diff --git a/renderdoc/driver/gl/gl_overlay.cpp b/renderdoc/driver/gl/gl_overlay.cpp
index b4eb768de..1a8f7f09d 100644
--- a/renderdoc/driver/gl/gl_overlay.cpp
+++ b/renderdoc/driver/gl/gl_overlay.cpp
@@ -375,10 +375,10 @@ ResourceId GLReplay::RenderOverlay(ResourceId texid, CompType typeHint, DebugOve
       gl.glGetNamedBufferParameterivEXT(idxbuf, eGL_BUFFER_SIZE, (GLint *)&length);
 
       idxs.resize(length);
-      gl.glGetBufferSubData(
-          eGL_ELEMENT_ARRAY_BUFFER, offset,
-          RDCMIN(GLsizeiptr(length - offset), GLsizeiptr(draw->numIndices) * draw->indexByteWidth),
-          &idxs[0]);
+      gl.glGetBufferSubData(eGL_ELEMENT_ARRAY_BUFFER, offset,
+                            RDCMIN(GLsizeiptr(length - offset),
+                                   GLsizeiptr(draw->numIndices) * GLsizeiptr(draw->indexByteWidth)),
+                            &idxs[0]);
 
       // unbind the real index buffer
       gl.glBindBuffer(eGL_ELEMENT_ARRAY_BUFFER, 0);