diff --git a/src/common/buffer/BufferRange.test.ts b/src/common/buffer/BufferRange.test.ts
index d0f287dc..69aacd99 100644
--- a/src/common/buffer/BufferRange.test.ts
+++ b/src/common/buffer/BufferRange.test.ts
@@ -16,10 +16,10 @@ describe('BufferRange', () => {
       assert.throws(() => getRangeLength(createRange(1, 3, 1, 1), 0));
     });
     it('should get range multiple lines', () => {
-      assert.equal(getRangeLength(createRange(1, 1, 4, 5), 5), 23);
+      assert.equal(getRangeLength(createRange(1, 1, 4, 5), 5), 24);
     });
     it('should get range for end line right after start line', () => {
-      assert.equal(getRangeLength(createRange(1, 1, 7, 2), 5), 11);
+      assert.equal(getRangeLength(createRange(1, 1, 7, 2), 5), 12);
     });
   });
 });
diff --git a/src/common/buffer/BufferRange.ts b/src/common/buffer/BufferRange.ts
index 9091c68d..a49cf481 100644
--- a/src/common/buffer/BufferRange.ts
+++ b/src/common/buffer/BufferRange.ts
@@ -5,12 +5,9 @@
 
 import { IBufferRange } from 'xterm';
 
-export function getRangeLength(range: IBufferRange, cols: number): number {
-  if (range.start.y === range.end.y) {
-    return range.end.x - range.start.x + 1;
-  }
+export function getRangeLength(range: IBufferRange, bufferCols: number): number {
   if (range.start.y > range.end.y) {
     throw new Error(`Buffer range end (${range.end.x}, ${range.end.y}) cannot be before start (${range.start.x}, ${range.start.y})`);
   }
-  return cols * (range.end.y - range.start.y - 1) + cols - range.start.x + range.end.x;
+  return bufferCols * (range.end.y - range.start.y) + (range.end.x - range.start.x + 1);
 }