internal/config.go
+++ b/internal/config.go
@@ -582,6 +582,13 @@ func PopulateConfig(configMap map[string]string) CurdConfig {
 		config.MpvArgs = parseStringArray(mpvArgs)
 	}
 
+	// Validate PercentageToMarkComplete range (0-100)
+	if config.PercentageToMarkComplete < 0 {
+		config.PercentageToMarkComplete = 0
+	} else if config.PercentageToMarkComplete > 100 {
+		config.PercentageToMarkComplete = 100
+	}
+
 	return config
 }