diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index c12d4dedaef..8c4f435affe 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -169,17 +169,18 @@ module ts {
 
     function writeCommentRange(currentSourceFile: SourceFile, writer: EmitTextWriter, comment: CommentRange, newLine: string){
         if (currentSourceFile.text.charCodeAt(comment.pos + 1) === CharacterCodes.asterisk) {
-            var firstCommentLineAndCharacter = getOneBasedLineAndCharacterOfPosition(currentSourceFile, comment.pos);
-            var lastLine = getLineStarts(currentSourceFile).length;
+            var firstCommentLineAndCharacter = getZeroBasedLineAndCharacterOfPosition(currentSourceFile, comment.pos);
+            var lineCount = getLineStarts(currentSourceFile).length;
             var firstCommentLineIndent: number;
             for (var pos = comment.pos, currentLine = firstCommentLineAndCharacter.line; pos < comment.end; currentLine++) {
-                var nextLineStart = currentLine === lastLine ? (comment.end + 1) : getPositionOfOneBasedLineAndCharacter(currentSourceFile, currentLine + 1, /*character*/1);
+                var nextLineStart = (currentLine + 1) === lineCount
+                    ? currentSourceFile.text.length + 1
+                    : getStartPositionOfZeroBasedLine(currentLine + 1, currentSourceFile);
 
                 if (pos !== comment.pos) {
                     // If we are not emitting first line, we need to write the spaces to adjust the alignment
                     if (firstCommentLineIndent === undefined) {
-                        firstCommentLineIndent = calculateIndent(getPositionOfOneBasedLineAndCharacter(currentSourceFile, firstCommentLineAndCharacter.line, /*character*/1),
-                            comment.pos);
+                        firstCommentLineIndent = calculateIndent(getStartPositionOfZeroBasedLine(firstCommentLineAndCharacter.line, currentSourceFile), comment.pos);
                     }
 
                     // These are number of spaces writer is going to write at current indent
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 6323ffd4313..095044c4b8f 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -105,6 +105,16 @@ module ts {
         return <SourceFile>node;
     }
 
+    export function getStartPositionOfZeroBasedLine(line: number, sourceFile: SourceFile): number {
+        Debug.assert(line >= 0);
+        return getLineStarts(sourceFile)[line];
+    }
+
+    export function getStartPositionOfOneBasedLine(line: number, sourceFile: SourceFile): number {
+        Debug.assert(line >= 1);
+        return getLineStarts(sourceFile)[line - 1];
+    }
+
     // This is a useful function for debugging purposes.
     export function nodePosToString(node: Node): string {
         var file = getSourceFileOfNode(node);
diff --git a/src/services/formatting/formatting.ts b/src/services/formatting/formatting.ts
index 322c36bf7ad..b9cc0b24060 100644
--- a/src/services/formatting/formatting.ts
+++ b/src/services/formatting/formatting.ts
@@ -74,7 +74,7 @@ module ts.formatting {
         // get the span for the previous\current line
         var span = {
             // get start position for the previous line
-            pos: getStartPositionOfLine(line - 1, sourceFile),
+            pos: getStartPositionOfOneBasedLine(line - 1, sourceFile),
             // get end position for the current line (end value is exclusive so add 1 to the result)
             end: getEndLinePosition(line, sourceFile) + 1
         }
@@ -809,7 +809,7 @@ module ts.formatting {
             else {
                 var tokenStart = sourceFile.getOneBasedLineAndCharacterOfPosition(pos);
                 if (indentation !== tokenStart.character - 1) {
-                    var startLinePosition = getStartPositionOfLine(tokenStart.line, sourceFile);
+                    var startLinePosition = getStartPositionOfOneBasedLine(tokenStart.line, sourceFile);
                     recordReplace(startLinePosition, tokenStart.character - 1, indentationString);
                 }
             }
@@ -833,13 +833,13 @@ module ts.formatting {
                 for (var line = startLine; line < endLine; ++line) {
                     var endOfLine = getEndLinePosition(line, sourceFile);
                     parts.push({ pos: startPos, end: endOfLine });
-                    startPos = getStartPositionOfLine(line + 1, sourceFile);
+                    startPos = getStartPositionOfOneBasedLine(line + 1, sourceFile);
                 }
 
                 parts.push({ pos: startPos, end: commentRange.end });
             }
 
-            var startLinePos = getStartPositionOfLine(startLine, sourceFile);
+            var startLinePos = getStartPositionOfOneBasedLine(startLine, sourceFile);
 
             var nonWhitespaceColumnInFirstPart =
                 SmartIndenter.findFirstNonWhitespaceColumn(startLinePos, parts[0].pos, sourceFile, options);
@@ -857,7 +857,7 @@ module ts.formatting {
             // shift all parts on the delta size
             var delta = indentation - nonWhitespaceColumnInFirstPart;
             for (var i = startIndex, len = parts.length; i < len; ++i, ++startLine) {
-                var startLinePos = getStartPositionOfLine(startLine, sourceFile);
+                var startLinePos = getStartPositionOfOneBasedLine(startLine, sourceFile);
                 var nonWhitespaceColumn =
                     i === 0
                         ? nonWhitespaceColumnInFirstPart
@@ -876,7 +876,7 @@ module ts.formatting {
 
         function trimTrailingWhitespacesForLines(line1: number, line2: number, range?: TextRangeWithKind) {
             for (var line = line1; line < line2; ++line) {
-                var lineStartPosition = getStartPositionOfLine(line, sourceFile);
+                var lineStartPosition = getStartPositionOfOneBasedLine(line, sourceFile);
                 var lineEndPosition = getEndLinePosition(line, sourceFile);
 
                 // do not trim whitespaces in comments
diff --git a/src/services/utilities.ts b/src/services/utilities.ts
index 711fc0fde8d..41bd63560eb 100644
--- a/src/services/utilities.ts
+++ b/src/services/utilities.ts
@@ -32,11 +32,6 @@ module ts {
         }
     }
 
-    export function getStartPositionOfLine(line: number, sourceFile: SourceFile): number {
-        Debug.assert(line >= 1);
-        return sourceFile.getLineStarts()[line - 1];
-    }
-
     export function getLineStartPositionForPosition(position: number, sourceFile: SourceFile): number {
         var lineStarts = sourceFile.getLineStarts();
         var line = sourceFile.getOneBasedLineAndCharacterOfPosition(position).line;