diff --git a/base/src/test/user_model/mod.rs b/base/src/test/user_model/mod.rs
index 646abfc..d995372 100644
--- a/base/src/test/user_model/mod.rs
+++ b/base/src/test/user_model/mod.rs
@@ -1,4 +1,5 @@
 mod test_add_delete_sheets;
+mod test_autofill;
 mod test_clear_cells;
 mod test_diff_queue;
 mod test_evaluation;
diff --git a/base/src/test/user_model/test_autofill.rs b/base/src/test/user_model/test_autofill.rs
new file mode 100644
index 0000000..d345dea
--- /dev/null
+++ b/base/src/test/user_model/test_autofill.rs
@@ -0,0 +1,399 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::constants::{LAST_COLUMN, LAST_ROW};
+use crate::expressions::types::Area;
+use crate::test::util::new_empty_model;
+use crate::UserModel;
+
+#[test]
+fn basic_tests() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // This is cell A3
+    model.set_user_input(0, 3, 1, "alpha").unwrap();
+    // We autofill from A3 to A5
+    model
+        .auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 3,
+                column: 1,
+                width: 1,
+                height: 1,
+            },
+            5,
+        )
+        .unwrap();
+    assert_eq!(
+        model.get_formatted_cell_value(0, 4, 1),
+        Ok("alpha".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 5, 1),
+        Ok("alpha".to_string())
+    );
+}
+
+#[test]
+fn one_cell_down() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.set_user_input(0, 1, 1, "23").unwrap();
+    model
+        .auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 1,
+                width: 1,
+                height: 1,
+            },
+            2,
+        )
+        .unwrap();
+    assert_eq!(
+        model.get_formatted_cell_value(0, 2, 1),
+        Ok("23".to_string())
+    );
+}
+
+#[test]
+fn alpha_beta_gamma() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // cells A1:B3
+    model.set_user_input(0, 1, 1, "Alpher").unwrap();
+    model.set_user_input(0, 2, 1, "Bethe").unwrap();
+    model.set_user_input(0, 3, 1, "Gamow").unwrap();
+    model.set_user_input(0, 1, 2, "=A1").unwrap();
+    model.set_user_input(0, 2, 2, "=A2").unwrap();
+    model.set_user_input(0, 3, 2, "=A3").unwrap();
+    // We autofill from A1:B3 to A9
+    model
+        .auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 1,
+                width: 2,
+                height: 3,
+            },
+            9,
+        )
+        .unwrap();
+
+    assert_eq!(
+        model.get_formatted_cell_value(0, 4, 1),
+        Ok("Alpher".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 5, 1),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 6, 1),
+        Ok("Gamow".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 7, 1),
+        Ok("Alpher".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 8, 1),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 9, 1),
+        Ok("Gamow".to_string())
+    );
+
+    assert_eq!(
+        model.get_formatted_cell_value(0, 4, 2),
+        Ok("Alpher".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 5, 2),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 6, 2),
+        Ok("Gamow".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 7, 2),
+        Ok("Alpher".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 8, 2),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 9, 2),
+        Ok("Gamow".to_string())
+    );
+
+    assert_eq!(model.get_cell_content(0, 4, 2), Ok("=A4".to_string()));
+}
+
+#[test]
+fn styles() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // cells A1:B3
+    model.set_user_input(0, 1, 1, "Alpher").unwrap();
+    model.set_user_input(0, 2, 1, "Bethe").unwrap();
+    model.set_user_input(0, 3, 1, "Gamow").unwrap();
+
+    let a2 = Area {
+        sheet: 0,
+        row: 2,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+
+    let a3 = Area {
+        sheet: 0,
+        row: 3,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+
+    model.update_range_style(&a2, "font.i", "true").unwrap();
+    model
+        .update_range_style(&a3, "fill.bg_color", "#334455")
+        .unwrap();
+
+    model
+        .auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 1,
+                width: 1,
+                height: 3,
+            },
+            9,
+        )
+        .unwrap();
+
+    // Check that cell A5 has A2 style
+    let style = model.get_cell_style(0, 5, 1).unwrap();
+    assert!(style.font.i);
+    // A6 would have the style of A3
+    let style = model.get_cell_style(0, 6, 1).unwrap();
+    assert_eq!(style.fill.bg_color, Some("#334455".to_string()));
+
+    model.undo().unwrap();
+
+    assert_eq!(model.get_cell_content(0, 4, 1), Ok("".to_string()));
+    // Check that cell A5 has A2 style
+    let style = model.get_cell_style(0, 5, 1).unwrap();
+    assert!(!style.font.i);
+    // A6 would have the style of A3
+    let style = model.get_cell_style(0, 6, 1).unwrap();
+    assert_eq!(style.fill.bg_color, None);
+
+    model.redo().unwrap();
+    assert_eq!(
+        model.get_formatted_cell_value(0, 4, 1),
+        Ok("Alpher".to_string())
+    );
+    // Check that cell A5 has A2 style
+    let style = model.get_cell_style(0, 5, 1).unwrap();
+    assert!(style.font.i);
+    // A6 would have the style of A3
+    let style = model.get_cell_style(0, 6, 1).unwrap();
+    assert_eq!(style.fill.bg_color, Some("#334455".to_string()));
+}
+
+#[test]
+fn upwards() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // cells A10:A12
+    model.set_user_input(0, 10, 1, "Alpher").unwrap();
+    model.set_user_input(0, 11, 1, "Bethe").unwrap();
+    model.set_user_input(0, 12, 1, "Gamow").unwrap();
+
+    // We fill upwards to row 5
+    model
+        .auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 10,
+                column: 1,
+                width: 1,
+                height: 3,
+            },
+            5,
+        )
+        .unwrap();
+
+    assert_eq!(
+        model.get_formatted_cell_value(0, 9, 1),
+        Ok("Gamow".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 8, 1),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 7, 1),
+        Ok("Alpher".to_string())
+    );
+}
+
+#[test]
+fn upwards_4() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // cells A10:A13
+    model.set_user_input(0, 10, 1, "Margaret Burbidge").unwrap();
+    model.set_user_input(0, 11, 1, "Geoffrey Burbidge").unwrap();
+    model.set_user_input(0, 12, 1, "Willy Fowler").unwrap();
+    model.set_user_input(0, 13, 1, "Fred Hoyle").unwrap();
+
+    // We fill upwards to row 5
+    model
+        .auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 10,
+                column: 1,
+                width: 1,
+                height: 4,
+            },
+            5,
+        )
+        .unwrap();
+
+    assert_eq!(
+        model.get_formatted_cell_value(0, 9, 1),
+        Ok("Fred Hoyle".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 8, 1),
+        Ok("Willy Fowler".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 5, 1),
+        Ok("Fred Hoyle".to_string())
+    );
+}
+
+#[test]
+fn errors() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // cells A10:A13
+    model.set_user_input(0, 4, 1, "Margaret Burbidge").unwrap();
+
+    // Invalid sheet
+    assert_eq!(
+        model.auto_fill_rows(
+            &Area {
+                sheet: 3,
+                row: 4,
+                column: 1,
+                width: 1,
+                height: 1,
+            },
+            10,
+        ),
+        Err("Invalid worksheet index: '3'".to_string())
+    );
+
+    // invalid row
+    assert_eq!(
+        model.auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: -1,
+                column: 1,
+                width: 1,
+                height: 1,
+            },
+            10,
+        ),
+        Err("Invalid row: '-1'".to_string())
+    );
+
+    // invalid row
+    assert_eq!(
+        model.auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: LAST_ROW - 1,
+                column: 1,
+                width: 1,
+                height: 10,
+            },
+            10,
+        ),
+        Err("Invalid row: '1048584'".to_string())
+    );
+
+    assert_eq!(
+        model.auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: LAST_COLUMN + 1,
+                width: 1,
+                height: 10,
+            },
+            10,
+        ),
+        Err("Invalid column: '16385'".to_string())
+    );
+
+    assert_eq!(
+        model.auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: LAST_COLUMN - 2,
+                width: 10,
+                height: 1,
+            },
+            10,
+        ),
+        Err("Invalid column: '16391'".to_string())
+    );
+
+    assert_eq!(
+        model.auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 5,
+                column: 1,
+                width: 1,
+                height: 10,
+            },
+            -10,
+        ),
+        Err("Invalid row: '-10'".to_string())
+    );
+}
+
+#[test]
+fn invalid_parameters() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.set_user_input(0, 1, 1, "23").unwrap();
+    assert_eq!(
+        model.auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 1,
+                width: 1,
+                height: 2,
+            },
+            2,
+        ),
+        Err("Invalid parameters for autofill".to_string())
+    );
+}
diff --git a/base/src/user_model.rs b/base/src/user_model.rs
index 7fb7bbb..7320a18 100644
--- a/base/src/user_model.rs
+++ b/base/src/user_model.rs
@@ -927,7 +927,7 @@ impl UserModel {
                     column,
                     old_value: Box::new(old_value),
                     new_value: Box::new(style),
-                })
+                });
             }
         }
         self.push_diff_list(diff_list);
@@ -943,6 +943,107 @@ impl UserModel {
         Ok(self.model.get_style_for_cell(sheet, row, column))
     }
 
+    /// Fills the cells from `source_area` until `to_row`.
+    /// This simulates the user clicking on the cell outline handle and dragging it downwards (or upwards)
+    pub fn auto_fill_rows(&mut self, source_area: &Area, to_row: i32) -> Result<(), String> {
+        let mut diff_list = Vec::new();
+        let sheet = source_area.sheet;
+        let row1 = source_area.row;
+        let column1 = source_area.column;
+        let width1 = source_area.width;
+        let height1 = source_area.height;
+
+        // Check first all parameters are valid
+        if self.model.workbook.worksheet(sheet).is_err() {
+            return Err(format!("Invalid worksheet index: '{sheet}'"));
+        }
+
+        if !is_valid_column_number(column1) {
+            return Err(format!("Invalid column: '{column1}'"));
+        }
+        if !is_valid_row(row1) {
+            return Err(format!("Invalid row: '{row1}'"));
+        }
+        if !is_valid_column_number(column1 + width1 - 1) {
+            return Err(format!("Invalid column: '{}'", column1 + width1 - 1));
+        }
+        if !is_valid_row(row1 + height1 - 1) {
+            return Err(format!("Invalid row: '{}'", row1 + height1 - 1));
+        }
+
+        if !is_valid_row(to_row) {
+            return Err(format!("Invalid row: '{to_row}'"));
+        }
+
+        // anchor_row is the first row that repeats in each case.
+        let anchor_row;
+        let sign;
+        // this is the range of rows we are going to fill
+        let row_range: Vec<i32>;
+
+        if to_row >= row1 + height1 {
+            // we go downwards, we start from `row1 + height1` to `to_row`,
+            anchor_row = row1;
+            sign = 1;
+            row_range = (row1 + height1..to_row + 1).collect();
+        } else if to_row < row1 {
+            // we go upwards, starting from `row1 - `` all the way to `to_row`
+            anchor_row = row1 + height1 - 1;
+            sign = -1;
+            row_range = (to_row..row1).rev().collect();
+        } else {
+            return Err("Invalid parameters for autofill".to_string());
+        }
+
+        for column in column1..column1 + width1 {
+            let mut index = 0;
+            for row_ref in &row_range {
+                // Save value and style first
+                let row = *row_ref;
+                let old_value = self
+                    .model
+                    .workbook
+                    .worksheet(sheet)?
+                    .cell(row, column)
+                    .cloned();
+                let old_style = self.model.get_style_for_cell(sheet, row, column);
+
+                // compute the new value and set it
+                let source_row = anchor_row + index;
+                let target_value = self
+                    .model
+                    .extend_to(sheet, source_row, column, row, column)?;
+                self.model
+                    .set_user_input(sheet, row, column, target_value.to_string());
+
+                // Compute the new style and set it
+                let new_style = self.model.get_style_for_cell(sheet, source_row, column);
+                self.model.set_cell_style(sheet, row, column, &new_style)?;
+
+                // Add the diffs
+                diff_list.push(Diff::SetCellStyle {
+                    sheet,
+                    row,
+                    column,
+                    old_value: Box::new(old_style),
+                    new_value: Box::new(new_style),
+                });
+                diff_list.push(Diff::SetCellValue {
+                    sheet,
+                    row,
+                    column,
+                    new_value: target_value.to_string(),
+                    old_value: Box::new(old_value),
+                });
+
+                index = (index + sign) % height1;
+            }
+        }
+        self.push_diff_list(diff_list);
+        self.evaluate();
+        Ok(())
+    }
+
     /// Returns information about the sheets
     ///
     /// See also:
@@ -1028,7 +1129,7 @@ impl UserModel {
         if !is_valid_column_number(column) {
             return Err(format!("Invalid column: '{column}'"));
         }
-        if !is_valid_column_number(row) {
+        if !is_valid_row(row) {
             return Err(format!("Invalid row: '{row}'"));
         }
         if self.model.workbook.worksheet(sheet).is_err() {
diff --git a/bindings/wasm/src/lib.rs b/bindings/wasm/src/lib.rs
index 0af5018..72832dc 100644
--- a/bindings/wasm/src/lib.rs
+++ b/bindings/wasm/src/lib.rs
@@ -354,4 +354,13 @@ impl Model {
     pub fn get_show_grid_lines(&mut self, sheet: u32) -> Result<bool, JsError> {
         self.model.get_show_grid_lines(sheet).map_err(to_js_error)
     }
+
+    #[wasm_bindgen(js_name = "autoFillRows")]
+    pub fn auto_fill_rows(&mut self, source_area: JsValue, to_row: i32) -> Result<(), JsError> {
+        let area: Area =
+            serde_wasm_bindgen::from_value(source_area).map_err(|e| to_js_error(e.to_string()))?;
+        self.model
+            .auto_fill_rows(&area, to_row)
+            .map_err(to_js_error)
+    }
 }
diff --git a/bindings/wasm/tests/test.mjs b/bindings/wasm/tests/test.mjs
index ab31c81..5b32dfc 100644
--- a/bindings/wasm/tests/test.mjs
+++ b/bindings/wasm/tests/test.mjs
@@ -119,5 +119,14 @@ test("floating column numbers get truncated", () => {
     assert.strictEqual(model.getRowHeight(0, 5), 100.5);
 });
 
+test("autofill", () => {
+    const model = new Model('en', 'UTC');
+    model.setUserInput(0, 1, 1, "23");
+    model.autoFillRows({sheet: 0, row: 1, column: 1, width: 1, height: 1}, 2);
+
+    const result = model.getFormattedCellValue(0, 2, 1);
+    assert.strictEqual(result, "23");
+});
+