diff --git a/crates/ui-egui/src/backstage.rs b/crates/ui-egui/src/backstage.rs
index d667c95..922baab 100644
--- a/crates/ui-egui/src/backstage.rs
+++ b/crates/ui-egui/src/backstage.rs
@@ -962,6 +962,12 @@ fn options(app: &mut SheetApp, ui: &mut Ui) {
         app.run_or_alert("view.formulaBar", json!({"on": formula_bar}));
     }
     ui.add_space(18.0);
+    section(ui, lang, "Options|Editing");
+    let mut autocomplete = app.ui.autocomplete;
+    if ui.checkbox(&mut autocomplete, lang.tr("Enable AutoComplete for cell values")).changed() {
+        app.run_or_alert("options.autoComplete", json!({"on": autocomplete}));
+    }
+    ui.add_space(18.0);
     section(ui, lang, "Options|Save");
     let mut autosave = app.grid.autosave();
     if ui.checkbox(&mut autosave, lang.tr("Save .xlsx workbooks automatically after every change")).changed() {
diff --git a/crates/ui-egui/src/control.rs b/crates/ui-egui/src/control.rs
index d27ea05..2ea5cfa 100644
--- a/crates/ui-egui/src/control.rs
+++ b/crates/ui-egui/src/control.rs
@@ -181,6 +181,7 @@ pub fn handle(app: &mut SheetApp, ctx: &egui::Context, method: &str, p: &Json) -
                 ("view.darkMode", "Dark Mode", ""),
                 ("view.theme", "Display Theme", ""),
                 ("view.animations", "Animations", "{on?: bool} (toggles without it) → {on}"),
+                ("options.autoComplete", "Enable AutoComplete for cell values", "{on?: bool} (toggles without it) → {on}"),
                 ("view.interfaceScale", "Interface Size", "{percent: 75–200 | \"auto\"} (100 = auto; clamped)"),
                 ("ui.dialog", "Open Dialog", ""),
                 ("ui.backstage", "File (Backstage view)", "{page?: home|new|open|info|saveAs|print|export|options|close}"),
diff --git a/crates/ui-egui/src/editor.rs b/crates/ui-egui/src/editor.rs
index 767f134..4aada29 100644
--- a/crates/ui-egui/src/editor.rs
+++ b/crates/ui-egui/src/editor.rs
@@ -251,9 +251,10 @@ pub fn column_completion(sheet: &gridcraft_engine::model::Sheet, at: CellRef, ty
         match sheet.value(CellRef::new(row, at.col)) {
             gridcraft_engine::core::Value::Empty => false,
             gridcraft_engine::core::Value::Text(t) => {
-                if t.to_lowercase().starts_with(&lower) && t.len() > typed.len() {
+                let folded = t.to_lowercase();
+                if folded.starts_with(&lower) && folded.len() > lower.len() {
                     match &found {
-                        Some(f) if !f.eq_ignore_ascii_case(&t) => ambiguous = true,
+                        Some(f) if f.to_lowercase() != folded => ambiguous = true,
                         None => found = Some(t.to_string()),
                         _ => {}
                     }
@@ -281,6 +282,13 @@ pub fn column_completion(sheet: &gridcraft_engine::model::Sheet, at: CellRef, ty
     if ambiguous { None } else { found }
 }
 
+/// The part of `full` after the `typed` prefix, counted in characters: case folding can change
+/// a character's byte length ("ß" is two bytes, "ẞ" three).
+pub fn completion_rest<'a>(full: &'a str, typed: &str) -> Option<&'a str> {
+    let start = full.char_indices().nth(typed.chars().count())?.0;
+    full.get(start..)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
diff --git a/crates/ui-egui/src/formula_bar.rs b/crates/ui-egui/src/formula_bar.rs
index 83278b1..7f1ad87 100644
--- a/crates/ui-egui/src/formula_bar.rs
+++ b/crates/ui-egui/src/formula_bar.rs
@@ -173,6 +173,10 @@ pub fn editor_widget(app: &mut SheetApp, ui: &mut egui::Ui, id: egui::Id, font:
             let enter = i.consume_key(egui::Modifiers::NONE, Key::Enter) || i.consume_key(egui::Modifiers::SHIFT, Key::Enter);
             let tab = i.consume_key(egui::Modifiers::NONE, Key::Tab) || i.consume_key(egui::Modifiers::SHIFT, Key::Tab);
             let esc = i.consume_key(egui::Modifiers::NONE, Key::Escape);
+            // Backspace takes back the AutoComplete proposal (Excel's selected rest), not a typed character.
+            if ed.completion.is_some() && i.consume_key(egui::Modifiers::NONE, Key::Backspace) {
+                ed.completion = None;
+            }
             (enter, tab, esc, alt_enter, cmd_enter, ctrl_shift_enter, m.shift)
         });
         if alt_enter {
@@ -198,6 +202,8 @@ pub fn editor_widget(app: &mut SheetApp, ui: &mut egui::Ui, id: egui::Id, font:
         if esc {
             if !ed.autocomplete.is_empty() {
                 ed.autocomplete.clear();
+            } else if ed.completion.is_some() {
+                ed.completion = None;
             } else {
                 cancel = true;
             }
@@ -305,7 +311,8 @@ pub fn editor_widget(app: &mut SheetApp, ui: &mut egui::Ui, id: egui::Id, font:
     }
     if resp.changed() {
         ed.completion = None;
-        if !ed.is_formula()
+        if app.ui.autocomplete
+            && !ed.is_formula()
             && ed.caret == ed.text.chars().count()
             && let Some(sh) = app.session.active().and_then(|d| d.wb.sheet(ed.sheet))
         {
@@ -329,8 +336,7 @@ pub fn editor_widget(app: &mut SheetApp, ui: &mut egui::Ui, id: egui::Id, font:
     }
     // Column AutoComplete: the rest of the suggested entry, shown selected after the caret.
     if let Some(full) = &ed.completion
-        && full.len() > ed.text.len()
-        && let Some(rest) = full.get(ed.text.len()..)
+        && let Some(rest) = crate::editor::completion_rest(full, &ed.text)
     {
         let pos = resp.rect.left_top() + egui::vec2(output.galley.rect.width(), 0.0);
         let g = ui.painter().layout_no_wrap(
diff --git a/crates/ui-egui/src/i18n.rs b/crates/ui-egui/src/i18n.rs
index 9b9511e..061698d 100644
--- a/crates/ui-egui/src/i18n.rs
+++ b/crates/ui-egui/src/i18n.rs
@@ -583,6 +583,7 @@ const JAPANESE: &[(&str, &str)] = &[
     ("Options|General", "全般"),
     ("Options|Save", "保存"),
     ("Show formula bar", "数式バーを表示する"),
+    ("Enable AutoComplete for cell values", "セルの値にオートコンプリートを使用する"),
     ("Save .xlsx workbooks automatically after every change", "変更のたびに .xlsx ブックを自動的に保存する"),
     ("Workbook calculation", "ブックの計算"),
     ("Enable iterative calculation", "反復計算を行う"),
diff --git a/crates/ui-egui/src/i18n/cs.rs b/crates/ui-egui/src/i18n/cs.rs
index e7c9ca6..7ed8372 100644
--- a/crates/ui-egui/src/i18n/cs.rs
+++ b/crates/ui-egui/src/i18n/cs.rs
@@ -319,6 +319,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Options|General" => "Obecné",
         "Options|Save" => "Uložit",
         "Show formula bar" => "Zobrazit řádek vzorců",
+        "Enable AutoComplete for cell values" => "Povolit automatické dokončování hodnot buněk",
         "Save .xlsx workbooks automatically after every change" => "Automaticky ukládat sešity .xlsx po každé změně",
         "Workbook calculation" => "Výpočet sešitu",
         "Enable iterative calculation" => "Povolit iterativní výpočet",
diff --git a/crates/ui-egui/src/i18n/de.rs b/crates/ui-egui/src/i18n/de.rs
index 6ceabdf..c20c7d1 100644
--- a/crates/ui-egui/src/i18n/de.rs
+++ b/crates/ui-egui/src/i18n/de.rs
@@ -319,6 +319,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Options|General" => "Allgemein",
         "Options|Save" => "Speichern",
         "Show formula bar" => "Bearbeitungsleiste anzeigen",
+        "Enable AutoComplete for cell values" => "AutoVervollständigen für Zellwerte aktivieren",
         "Save .xlsx workbooks automatically after every change" => ".xlsx-Arbeitsmappen nach jeder Änderung automatisch speichern",
         "Workbook calculation" => "Arbeitsmappenberechnung",
         "Enable iterative calculation" => "Iterative Berechnung aktivieren",
diff --git a/crates/ui-egui/src/i18n/es.rs b/crates/ui-egui/src/i18n/es.rs
index 6812cb4..4ce231b 100644
--- a/crates/ui-egui/src/i18n/es.rs
+++ b/crates/ui-egui/src/i18n/es.rs
@@ -318,6 +318,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Options|General" => "General",
         "Options|Save" => "Guardar",
         "Show formula bar" => "Mostrar barra de fórmulas",
+        "Enable AutoComplete for cell values" => "Habilitar Autocompletar para valores de celda",
         "Save .xlsx workbooks automatically after every change" => "Guardar automáticamente los libros .xlsx tras cada cambio",
         "Workbook calculation" => "Cálculo del libro",
         "Enable iterative calculation" => "Habilitar cálculo iterativo",
diff --git a/crates/ui-egui/src/i18n/fr.rs b/crates/ui-egui/src/i18n/fr.rs
index 34370b7..5d20ab0 100644
--- a/crates/ui-egui/src/i18n/fr.rs
+++ b/crates/ui-egui/src/i18n/fr.rs
@@ -405,6 +405,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Options|General" => "Options|Général",
         "Options|Save" => "Options|Enregistrer",
         "Show formula bar" => "Afficher la barre de formule",
+        "Enable AutoComplete for cell values" => "Activer la saisie semi-automatique des valeurs de cellule",
         "Save .xlsx workbooks automatically after every change" => "Enregistrer automatiquement les classeurs .xlsx après chaque modification",
         "Workbook calculation" => "Calcul du classeur",
         "Enable iterative calculation" => "Activer le calcul itératif",
diff --git a/crates/ui-egui/src/i18n/ko.rs b/crates/ui-egui/src/i18n/ko.rs
index 9e5a85e..1902ad3 100644
--- a/crates/ui-egui/src/i18n/ko.rs
+++ b/crates/ui-egui/src/i18n/ko.rs
@@ -405,6 +405,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Options|General" => "일반",
         "Options|Save" => "저장",
         "Show formula bar" => "수식 입력줄 표시",
+        "Enable AutoComplete for cell values" => "셀 값에 자동 완성 사용",
         "Save .xlsx workbooks automatically after every change" => "변경할 때마다 .xlsx 통합 문서를 자동으로 저장",
         "Workbook calculation" => "통합 문서 계산",
         "Enable iterative calculation" => "반복 계산 사용",
diff --git a/crates/ui-egui/src/i18n/pt.rs b/crates/ui-egui/src/i18n/pt.rs
index dcf6563..fb9236c 100644
--- a/crates/ui-egui/src/i18n/pt.rs
+++ b/crates/ui-egui/src/i18n/pt.rs
@@ -405,6 +405,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Options|General" => "Geral",
         "Options|Save" => "Salvar",
         "Show formula bar" => "Mostrar barra de fórmulas",
+        "Enable AutoComplete for cell values" => "Habilitar AutoConclusão para valores de célula",
         "Save .xlsx workbooks automatically after every change" => "Salvar pastas de trabalho .xlsx automaticamente após cada alteração",
         "Workbook calculation" => "Cálculo da pasta de trabalho",
         "Enable iterative calculation" => "Habilitar cálculo iterativo",
diff --git a/crates/ui-egui/src/i18n/ru.rs b/crates/ui-egui/src/i18n/ru.rs
index 5b7cd11..765f6bb 100644
--- a/crates/ui-egui/src/i18n/ru.rs
+++ b/crates/ui-egui/src/i18n/ru.rs
@@ -405,6 +405,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Options|General" => "Общие",
         "Options|Save" => "Сохранение",
         "Show formula bar" => "Показывать строку формул",
+        "Enable AutoComplete for cell values" => "Включить автозавершение значений ячеек",
         "Save .xlsx workbooks automatically after every change" => "Автоматически сохранять книги .xlsx после каждого изменения",
         "Workbook calculation" => "Вычисления в книге",
         "Enable iterative calculation" => "Включить итеративные вычисления",
diff --git a/crates/ui-egui/src/i18n/sr.rs b/crates/ui-egui/src/i18n/sr.rs
index fea3387..cbf18d4 100644
--- a/crates/ui-egui/src/i18n/sr.rs
+++ b/crates/ui-egui/src/i18n/sr.rs
@@ -397,6 +397,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Options|General" => "Opcije|Opšte",
         "Options|Save" => "Opcije|Sačuvaj",
         "Show formula bar" => "Prikaži traku formule",
+        "Enable AutoComplete for cell values" => "Omogući automatsko dovršavanje vrednosti ćelija",
         "Save .xlsx workbooks automatically after every change" => "Automatski sačuvaj .xlsx radne sveske posle svake izmene",
         "Workbook calculation" => "Izračunavanje radne sveske",
         "Enable iterative calculation" => "Omogući iterativno izračunavanje",
diff --git a/crates/ui-egui/src/i18n/zh.rs b/crates/ui-egui/src/i18n/zh.rs
index f30fcc9..0017592 100644
--- a/crates/ui-egui/src/i18n/zh.rs
+++ b/crates/ui-egui/src/i18n/zh.rs
@@ -397,6 +397,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Options|General" => "常规",
         "Options|Save" => "保存",
         "Show formula bar" => "显示编辑栏",
+        "Enable AutoComplete for cell values" => "为单元格值启用记忆式键入",
         "Save .xlsx workbooks automatically after every change" => "每次更改后自动保存 .xlsx 工作簿",
         "Workbook calculation" => "工作簿计算",
         "Enable iterative calculation" => "启用迭代计算",
diff --git a/crates/ui-egui/src/lib.rs b/crates/ui-egui/src/lib.rs
index be03199..f96cdac 100644
--- a/crates/ui-egui/src/lib.rs
+++ b/crates/ui-egui/src/lib.rs
@@ -57,6 +57,9 @@ pub struct UiState {
     pub status_bar: bool,
     /// Motion in the UI: the selection outline glides to a new selection (View ▸ Animations).
     pub animations: bool,
+    /// Enable AutoComplete for cell values (File ▸ Options ▸ Editing): typed text is completed
+    /// from the one matching entry in the same column.
+    pub autocomplete: bool,
     pub recent: Vec<String>,
     /// One-shot keytip request for a ribbon control: set when a keytip action resolves to
     /// [`keytips::Action::Control`], consumed (and cleared) by the control's render site.
@@ -99,6 +102,7 @@ impl Default for UiState {
             formula_bar_expanded: false,
             status_bar: true,
             animations: true,
+            autocomplete: true,
             recent: vec![],
             keytip_invoke: None,
             language: i18n::Language::En,
@@ -600,6 +604,10 @@ impl SheetApp {
                 self.ui.animations = p.get("on").and_then(Json::as_bool).unwrap_or(!self.ui.animations);
                 Ok(json!({"on": self.ui.animations}))
             }
+            "options.autoComplete" => {
+                self.ui.autocomplete = p.get("on").and_then(Json::as_bool).unwrap_or(!self.ui.autocomplete);
+                Ok(json!({"on": self.ui.autocomplete}))
+            }
             "view.interfaceScale" => {
                 // `{"percent": 125}` or `{"percent": "auto"}`; out-of-range values are clamped.
                 let percent = match p.get("percent") {
@@ -883,7 +891,7 @@ impl SheetApp {
         };
         let mut ed = editor::EditState::new(d.wb.active_sheet, at, text, replace, from_formula_bar);
         ed.locale = locale;
-        if replace && !ed.is_formula() {
+        if replace && self.ui.autocomplete && !ed.is_formula() {
             ed.completion = editor::column_completion(sh, at, &ed.text);
         }
         self.editor = Some(ed);
diff --git a/crates/ui-egui/tests/interaction.rs b/crates/ui-egui/tests/interaction.rs
index d136b46..b40769c 100644
--- a/crates/ui-egui/tests/interaction.rs
+++ b/crates/ui-egui/tests/interaction.rs
@@ -655,6 +655,98 @@ fn column_autocomplete_completes_on_enter() {
     assert_eq!(value(&h, "A5"), Value::from("Ea"));
 }
 
+fn completion(h: &egui_kittest::Harness<'static, SheetApp>) -> (String, Option<String>) {
+    let ed = h.state().editor.as_ref().expect("still editing");
+    (ed.text.clone(), ed.completion.clone())
+}
+
+#[test]
+fn column_autocomplete_backspace_and_escape_drop_only_the_proposal() {
+    let mut s = blank();
+    s.execute("range.setValues", json!({"range": "A1", "values": [["Apple"], ["Banana"]]})).unwrap();
+    s.execute("selection.set", json!({"cell": "A3"})).unwrap();
+    let mut h = harness(s);
+    text(&mut h, "ap");
+    assert_eq!(completion(&h), ("ap".into(), Some("Apple".into())), "\"ple\" is proposed after the caret");
+    key(&mut h, Key::Enter, Modifiers::NONE);
+    assert_eq!(value(&h, "A3"), Value::from("Apple"), "Enter accepts it, with the entry's own case");
+    text(&mut h, "ba");
+    key(&mut h, Key::Tab, Modifiers::NONE);
+    assert_eq!(value(&h, "A4"), Value::from("Banana"), "Tab accepts it too");
+
+    // Backspace removes the proposal, not the typed "a".
+    h.state_mut().run("selection.set", json!({"cell": "A5"})).unwrap();
+    h.run_steps(2);
+    text(&mut h, "ba");
+    key(&mut h, Key::Backspace, Modifiers::NONE);
+    assert_eq!(completion(&h), ("ba".into(), None));
+    key(&mut h, Key::Enter, Modifiers::NONE);
+    assert_eq!(value(&h, "A5"), Value::from("ba"));
+
+    // Escape dismisses the proposal and keeps the edit; a second Escape cancels it.
+    text(&mut h, "ap");
+    key(&mut h, Key::Escape, Modifiers::NONE);
+    assert_eq!(completion(&h), ("ap".into(), None));
+    key(&mut h, Key::Escape, Modifiers::NONE);
+    assert!(h.state().editor.is_none());
+    assert_eq!(value(&h, "A6"), Value::Empty);
+}
+
+#[test]
+fn column_autocomplete_skips_ambiguous_prefixes_and_numbers() {
+    let mut s = blank();
+    s.execute("range.setValues", json!({"range": "A1", "values": [["Apricot"], ["Apple"], ["12 Main St"]]})).unwrap();
+    s.execute("selection.set", json!({"cell": "A4"})).unwrap();
+    let mut h = harness(s);
+    text(&mut h, "ap");
+    assert_eq!(completion(&h), ("ap".into(), None), "Apricot and Apple both match");
+    text(&mut h, "p");
+    assert_eq!(completion(&h), ("app".into(), Some("Apple".into())), "one more letter settles it");
+    h.state_mut().cancel_edit();
+    text(&mut h, "12");
+    assert_eq!(completion(&h), ("12".into(), None), "a number is not completed");
+}
+
+#[test]
+fn column_autocomplete_folds_case_beyond_ascii() {
+    let mut s = blank();
+    s.execute("range.setValues", json!({"range": "A1", "values": [["Ébène"], ["Ébano"], ["ébano"], ["STRAẞENBAHN"]]})).unwrap();
+    s.execute("selection.set", json!({"cell": "A5"})).unwrap();
+    let mut h = harness(s);
+    text(&mut h, "éba");
+    assert_eq!(completion(&h), ("éba".into(), Some("ébano".into())), "Ébano and ébano are one entry, Ébène doesn't match");
+    h.state_mut().cancel_edit();
+    text(&mut h, "éb");
+    assert_eq!(completion(&h).1, None, "Ébène and Ébano differ past the prefix");
+    h.state_mut().cancel_edit();
+    // "ß" is two bytes, "ẞ" three: the proposed rest starts after the fifth character, not the sixth byte.
+    text(&mut h, "straß");
+    assert_eq!(completion(&h), ("straß".into(), Some("STRAẞENBAHN".into())));
+    let painted = h.output().shapes.iter().any(|c| matches!(&c.shape, egui::Shape::Text(t) if t.galley.job.text == "ENBAHN"));
+    assert!(painted, "the rest \"ENBAHN\" is drawn after the caret");
+}
+
+#[test]
+fn column_autocomplete_can_be_turned_off() {
+    assert!(gridcraft_ui_egui::UiState::default().autocomplete);
+    let old: gridcraft_ui_egui::UiState = serde_json::from_str(r#"{"dark": true}"#).unwrap();
+    assert!(old.autocomplete, "a ui.json written before the setting existed keeps it on");
+
+    let mut s = blank();
+    s.execute("range.setValues", json!({"range": "A1", "values": [["North"]]})).unwrap();
+    s.execute("selection.set", json!({"cell": "A2"})).unwrap();
+    let mut h = harness(s);
+    assert_eq!(h.state_mut().run("options.autoComplete", json!({"on": false})), Ok(json!({"on": false})));
+    assert!(h.state().dialog.is_none());
+    text(&mut h, "No");
+    assert_eq!(completion(&h), ("No".into(), None));
+    text(&mut h, "r");
+    assert_eq!(completion(&h), ("Nor".into(), None), "typing on doesn't bring it back");
+    key(&mut h, Key::Enter, Modifiers::NONE);
+    assert_eq!(value(&h, "A2"), Value::from("Nor"));
+    assert_eq!(h.state_mut().run("options.autoComplete", json!({})), Ok(json!({"on": true})), "no parameters: it toggles");
+}
+
 /// An .xlsm carrying a VBA project, saved to bytes.
 fn macro_workbook_bytes() -> Vec<u8> {
     let mut wb = gridcraft_engine::model::Workbook::new();