diff --git a/TinySTL/Detail/CircularBuffer.impl.h b/TinySTL/Detail/CircularBuffer.impl.h
index 9ba141596703bc4d76203d66c8e51d494c368ed2..83d3cfb5c5e6d5636765811f3a97c60abd3826fe 100644
--- a/TinySTL/Detail/CircularBuffer.impl.h
+++ b/TinySTL/Detail/CircularBuffer.impl.h
@@ -55,7 +55,7 @@ namespace TinySTL{
 		cb_iter<T, N, Alloc> operator +(const cb_iter<T, N, Alloc>& cit, std::ptrdiff_t i){
 			int real_i = i % (std::ptrdiff_t)N;//assume i >= 0
 			if (real_i < 0)
-				real_i += 5;
+				real_i += N;
 			cb_iter<T, N, Alloc> res = cit;
 			res.setIndex_(res.index_ + real_i);
 			res.setPtr_(res.ptr_ + res.index_);