diff --git a/imgui_draw.cpp b/imgui_draw.cpp
index d89e36a9a..0c3f4e95a 100644
--- a/imgui_draw.cpp
+++ b/imgui_draw.cpp
@@ -2230,8 +2230,8 @@ void ImDrawListSplitter::Merge(ImDrawList* draw_list)
     for (int i = 1; i < _Count; i++)
     {
         ImDrawChannel& ch = _Channels[i];
-        if (int sz = ch._CmdBuffer.Size) { memcpy(cmd_write, ch._CmdBuffer.Data, sz * sizeof(ImDrawCmd)); cmd_write += sz; }
-        if (int sz = ch._IdxBuffer.Size) { memcpy(idx_write, ch._IdxBuffer.Data, sz * sizeof(ImDrawIdx)); idx_write += sz; }
+        if (int sz = ch._CmdBuffer.Size) { memcpy(cmd_write, ch._CmdBuffer.Data, (size_t)sz * sizeof(ImDrawCmd)); cmd_write += sz; }
+        if (int sz = ch._IdxBuffer.Size) { memcpy(idx_write, ch._IdxBuffer.Data, (size_t)sz * sizeof(ImDrawIdx)); idx_write += sz; }
     }
     draw_list->_IdxWritePtr = idx_write;