diff --git a/Website/__init__.py b/Website/__init__.py
index 87ec39c..ccd81b7 100644
--- a/Website/__init__.py
+++ b/Website/__init__.py
@@ -83,7 +83,7 @@ def create_app(test_config=None):
         users = c.fetchall()
         text = ""
         for i in users:
-            text = text + f'<p><a href="list/user?id={i[0]}">{escape(i[1])}</a>: {i[2]}€ <form action="/change" method="post"><input name="id" type="hidden" value="{i[0]}"> <input name="change" type="number" step="0.1" placeholder="add to balance"></form></p> <br style="line-height: 50%;"></br>'
+            text = text + f'<p><a href="list/user?id={i[0]}">{escape(i[1])}</a>: {i[2]}€ <form action="/change" method="post"><input name="id" type="hidden" value="{i[0]}"> <input name="change" type="number" pattern="[0-9]+([,\.][0-9]+)?" step="0.1" placeholder="add to balance"></form></p> <br style="line-height: 50%;"></br>'
         return '''<!DOCTYPE html>
             <html lang="en">
             <script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/4.0.1/socket.io.js" integrity="sha512-q/dWJ3kcmjBLU4Qc47E4A9kTB4m3wuTY7vkFJDTZKjTs8jhyGQnaUrxa0Ytd0ssMZhbNua9hE+E7Qv1j+DyZwA==" crossorigin="anonymous"></script>
@@ -137,7 +137,7 @@ def create_app(test_config=None):
                 <p> {escape(user[1])} : {user[2]}€ <p>
                 <form action="/addtag" method="post"><input name="id" type="hidden" value="{user[0]}"><button type="submit">Add Tag</button></form>
                 <form action="/removetag" method="post"><input name="id" type="hidden" value="{user[0]}"><button type="submit">Remove Tag</button></form>
-                </p><form action="/change" method="post"><input name="id" type="hidden" value="{user[0]}"> <input name="change" type="number" step="0.1" placeholder="change balance"></form>
+                </p><form action="/change" method="post"><input name="id" type="hidden" value="{user[0]}"> <input name="change" type="number" pattern="[0-9]+([,\.][0-9]+)?" step="0.1" placeholder="change balance"></form>
                 </p>
                 <br></br>
                 <p>Tags:</p>
