diff --git a/crates/shepherd-hud/src/app.rs b/crates/shepherd-hud/src/app.rs
index 8793f4c..3c21ae0 100644
--- a/crates/shepherd-hud/src/app.rs
+++ b/crates/shepherd-hud/src/app.rs
@@ -296,25 +296,35 @@ fn build_hud_content(state: SharedState) -> gtk4::Box {
             }
             SessionState::Active {
                 entry_name,
-                time_remaining_secs,
+                started_at,
+                time_limit_secs,
                 paused,
                 ..
             } => {
                 app_label_clone.set_text(entry_name);
-                time_display_clone.set_remaining(*time_remaining_secs);
+                // Calculate remaining time based on elapsed time since session start
+                let remaining = time_limit_secs.map(|limit| {
+                    let elapsed = started_at.elapsed().as_secs();
+                    limit.saturating_sub(elapsed)
+                });
+                time_display_clone.set_remaining(remaining);
                 time_display_clone.set_paused(*paused);
                 warning_box_clone.set_visible(false);
             }
             SessionState::Warning {
                 entry_name,
-                time_remaining_secs,
+                warning_issued_at,
+                time_remaining_at_warning,
                 ..
             } => {
                 app_label_clone.set_text(entry_name);
-                time_display_clone.set_remaining(Some(*time_remaining_secs));
+                // Calculate remaining time based on elapsed time since warning was issued
+                let elapsed = warning_issued_at.elapsed().as_secs();
+                let remaining = time_remaining_at_warning.saturating_sub(elapsed);
+                time_display_clone.set_remaining(Some(remaining));
                 warning_label_clone.set_text(&format!(
                     "Only {} seconds remaining!",
-                    time_remaining_secs
+                    remaining
                 ));
                 warning_box_clone.set_visible(true);
             }
diff --git a/crates/shepherd-hud/src/state.rs b/crates/shepherd-hud/src/state.rs
index 9f72494..5b47951 100644
--- a/crates/shepherd-hud/src/state.rs
+++ b/crates/shepherd-hud/src/state.rs
@@ -30,7 +30,8 @@ pub enum SessionState {
         session_id: SessionId,
         entry_id: EntryId,
         entry_name: String,
-        time_remaining_secs: u64,
+        warning_issued_at: std::time::Instant,
+        time_remaining_at_warning: u64,
     },
 
     /// Session is ending
@@ -187,7 +188,8 @@ impl SharedState {
                                 session_id: session_id.clone(),
                                 entry_id: entry_id.clone(),
                                 entry_name: entry_name.clone(),
-                                time_remaining_secs: time_remaining.as_secs(),
+                                warning_issued_at: std::time::Instant::now(),
+                                time_remaining_at_warning: time_remaining.as_secs(),
                             };
                         }
                     }