diff --git a/HISTORY.md b/HISTORY.md
index 78ff8dd..7963c23 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -3,6 +3,12 @@
 https://github.com/josdejong/jsoneditor
 
 
+## not yet published, version 8.1.1
+
+- Changed the file size reported in `preview` mode to `KB` and `MB` instead of 
+  `KiB` and `MiB` in order to match the size reported by filesystems.
+
+
 ## 2019-12-18, version 8.1.0
 
 - Implemented `popupAnchor` allowing to select a custom anchor element. 
diff --git a/src/js/util.js b/src/js/util.js
index 075b4b8..573657e 100644
--- a/src/js/util.js
+++ b/src/js/util.js
@@ -1371,7 +1371,7 @@ export function isTimestamp (field, value) {
 
 /**
  * Return a human readable document size
- * For example formatSize(7570718) outputs '7.2 MiB'
+ * For example formatSize(7570718) outputs '7.6 MB'
  * @param {number} size
  * @return {string} Returns a human readable size
  */
@@ -1380,23 +1380,23 @@ export function formatSize (size) {
     return size.toFixed() + ' B'
   }
 
-  const KiB = size / 1024
-  if (KiB < 900) {
-    return KiB.toFixed(1) + ' KiB'
+  const KB = size / 1000
+  if (KB < 900) {
+    return KB.toFixed(1) + ' KB'
   }
 
-  const MiB = KiB / 1024
-  if (MiB < 900) {
-    return MiB.toFixed(1) + ' MiB'
+  const MB = KB / 1000
+  if (MB < 900) {
+    return MB.toFixed(1) + ' MB'
   }
 
-  const GiB = MiB / 1024
-  if (GiB < 900) {
-    return GiB.toFixed(1) + ' GiB'
+  const GB = MB / 1000
+  if (GB < 900) {
+    return GB.toFixed(1) + ' GB'
   }
 
-  const TiB = GiB / 1024
-  return TiB.toFixed(1) + ' TiB'
+  const TB = GB / 1000
+  return TB.toFixed(1) + ' TB'
 }
 
 /**
diff --git a/test/util.test.js b/test/util.test.js
index fcbf205..549550b 100644
--- a/test/util.test.js
+++ b/test/util.test.js
@@ -484,14 +484,13 @@ describe('util', () => {
 
   it('should format a document size in a human readable way', () => {
     assert.strictEqual(formatSize(500), '500 B')
-    assert.strictEqual(formatSize(900), '0.9 KiB')
-    assert.strictEqual(formatSize(77.89 * 1024), '77.9 KiB')
-    assert.strictEqual(formatSize(950 * 1024), '0.9 MiB')
-    assert.strictEqual(formatSize(7.22 * 1024 * 1024), '7.2 MiB')
-    assert.strictEqual(formatSize(955.4 * 1024 * 1024), '0.9 GiB')
-    assert.strictEqual(formatSize(22.37 * 1024 * 1024 * 1024), '22.4 GiB')
-    assert.strictEqual(formatSize(1024 * 1024 * 1024 * 1024), '1.0 TiB')
-  })
+    assert.strictEqual(formatSize(900), '0.9 KB')
+    assert.strictEqual(formatSize(77.89 * 1000), '77.9 KB')
+    assert.strictEqual(formatSize(950 * 1000), '0.9 MB')
+    assert.strictEqual(formatSize(7.22 * 1000 * 1000), '7.2 MB')
+    assert.strictEqual(formatSize(945.4 * 1000 * 1000), '0.9 GB')
+    assert.strictEqual(formatSize(22.37 * 1000 * 1000 * 1000), '22.4 GB')
+    assert.strictEqual(formatSize(1000 * 1000 * 1000 * 1000), '1.0 TB')  })
 
   it('should limit characters', () => {
     assert.strictEqual(limitCharacters('hello world', 11), 'hello world')