diff --git a/plate-tool-eframe/src/app.rs b/plate-tool-eframe/src/app.rs
index 652006e..d1044b9 100644
--- a/plate-tool-eframe/src/app.rs
+++ b/plate-tool-eframe/src/app.rs
@@ -22,6 +22,7 @@ pub struct MainWindowState {
     pub show_side_panel: bool,
     pub plate_display_options: PlateDisplayOptions,
     pub csv_export_type: CsvExportType,
+    pub show_plates_horizontal: bool,
 }
 
 impl Default for MainWindowState {
@@ -30,6 +31,7 @@ impl Default for MainWindowState {
             show_side_panel: true,
             plate_display_options: PlateDisplayOptions::default(),
             csv_export_type: CsvExportType::default(),
+            show_plates_horizontal: false,
         }
     }
 }
@@ -149,45 +151,85 @@ impl eframe::App for PlateToolEframe {
             ids.sort_unstable();
             ids
         };
+
+        fn add_plates(
+            ui: &mut egui::Ui,
+            main_state: &MainState,
+            current_transfer_state: &CurrentTransferState,
+            source_plate_state: &Mutex<PlateUiState>,
+            destination_plate_state: &Mutex<PlateUiState>,
+            main_window_state: &MainWindowState,
+            plate_size: egui::Vec2,
+            ordered_ids: Vec<plate_tool_lib::uuid::Uuid>,
+        ) {
+            if let Some(source_pi) = main_state.get_current_source_plateinstance() {
+                add_plate(
+                    plate_size,
+                    source_pi.plate.plate_format,
+                    main_state.get_current_source_transfers(),
+                    plate_tool_lib::plate::PlateType::Source,
+                    &ordered_ids,
+                    &main_state.transfer_region_cache,
+                    Some(&current_transfer_state),
+                    ui,
+                    source_plate_state.lock().unwrap().deref_mut(),
+                    main_window_state.plate_display_options,
+                );
+            }
+            if let Some(destination_pi) = main_state.get_current_destination_plateinstance() {
+                add_plate(
+                    plate_size,
+                    destination_pi.plate.plate_format,
+                    main_state.get_current_destination_transfers(),
+                    plate_tool_lib::plate::PlateType::Destination,
+                    &ordered_ids,
+                    &main_state.transfer_region_cache,
+                    Some(&current_transfer_state),
+                    ui,
+                    destination_plate_state.lock().unwrap().deref_mut(),
+                    main_window_state.plate_display_options,
+                );
+            }
+        }
         egui::CentralPanel::default().show(ctx, |ui| {
-            ui.vertical(|ui| {
-                let available_size = ui.available_size();
-                let half_height = {
-                    let mut x = available_size;
-                    x.y /= 2.0;
-                    x
-                };
-                if let Some(source_pi) = self.main_state.get_current_source_plateinstance() {
-                    add_plate(
-                        half_height,
-                        source_pi.plate.plate_format,
-                        self.main_state.get_current_source_transfers(),
-                        plate_tool_lib::plate::PlateType::Source,
-                        &ordered_ids,
-                        &self.main_state.transfer_region_cache,
-                        Some(&self.current_transfer_state),
+            let available_size = ui.available_size();
+            if !self.main_window_state.show_plates_horizontal {
+                ui.vertical(|ui| {
+                    let plate_size = {
+                        let mut x = available_size;
+                        x.y /= 2.0;
+                        x
+                    };
+                    add_plates(
                         ui,
-                        self.source_plate_state.lock().unwrap().deref_mut(),
-                        self.main_window_state.plate_display_options,
+                        &self.main_state,
+                        &self.current_transfer_state,
+                        &self.source_plate_state,
+                        &self.destination_plate_state,
+                        &self.main_window_state,
+                        plate_size,
+                        ordered_ids,
                     );
-                }
-                if let Some(destination_pi) =
-                    self.main_state.get_current_destination_plateinstance()
-                {
-                    add_plate(
-                        half_height,
-                        destination_pi.plate.plate_format,
-                        self.main_state.get_current_destination_transfers(),
-                        plate_tool_lib::plate::PlateType::Destination,
-                        &ordered_ids,
-                        &self.main_state.transfer_region_cache,
-                        Some(&self.current_transfer_state),
+                });
+            } else {
+                ui.horizontal(|ui| {
+                    let plate_size = {
+                        let mut x = available_size;
+                        x.x /= 2.0;
+                        x
+                    };
+                    add_plates(
                         ui,
-                        self.destination_plate_state.lock().unwrap().deref_mut(),
-                        self.main_window_state.plate_display_options,
+                        &self.main_state,
+                        &self.current_transfer_state,
+                        &self.source_plate_state,
+                        &self.destination_plate_state,
+                        &self.main_window_state,
+                        plate_size,
+                        ordered_ids,
                     );
-                }
-            });
+                });
+            }
         });
 
         // Modal processing
diff --git a/plate-tool-eframe/src/upper_menu.rs b/plate-tool-eframe/src/upper_menu.rs
index 4eea045..1086352 100644
--- a/plate-tool-eframe/src/upper_menu.rs
+++ b/plate-tool-eframe/src/upper_menu.rs
@@ -186,5 +186,6 @@ fn render_options_menu(
     });
     ui.menu_button("Windows", |ui| {
         ui.toggle_value(&mut main_window_state.show_side_panel, "Toggle side panel");
+        ui.toggle_value(&mut main_window_state.show_plates_horizontal, "Show plates horizontally");
     });
 }