diff --git a/src/formatSizeToClose.js b/src/formatSizeToClose.js
new file mode 100644
index 0000000..8b7e540
--- /dev/null
+++ b/src/formatSizeToClose.js
@@ -0,0 +1,17 @@
+function formatSizeToClose(size) {
+  if (typeof size !== 'number') {
+    throw new Error('Size must be a number');
+  }
+  const units = ['B', 'KB', 'MB', 'GB'];
+  let unitIndex = 0;
+  while (size >= 1024 && unitIndex < units.length - 1) {
+    size /= 1024;
+    unitIndex++;
+  }
+  return `${size.toFixed(2)} ${units[unitIndex]}`;
+}
+
+// Example usage:
+console.log(formatSizeToClose(500)); // '0.49 KB'
+console.log(formatSizeToClose(1500)); // '1.46 KB'
+console.log(formatSizeToClose(2000000)); // '1.91 MB'
\ No newline at end of file