diff --git a/Sources/LibMakeColors/Model/Scanner+ColorParser.swift b/Sources/LibMakeColors/Model/Scanner+ColorParser.swift
index d114d4a..9870824 100644
--- a/Sources/LibMakeColors/Model/Scanner+ColorParser.swift
+++ b/Sources/LibMakeColors/Model/Scanner+ColorParser.swift
@@ -182,6 +182,7 @@ extension Scanner {
         }
 
         if string("%") {
+            guard 0...100 ~= int else { return nil }
             int = int * 0xFF / 100
         }