diff --git a/views/bootstrap/styles/application.js b/views/bootstrap/styles/application.js
index d463d1779..de2fe8996 100644
--- a/views/bootstrap/styles/application.js
+++ b/views/bootstrap/styles/application.js
@@ -38,6 +38,38 @@ function escapeHtml(text) {
   return text.replace(/[&<>"']/g, function(m) { return map[m]; });
 }
 
+/**
+ * Format bytes as human-readable text.
+ * 
+ * @param bytes Number of bytes.
+ * @param si True to use metric (SI) units, aka powers of 1000. False to use 
+ *           binary (IEC), aka powers of 1024.
+ * @param dp Number of decimal places to display.
+ * 
+ * @return Formatted string.
+ */
+function formatFileSize(bytes, si=false, dp=1) {
+  const thresh = si ? 1000 : 1024;
+
+  if (Math.abs(bytes) < thresh) {
+    return bytes + ' B';
+  }
+
+  const units = si 
+    ? ['kB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'] 
+    : ['KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB'];
+  let u = -1;
+  const r = 10**dp;
+
+  do {
+    bytes /= thresh;
+    ++u;
+  } while (Math.round(Math.abs(bytes) * r) / r >= thresh && u < units.length - 1);
+
+
+  return bytes.toFixed(dp) + ' ' + units[u];
+}
+
 function treeFolderSelected(formid, nodeid, nodename) {
 	$('#'+formid).val(nodeid);
 	$('#choosefoldersearch'+formid).val(nodename);
diff --git a/views/bootstrap4/styles/application.js b/views/bootstrap4/styles/application.js
index 4f22e48e0..244fa391c 100644
--- a/views/bootstrap4/styles/application.js
+++ b/views/bootstrap4/styles/application.js
@@ -38,6 +38,38 @@ function escapeHtml(text) {
   return text.replace(/[&<>"']/g, function(m) { return map[m]; });
 }
 
+/**
+ * Format bytes as human-readable text.
+ * 
+ * @param bytes Number of bytes.
+ * @param si True to use metric (SI) units, aka powers of 1000. False to use 
+ *           binary (IEC), aka powers of 1024.
+ * @param dp Number of decimal places to display.
+ * 
+ * @return Formatted string.
+ */
+function formatFileSize(bytes, si=false, dp=1) {
+  const thresh = si ? 1000 : 1024;
+
+  if (Math.abs(bytes) < thresh) {
+    return bytes + ' B';
+  }
+
+  const units = si 
+    ? ['kB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'] 
+    : ['KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB'];
+  let u = -1;
+  const r = 10**dp;
+
+  do {
+    bytes /= thresh;
+    ++u;
+  } while (Math.round(Math.abs(bytes) * r) / r >= thresh && u < units.length - 1);
+
+
+  return bytes.toFixed(dp) + ' ' + units[u];
+}
+
 function treeFolderSelected(formid, nodeid, nodename) {
 	$('#'+formid).val(nodeid);
 	$('#choosefoldersearch'+formid).val(nodename);