diff --git a/lib/monaco-adapter.js b/lib/monaco-adapter.js
index 11b0d2dc2..ec0fcc0b7 100644
--- a/lib/monaco-adapter.js
+++ b/lib/monaco-adapter.js
@@ -58,13 +58,13 @@ firepad.MonacoAdapter = (function() {
   MonacoAdapter.prototype.operationFromMonacoChange = function(change) {
     text = change.changes[0].text;
     start = this.indexFromPos(change.changes[0].range, 'start');
-    restLength = this.lastDocLines.join('\n').length - start;
+    restLength = this.lastDocLines.join(this.monacoModel.getEOL()).length - start;
     text_ins = change.changes[0].text;
     rangeLen = change.changes[0].rangeLength;
 
     if (change.changes[0].rangeLength > 0) {
       restLength -= rangeLen;
-      text = this.lastDocLines.join('\n')
+      text = this.lastDocLines.join(this.monacoModel.getEOL())
           .slice(start, start+rangeLen);
     }
 
@@ -137,7 +137,7 @@ firepad.MonacoAdapter = (function() {
       if (index <= line.length) {
         break;
       }
-      index -= line.length + 1;
+      index -= line.length + this.monacoModel.getEOL().length;
     }
     return {
       row: row + 1,
@@ -154,12 +154,12 @@ firepad.MonacoAdapter = (function() {
     index = 0;
     if (upto === 'start') {
       for (row = 1; row < range.startLineNumber; row++) {
-        index += lines[row-1].length + 1
+        index += lines[row-1].length + this.monacoModel.getEOL().length;
       }
       return index + range.startColumn -1;
     } else {
       for (row = 1; row < range.endLineNumber; row++) {
-        index += lines[row-1].length + 1
+        index += lines[row-1].length + this.monacoModel.getEOL().length;
       }
       return index + range.endColumn -1;
     }