diff --git a/src/pyj/read_book/prefs/layout.pyj b/src/pyj/read_book/prefs/layout.pyj
index 8af10a1023..3ce6966d93 100644
--- a/src/pyj/read_book/prefs/layout.pyj
+++ b/src/pyj/read_book/prefs/layout.pyj
@@ -55,7 +55,7 @@ def create_layout_panel(container):
         E.tr(E.td(_('In landscape orientation:')), E.td(E.input(type='number', name='landscape', min='0', step='1', max='20', value=str(cps.landscape)))),
     ))
 
-    sec(_('Change the maximum screen area used to display text. A value of zero means that all available screen area is used.'))
+    sec(_('Change the maximum screen area (in pixels) used to display text. A value of zero means that all available screen area is used.'))
     container.appendChild(E.table(style='margin: 1ex 1rem', id=TEXT_AREA,
         E.tr(E.td(_('Max. width:')), E.td(E.input(type='number', name='width',   min='0', step='10', value=str(sd.get('max_text_width'))))),
         E.tr(E.td(_('Max. height:')), E.td(E.input(type='number', name='height', min='0', step='10', value=str(sd.get('max_text_height'))))),