diff --git a/app.py b/app.py
index 8a81ded..debc5a1 100644
--- a/app.py
+++ b/app.py
@@ -226,8 +226,12 @@ def results(station_crs, slug, travel_date):
         trip["eurostar_plus_price"] = es.get("plus_price")
         trip["eurostar_plus_seats"] = es.get("plus_seats")
         gwr_p = trip.get("ticket_price")
+        circle_svcs = trip.get("circle_services")
+        circle_fare = circle_svcs[0]["fare"] if circle_svcs else 0
         trip["total_price"] = (
-            gwr_p + es_price if (gwr_p is not None and es_price is not None) else None
+            gwr_p + es_price + circle_fare
+            if (gwr_p is not None and es_price is not None)
+            else None
         )
 
     # If the API returned journeys but every price is None, tickets aren't on sale yet
diff --git a/templates/results.html b/templates/results.html
index 2645e3d..4c37e33 100644
--- a/templates/results.html
+++ b/templates/results.html
@@ -181,10 +181,10 @@
           <span class="nowrap">{{ row.connection_duration }}{% if row.connection_minutes < 80 %} <span title="Tight connection">⚠️</span>{% endif %}</span>
           {% if row.circle_services %}
             {% set c = row.circle_services[0] %}
-            <br><span class="text-xs text-muted nowrap">Circle {{ c.depart }} → KX {{ c.arrive_kx }}</span>
+            <br><span class="text-xs text-muted nowrap">Circle {{ c.depart }} → KX {{ c.arrive_kx }} · £{{ "%.2f"|format(c.fare) }}</span>
             {% if row.circle_services | length > 1 %}
               {% set c2 = row.circle_services[1] %}
-              <br><span class="text-xs text-muted nowrap" style="opacity:0.7">next {{ c2.depart }} → KX {{ c2.arrive_kx }}</span>
+              <br><span class="text-xs text-muted nowrap" style="opacity:0.7">next {{ c2.depart }} → KX {{ c2.arrive_kx }} · £{{ "%.2f"|format(c2.fare) }}</span>
             {% endif %}
           {% endif %}
         </td>
diff --git a/tfl_fare.py b/tfl_fare.py
new file mode 100644
index 0000000..0d3108e
--- /dev/null
+++ b/tfl_fare.py
@@ -0,0 +1,30 @@
+"""TfL single fare calculations for journeys within Zone 1."""
+
+from datetime import datetime, time
+
+import holidays
+
+CIRCLE_LINE_PEAK = 3.10
+CIRCLE_LINE_OFF_PEAK = 3.00
+
+_ENGLAND_HOLIDAYS = holidays.country_holidays("GB", subdiv="ENG")
+
+_AM_PEAK_START = time(6, 30)
+_AM_PEAK_END = time(9, 30)
+_PM_PEAK_START = time(16, 0)
+_PM_PEAK_END = time(19, 0)
+
+
+def circle_line_fare(depart_dt: datetime) -> float:
+    """Return the TfL Circle line single fare for a given departure datetime.
+
+    Peak (£3.10): Monday–Friday (excluding public holidays),
+                  06:30–09:30 and 16:00–19:00.
+    Off-peak (£3.00): all other times, weekends, and public holidays.
+    """
+    if depart_dt.date() in _ENGLAND_HOLIDAYS or depart_dt.weekday() >= 5:
+        return CIRCLE_LINE_OFF_PEAK
+    t = depart_dt.time()
+    if _AM_PEAK_START <= t < _AM_PEAK_END or _PM_PEAK_START <= t < _PM_PEAK_END:
+        return CIRCLE_LINE_PEAK
+    return CIRCLE_LINE_OFF_PEAK
diff --git a/trip_planner.py b/trip_planner.py
index ba7948d..324a703 100644
--- a/trip_planner.py
+++ b/trip_planner.py
@@ -5,6 +5,7 @@ Combine GWR station→Paddington trains with Eurostar St Pancras→destination t
 from datetime import datetime, timedelta
 
 import circle_line
+from tfl_fare import circle_line_fare
 
 MIN_CONNECTION_MINUTES = 50
 MAX_CONNECTION_MINUTES = 110
@@ -31,7 +32,11 @@ def _circle_line_services(arrive_paddington: datetime) -> list[dict]:
     )
     services = circle_line.upcoming_services(earliest_board, count=2)
     return [
-        {"depart": dep.strftime(TIME_FMT), "arrive_kx": arr.strftime(TIME_FMT)}
+        {
+            "depart": dep.strftime(TIME_FMT),
+            "arrive_kx": arr.strftime(TIME_FMT),
+            "fare": circle_line_fare(dep),
+        }
         for dep, arr in services
     ]