diff --git a/kitty/glfw.c b/kitty/glfw.c
index 8024c5952..8fb5763eb 100644
--- a/kitty/glfw.c
+++ b/kitty/glfw.c
@@ -294,6 +294,22 @@ _set_title(Window *self, PyObject *args) {
     Py_RETURN_NONE;
 }
 
+
+static PyObject*
+get_framebuffer_size(Window *self) {
+    int w, h;
+    glfwGetFramebufferSize(self->window, &w, &h);
+    return Py_BuildValue("ii", w, h);
+}
+
+static PyObject*
+get_window_size(Window *self) {
+    int w, h;
+    glfwGetWindowSize(self->window, &w, &h);
+    return Py_BuildValue("ii", w, h);
+}
+
+
 // Boilerplate {{{
 #define MND(name, args) {#name, (PyCFunction)name, args, ""}
 
@@ -302,6 +318,8 @@ static PyMethodDef methods[] = {
     MND(get_clipboard_string, METH_NOARGS),
     MND(get_cursor_pos, METH_NOARGS),
     MND(should_close, METH_NOARGS),
+    MND(get_framebuffer_size, METH_NOARGS),
+    MND(get_window_size, METH_NOARGS),
     MND(set_should_close, METH_VARARGS),
     MND(set_input_mode, METH_VARARGS),
     MND(is_key_pressed, METH_VARARGS),
diff --git a/kitty/main.py b/kitty/main.py
index 0dca08535..044064b5d 100644
--- a/kitty/main.py
+++ b/kitty/main.py
@@ -101,6 +101,7 @@ def run_app(opts, args):
         viewport_size.width, viewport_size.height, args.cls)
     window.set_title(appname)
     window.make_context_current()
+    viewport_size.width, viewport_size.height = window.get_framebuffer_size()
     glewInit()
     boss = Boss(window, opts, args)
     boss.start()