diff --git a/lib/livebook/session/data.ex b/lib/livebook/session/data.ex
index f476d4a8b..2883b2d40 100644
--- a/lib/livebook/session/data.ex
+++ b/lib/livebook/session/data.ex
@@ -52,7 +52,8 @@ defmodule Livebook.Session.Data do
           revision: cell_revision(),
           deltas: list(Delta.t()),
           revision_by_client_pid: %{pid() => cell_revision()},
-          evaluated_at: DateTime.t()
+          digest: String.t(),
+          evaluation_digest: String.t() | nil
         }
 
   @type cell_revision :: non_neg_integer()
@@ -125,7 +126,7 @@ defmodule Livebook.Session.Data do
     for section <- notebook.sections,
         cell <- section.cells,
         into: %{},
-        do: {cell.id, new_cell_info([])}
+        do: {cell.id, new_cell_info(cell, [])}
   end
 
   @doc """
@@ -415,7 +416,7 @@ defmodule Livebook.Session.Data do
     data_actions
     |> set!(
       notebook: Notebook.insert_cell(data.notebook, section_id, index, cell),
-      cell_infos: Map.put(data.cell_infos, cell.id, new_cell_info(data.client_pids))
+      cell_infos: Map.put(data.cell_infos, cell.id, new_cell_info(cell, data.client_pids))
     )
   end
 
@@ -512,8 +513,7 @@ defmodule Livebook.Session.Data do
     data_actions
     |> set_cell_info!(cell.id,
       validity_status: :evaluated,
-      evaluation_status: :ready,
-      evaluated_at: DateTime.utc_now()
+      evaluation_status: :ready
     )
     |> set_section_info!(section.id, evaluating_cell_id: nil)
   end
@@ -553,7 +553,9 @@ defmodule Livebook.Session.Data do
 
             data_actions
             |> set!(notebook: Notebook.update_cell(data.notebook, id, &%{&1 | outputs: []}))
-            |> set_cell_info!(id, evaluation_status: :evaluating)
+            |> update_cell_info!(id, fn info ->
+              %{info | evaluation_status: :evaluating, evaluation_digest: info.digest}
+            end)
             |> set_section_info!(section.id, evaluating_cell_id: id, evaluation_queue: ids)
             |> add_action({:start_evaluation, cell, section})
 
@@ -575,7 +577,11 @@ defmodule Livebook.Session.Data do
     |> set_section_info!(section.id, evaluating_cell_id: nil, evaluation_queue: [])
     |> reduce(
       section.cells,
-      &set_cell_info!(&1, &2.id, validity_status: :fresh, evaluation_status: :ready)
+      &set_cell_info!(&1, &2.id,
+        validity_status: :fresh,
+        evaluation_status: :ready,
+        evaluation_digest: nil
+      )
     )
   end
 
@@ -651,10 +657,18 @@ defmodule Livebook.Session.Data do
 
     new_source = JSInterop.apply_delta_to_string(transformed_new_delta, cell.source)
 
+    new_digest = compute_digest(new_source)
+
     data_actions
     |> set!(notebook: Notebook.update_cell(data.notebook, cell.id, &%{&1 | source: new_source}))
     |> update_cell_info!(cell.id, fn info ->
-      info = %{info | deltas: info.deltas ++ [transformed_new_delta], revision: info.revision + 1}
+      info = %{
+        info
+        | deltas: info.deltas ++ [transformed_new_delta],
+          revision: info.revision + 1,
+          digest: new_digest
+      }
+
       # Before receiving acknowledgement, the client receives all the other deltas,
       # so we can assume they are in sync with the server and have the same revision.
       info = put_in(info.revision_by_client_pid[client_pid], info.revision)
@@ -709,14 +723,15 @@ defmodule Livebook.Session.Data do
     }
   end
 
-  defp new_cell_info(client_pids) do
+  defp new_cell_info(cell, client_pids) do
     %{
       revision: 0,
       deltas: [],
       revision_by_client_pid: Map.new(client_pids, &{&1, 0}),
       validity_status: :fresh,
       evaluation_status: :ready,
-      evaluated_at: nil
+      digest: compute_digest(cell.source),
+      evaluation_digest: nil
     }
   end
 
@@ -770,6 +785,8 @@ defmodule Livebook.Session.Data do
     set!(data_actions, dirty: dirty)
   end
 
+  defp compute_digest(source), do: :erlang.md5(source)
+
   @doc """
   Finds the cell that's currently being evaluated in the given section.
   """
diff --git a/lib/livebook_web/live/cell_component.ex b/lib/livebook_web/live/cell_component.ex
index 22a6cdf0e..7b69d0c75 100644
--- a/lib/livebook_web/live/cell_component.ex
+++ b/lib/livebook_web/live/cell_component.ex
@@ -249,55 +249,53 @@ defmodule LivebookWeb.CellComponent do
     |> String.split("\n")
   end
 
-  defp render_cell_status(%{evaluation_status: :evaluating}) do
-    assigns = %{}
-
-    ~L"""
-    <div class="flex items-center space-x-2">
-      <div class="text-xs text-gray-400">Evaluating</div>
-      <span class="flex relative h-3 w-3">
-        <span class="animate-ping absolute inline-flex h-3 w-3 rounded-full bg-blue-400 opacity-75"></span>
-        <span class="relative inline-flex rounded-full h-3 w-3 bg-blue-500"></span>
-      </span>
-    </div>
-    """
+  defp render_cell_status(%{evaluation_status: :evaluating} = info) do
+    render_status_indicator(
+      "Evaluating",
+      "bg-blue-500",
+      "bg-blue-400",
+      info.digest != info.evaluation_digest
+    )
   end
 
   defp render_cell_status(%{evaluation_status: :queued}) do
-    assigns = %{}
+    render_status_indicator("Queued", "bg-gray-500", "bg-gray-400", false)
+  end
+
+  defp render_cell_status(%{validity_status: :evaluated} = info) do
+    render_status_indicator(
+      "Evaluated",
+      "bg-green-400",
+      nil,
+      info.digest != info.evaluation_digest
+    )
+  end
+
+  defp render_cell_status(%{validity_status: :stale} = info) do
+    render_status_indicator("Stale", "bg-yellow-200", nil, info.digest != info.evaluation_digest)
+  end
+
+  defp render_cell_status(_), do: nil
+
+  defp render_status_indicator(text, circle_class, animated_circle_class, show_changed) do
+    assigns = %{
+      text: text,
+      circle_class: circle_class,
+      animated_circle_class: animated_circle_class,
+      show_changed: show_changed
+    }
 
     ~L"""
-    <div class="flex items-center space-x-2">
-      <div class="text-xs text-gray-400">Queued</div>
+    <div class="flex items-center space-x-1">
+      <div class="flex text-xs text-gray-400">
+        <%= @text %>
+        <span class="<%= unless(@show_changed, do: "invisible") %>">*</span>
+      </div>
       <span class="flex relative h-3 w-3">
-        <span class="animate-ping absolute inline-flex h-3 w-3 rounded-full bg-gray-400 opacity-75"></span>
-        <span class="relative inline-flex rounded-full h-3 w-3 bg-gray-500"></span>
+        <span class="animate-ping absolute inline-flex h-3 w-3 rounded-full <%= @animated_circle_class %> opacity-75"></span>
+        <span class="relative inline-flex rounded-full h-3 w-3 <%= @circle_class %>"></span>
       </span>
     </div>
     """
   end
-
-  defp render_cell_status(%{validity_status: :evaluated}) do
-    assigns = %{}
-
-    ~L"""
-    <div class="flex items-center space-x-2">
-      <div class="text-xs text-gray-400">Evaluated</div>
-      <div class="h-3 w-3 rounded-full bg-green-400"></div>
-    </div>
-    """
-  end
-
-  defp render_cell_status(%{validity_status: :stale}) do
-    assigns = %{}
-
-    ~L"""
-    <div class="flex items-center space-x-2">
-      <div class="text-xs text-gray-400">Stale</div>
-      <div class="h-3 w-3 rounded-full bg-yellow-200"></div>
-    </div>
-    """
-  end
-
-  defp render_cell_status(_), do: nil
 end
diff --git a/test/livebook/session/data_test.exs b/test/livebook/session/data_test.exs
index 2512f5186..c93edf9f6 100644
--- a/test/livebook/session/data_test.exs
+++ b/test/livebook/session/data_test.exs
@@ -665,6 +665,32 @@ defmodule Livebook.Session.DataTest do
               }, []} = Data.apply_operation(data, operation)
     end
 
+    test "updates cell evaluation digest" do
+      data =
+        data_after_operations!([
+          {:insert_section, self(), 0, "s1"},
+          {:insert_cell, self(), "s1", 0, :elixir, "c1"},
+          {:insert_cell, self(), "s1", 1, :elixir, "c2"},
+          {:queue_cell_evaluation, self(), "c1"}
+        ])
+
+      %{cell_infos: %{"c1" => %{digest: digest}}} = data
+
+      operation = {:add_cell_evaluation_response, self(), "c1", {:ok, [1, 2, 3]}}
+
+      assert {:ok,
+              %{
+                cell_infos: %{
+                  "c1" => %{
+                    validity_status: :evaluated,
+                    evaluation_status: :ready,
+                    evaluation_digest: ^digest
+                  }
+                },
+                section_infos: %{"s1" => %{evaluating_cell_id: nil, evaluation_queue: []}}
+              }, []} = Data.apply_operation(data, operation)
+    end
+
     test "marks next queued cell in this section as evaluating if there is one" do
       data =
         data_after_operations!([
@@ -1048,6 +1074,25 @@ defmodule Livebook.Session.DataTest do
               }, _actions} = Data.apply_operation(data, operation)
     end
 
+    test "updates cell digest based on the new content" do
+      data =
+        data_after_operations!([
+          {:client_join, self()},
+          {:insert_section, self(), 0, "s1"},
+          {:insert_cell, self(), "s1", 0, :elixir, "c1"}
+        ])
+
+      %{cell_infos: %{"c1" => %{digest: digest}}} = data
+
+      delta = Delta.new() |> Delta.insert("cats")
+      operation = {:apply_cell_delta, self(), "c1", delta, 1}
+
+      assert {:ok, %{cell_infos: %{"c1" => %{digest: new_digest}}}, _actions} =
+               Data.apply_operation(data, operation)
+
+      assert digest != new_digest
+    end
+
     test "transforms the delta if the revision is not the most recent" do
       client1_pid = IEx.Helpers.pid(0, 0, 0)
       client2_pid = IEx.Helpers.pid(0, 0, 1)