diff --git a/src/App.tsx b/src/App.tsx
index a3ec488..686afad 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -10,6 +10,7 @@ import 'tippy.js/animations/shift-away.css';
 import './app.sass';
 
 import { Icon } from '@iconify-icon/solid';
+import { sizeFmt } from './utils';
 
 interface File {
   name: string 
@@ -25,11 +26,6 @@ const host = "https://daisy-ddns.hydev.org/data/api"
 const path = window.location.pathname
 const fetchApi = async () => await (await fetch(urlJoin(host, path))).json() as File[]
 
-function sizeFmt(size: number) {
-  var i = size == 0 ? 0 : Math.floor(Math.log(size) / Math.log(1024));
-  return (size / Math.pow(1024, i)).toFixed(1) + ' ' + ['B', 'kB', 'MB', 'GB', 'TB'][i];
-}
-
 function getIcon(f: File)
 {
   if (f.type == "directory") return "/mime/folder.svg"
diff --git a/src/utils.ts b/src/utils.ts
new file mode 100644
index 0000000..5deab9c
--- /dev/null
+++ b/src/utils.ts
@@ -0,0 +1,10 @@
+/**
+ * Format bytes to human-readable size
+ * 
+ * @param size Size in bytes
+ * @returns Human readable size in string
+ */
+export function sizeFmt(size: number): string {
+    var i = size == 0 ? 0 : Math.floor(Math.log(size) / Math.log(1024));
+    return (size / Math.pow(1024, i)).toFixed(1) + ' ' + ['B', 'kB', 'MB', 'GB', 'TB'][i];
+}
\ No newline at end of file