diff --git a/base/src/test/mod.rs b/base/src/test/mod.rs
index bcfb400..2e41417 100644
--- a/base/src/test/mod.rs
+++ b/base/src/test/mod.rs
@@ -75,6 +75,7 @@ mod test_log;
 mod test_log10;
 mod test_mod_quotient;
 mod test_networkdays;
+mod test_now;
 mod test_percentage;
 mod test_set_functions_error_handling;
 mod test_sheet_names;
diff --git a/base/src/test/test_now.rs b/base/src/test/test_now.rs
new file mode 100644
index 0000000..b86bb99
--- /dev/null
+++ b/base/src/test/test_now.rs
@@ -0,0 +1,30 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::{mock_time, test::util::new_empty_model};
+
+// 14:44 20 Mar 2023 Berlin
+const TIMESTAMP_2023: i64 = 1679319865208;
+
+#[test]
+fn arguments() {
+    let mut model = new_empty_model();
+
+    model._set("A1", "=NOW(1)");
+    model.evaluate();
+
+    assert_eq!(
+        model._get_text("A1"),
+        "#ERROR!",
+        "NOW should not accept arguments"
+    );
+}
+
+#[test]
+fn returns_date_time() {
+    mock_time::set_mock_time(TIMESTAMP_2023);
+    let mut model = new_empty_model();
+    model._set("A1", "=NOW()");
+    model.evaluate();
+    let text = model._get_text("A1");
+    assert_eq!(text, *"20/03/2023 13:44:25");
+}
diff --git a/base/src/test/test_today.rs b/base/src/test/test_today.rs
index a3b541b..ce68d8c 100644
--- a/base/src/test/test_today.rs
+++ b/base/src/test/test_today.rs
@@ -33,7 +33,8 @@ fn now_basic_utc() {
     model.evaluate();
 
     assert_eq!(model._get_text("A1"), *"20/03/2023");
-    assert_eq!(model._get_text("A2"), *"45005.572511574");
+    // 45005.572511574
+    assert_eq!(model._get_text("A2"), *"20/03/2023 13:44:25");
 }
 
 #[test]
@@ -46,5 +47,5 @@ fn now_basic_europe_berlin() {
 
     assert_eq!(model._get_text("A1"), *"20/03/2023");
     // This is UTC + 1 hour: 45005.572511574 + 1/24
-    assert_eq!(model._get_text("A2"), *"45005.614178241");
+    assert_eq!(model._get_text("A2"), *"20/03/2023 14:44:25");
 }
diff --git a/base/src/units.rs b/base/src/units.rs
index 533f0e7..8ea49ee 100644
--- a/base/src/units.rs
+++ b/base/src/units.rs
@@ -329,6 +329,7 @@ impl Model {
             Function::Tbillyield => self.units_fn_percentage_2(args, cell),
             Function::Date => self.units_fn_dates(args, cell),
             Function::Today => self.units_fn_dates(args, cell),
+            Function::Now => self.units_fn_date_times(args, cell),
             _ => None,
         }
     }
@@ -375,4 +376,8 @@ impl Model {
         // TODO: update locale and use it here
         Some(Units::Date("dd/mm/yyyy".to_string()))
     }
+
+    fn units_fn_date_times(&self, _args: &[Node], _cell: &CellReferenceIndex) -> Option<Units> {
+        Some(Units::Date("dd/mm/yyyy hh:mm:ss".to_string()))
+    }
 }