diff --git a/utils.c b/utils.c
index 1cc2be8..06de445 100644
--- a/utils.c
+++ b/utils.c
@@ -299,6 +299,43 @@ page_calc_height_width(zathura_page_t* page, unsigned int* page_height, unsigned
   }
 }
 
+void
+zathura_get_document_size(zathura_t* zathura,
+                          unsigned int cell_height, unsigned int cell_width,
+                          unsigned int* height, unsigned int* width)
+{
+  g_return_if_fail(zathura != NULL && zathura->document != NULL &&
+                   height != NULL && width != NULL);
+
+  unsigned int pages_per_row = 1;
+  girara_setting_get(zathura->ui.session, "pages-per-row", &pages_per_row);
+  if (pages_per_row == 0)
+    pages_per_row = 1;
+
+  unsigned int first_page_column = 1;
+  girara_setting_get(zathura->ui.session, "first-page-column", &first_page_column);
+  if (first_page_column < 1)
+    first_page_column = 1;
+  if (first_page_column > pages_per_row)
+    first_page_column = (first_page_column - 1) % pages_per_row + 1;
+
+  int padding = 1;
+  girara_setting_get(zathura->ui.session, "page-padding", &padding);
+
+  double scale = zathura_document_get_scale(zathura->document);
+
+  cell_height = ceil(cell_height * scale);
+  cell_width  = ceil(cell_width * scale);
+
+  *width = pages_per_row * cell_width + (pages_per_row - 1) * padding;
+  unsigned int effective_number_of_pages =
+    zathura_document_get_number_of_pages(zathura->document) +
+    first_page_column - 1;
+  unsigned int rows = effective_number_of_pages / pages_per_row +
+                     (effective_number_of_pages % pages_per_row ? 1 : 0);
+  *height = rows * cell_height + (rows - 1) * padding;
+}
+
 GtkWidget*
 zathura_page_get_widget(zathura_t* zathura, zathura_page_t* page)
 {
diff --git a/utils.h b/utils.h
index b531731..45990d0 100644
--- a/utils.h
+++ b/utils.h
@@ -104,6 +104,23 @@ void set_adjustment(GtkAdjustment* adjust, gdouble value);
 void
 page_calc_height_width(zathura_page_t* page, unsigned int* page_height, unsigned int* page_width, bool rotate);
 
+/**
+ * Compute the size of the entire document to be displayed (in pixels), taking
+ * into account the scale, the layout of the pages, and the padding between
+ * them. It should be equal to the allocation of zathura->ui.page_widget once
+ * it's shown.
+ *
+ * @param[in]  zathura                The zathura instance
+ * @param[in]  cell_height,cell_width The height and width of a cell containing
+ *                                    a single page; it should be obtained
+ *                                    using zathura_document_get_cell_size()
+ *                                    with the document scale set to 1.0
+ * @param[out] height,width           The height and width of the document
+ */
+void zathura_get_document_size(zathura_t* zathura,
+                               unsigned int cell_height, unsigned int cell_width,
+                               unsigned int* height, unsigned int* width);
+
 /**
  * Returns the page widget of the page
  *