diff --git a/tool_core.js b/tool_core.js
index a11e368..730c25a 100644
--- a/tool_core.js
+++ b/tool_core.js
@@ -433,9 +433,9 @@ module.exports = {
     // segment a number with a space between each 3 digits
     let segmented = sizeBytes.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ' ')
     const parts = segmented.split(' ')
-    parts[parts.length - 3] += 'm'
-    parts[parts.length - 2] += 'k'
-    return parts.join(' ') + 'b'
+    parts[parts.length - 3] += 'M'
+    parts[parts.length - 2] += 'K'
+    return parts.join(' ') + 'B'
   },
 
   get_file_ext (filename = '') {