diff --git a/include/output.h b/include/output.h
index 4fd3374..05ce095 100644
--- a/include/output.h
+++ b/include/output.h
@@ -51,3 +51,6 @@ void output_list_destroy(struct wl_list* list);
 struct output* output_find_by_id(struct wl_list* list, uint32_t id);
 struct output* output_find_by_name(struct wl_list* list, const char* name);
 struct output* output_first(struct wl_list* list);
+
+uint32_t output_get_transformed_width(const struct output* self);
+uint32_t output_get_transformed_height(const struct output* self);
diff --git a/src/output.c b/src/output.c
index d50efd6..317b224 100644
--- a/src/output.c
+++ b/src/output.c
@@ -18,6 +18,7 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <string.h>
+#include <stdbool.h>
 #include <wayland-client-protocol.h>
 #include <wayland-client.h>
 
@@ -27,6 +28,33 @@
 
 #include "xdg-output-unstable-v1.h"
 
+static bool is_transform_90_degrees(enum wl_output_transform transform)
+{
+	switch (transform) {
+	case WL_OUTPUT_TRANSFORM_90:
+	case WL_OUTPUT_TRANSFORM_270:
+	case WL_OUTPUT_TRANSFORM_FLIPPED_90:
+	case WL_OUTPUT_TRANSFORM_FLIPPED_270:
+		return true;
+	default:
+		break;
+	}
+
+	return false;
+}
+
+uint32_t output_get_transformed_width(const struct output* self)
+{
+	return is_transform_90_degrees(self->transform)
+	      ? self->height : self->width;
+}
+
+uint32_t output_get_transformed_height(const struct output* self)
+{
+	return is_transform_90_degrees(self->transform)
+	      ? self->width : self->height;
+}
+
 static void output_handle_geometry(void* data, struct wl_output* wl_output,
 				   int32_t x, int32_t y, int32_t phys_width,
 				   int32_t phys_height, int32_t subpixel,