diff --git a/src/backends/meta-monitor.c b/src/backends/meta-monitor.c
index f4d71f047..07857e00b 100644
--- a/src/backends/meta-monitor.c
+++ b/src/backends/meta-monitor.c
@@ -817,19 +817,19 @@ calculate_tile_coordinate (MetaMonitor         *monitor,
         case META_MONITOR_TRANSFORM_270:
         case META_MONITOR_TRANSFORM_FLIPPED_270:
           if (other_output->tile_info.loc_v_tile == output->tile_info.loc_v_tile &&
-              other_output->tile_info.loc_h_tile < output->tile_info.loc_h_tile)
+              other_output->tile_info.loc_h_tile > output->tile_info.loc_h_tile)
             y += other_output->tile_info.tile_w;
           if (other_output->tile_info.loc_h_tile == output->tile_info.loc_h_tile &&
-              other_output->tile_info.loc_v_tile < output->tile_info.loc_v_tile)
+              other_output->tile_info.loc_v_tile > output->tile_info.loc_v_tile)
             x += other_output->tile_info.tile_h;
           break;
         case META_MONITOR_TRANSFORM_90:
         case META_MONITOR_TRANSFORM_FLIPPED_90:
           if (other_output->tile_info.loc_v_tile == output->tile_info.loc_v_tile &&
-              other_output->tile_info.loc_h_tile > output->tile_info.loc_h_tile)
+              other_output->tile_info.loc_h_tile < output->tile_info.loc_h_tile)
             y += other_output->tile_info.tile_w;
           if (other_output->tile_info.loc_h_tile == output->tile_info.loc_h_tile &&
-              other_output->tile_info.loc_v_tile > output->tile_info.loc_v_tile)
+              other_output->tile_info.loc_v_tile < output->tile_info.loc_v_tile)
             x += other_output->tile_info.tile_h;
           break;
         }
diff --git a/src/tests/monitor-unit-tests.c b/src/tests/monitor-unit-tests.c
index ad0cdda62..883de1bd0 100644
--- a/src/tests/monitor-unit-tests.c
+++ b/src/tests/monitor-unit-tests.c
@@ -4828,12 +4828,13 @@ meta_test_monitor_custom_second_rotated_tiled_config (void)
           .current_mode = 1,
           .transform = META_MONITOR_TRANSFORM_90,
           .x = 1024,
-          .y = 400,
+          .y = 0,
         },
         {
           .current_mode = 1,
           .transform = META_MONITOR_TRANSFORM_90,
           .x = 1024,
+          .y = 400,
         }
       },
       .n_crtcs = 3,