diff --git a/photobooth.py b/photobooth.py
index b31f899..7c9e6d9 100755
--- a/photobooth.py
+++ b/photobooth.py
@@ -195,9 +195,17 @@ def box_dims_for(term_rows, term_cols, cfg=None):
     if cfg.printer_a4 and target_rows is not None:
         # The printed page is rotated 90 degrees before it reaches the
         # printer (see prepare_print_frame), so the box shown on screen
-        # should reflect that same landscape swap rather than the
-        # printer's raw portrait character grid.
-        target_cols, target_rows = target_rows, target_cols
+        # should have the same *visual* aspect ratio the final, rotated
+        # print will have - not just target_cols/target_rows swapped.
+        # Monospace glyphs are taller than wide (_CHAR_ASPECT), so a plain
+        # swap of the character counts still renders taller than wide;
+        # scale the box to fill the terminal at the correct ratio instead.
+        landscape_ratio = 1 / (visual_aspect(target_cols, target_rows) * _CHAR_ASPECT)
+        avail_cols, avail_rows = max_cols - 2, max_rows - 2
+        if avail_cols / avail_rows > landscape_ratio:
+            target_rows, target_cols = avail_rows, round(avail_rows * landscape_ratio)
+        else:
+            target_cols, target_rows = avail_cols, round(avail_cols / landscape_ratio)
     rows = max_rows if target_rows is None else max(min(target_rows + 2, max_rows), 3)
     cols = max(min(target_cols + 2, max_cols), 10)
     return rows, cols