diff --git a/src/bank.cpp b/src/bank.cpp
index ad6dd46..ebe5f8c 100644
--- a/src/bank.cpp
+++ b/src/bank.cpp
@@ -36,7 +36,7 @@ inline bool ValidUsername(const std::string &name) noexcept
     }
     for (char c : name)
     {
-        if (!((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || c == '_'))
+        if (!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || c == '_'))
         {
             return false;
         }
diff --git a/src/user_filter.cpp b/src/user_filter.cpp
index 95d6bad..c5fc5c3 100644
--- a/src/user_filter.cpp
+++ b/src/user_filter.cpp
@@ -8,7 +8,7 @@ inline bool ValidUsername(const std::string &name) noexcept
     }
     for (char c : name)
     {
-        if (!((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || c == '_'))
+        if (!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || c == '_'))
         {
             return false;
         }