diff --git a/include/spdlog/details/circular_q.h b/include/spdlog/details/circular_q.h
index a37b7770..60b8d157 100644
--- a/include/spdlog/details/circular_q.h
+++ b/include/spdlog/details/circular_q.h
@@ -75,7 +75,7 @@ public:
     // Return number of elements actually stored
     size_t size() const
     {
-        if (tail_ > head_)
+        if (tail_ >= head_)
         {
            return tail_ - head_;
         }