diff --git a/phpBB/adm/style/acp_attachments.html b/phpBB/adm/style/acp_attachments.html
index d048191864..e1f7f140c9 100644
--- a/phpBB/adm/style/acp_attachments.html
+++ b/phpBB/adm/style/acp_attachments.html
@@ -196,7 +196,7 @@
 		</dl>
 		<dl>
 			<dt><label for="extgroup_filesize">{L_MAX_EXTGROUP_FILESIZE}{L_COLON}</label></dt>
-			<dd><input type="number" id="extgroup_filesize" min="0" max="999999999999999" name="max_filesize" value="{EXTGROUP_FILESIZE}" /> <select name="size_select">{S_EXT_GROUP_SIZE_OPTIONS}</select></dd>
+			<dd><input type="number" id="extgroup_filesize" min="0" max="999999999999999" step="any" name="max_filesize" value="{EXTGROUP_FILESIZE}" /> <select name="size_select">{S_EXT_GROUP_SIZE_OPTIONS}</select></dd>
 		</dl>
 		<dl>
 			<dt><label for="assigned_extensions">{L_ASSIGNED_EXTENSIONS}{L_COLON}</label></dt>
diff --git a/phpBB/includes/acp/acp_attachments.php b/phpBB/includes/acp/acp_attachments.php
index 7e348aa45b..8e8ace8337 100644
--- a/phpBB/includes/acp/acp_attachments.php
+++ b/phpBB/includes/acp/acp_attachments.php
@@ -1736,7 +1736,7 @@ class acp_attachments
 		$value = $filesize['value'];
 
 		// size and maxlength must not be specified for input of type number
-		return '<input type="number" id="' . $key . '" min="0" max="999999999999999" name="config[' . $key . ']" value="' . $value . '" /> <select name="' . $key . '">' . size_select_options($size_var) . '</select>';
+		return '<input type="number" id="' . $key . '" min="0" max="999999999999999" step="any" name="config[' . $key . ']" value="' . $value . '" /> <select name="' . $key . '">' . size_select_options($size_var) . '</select>';
 	}
 
 	/**