diff --git a/khata/web/helpers.py b/khata/web/helpers.py
index cb42dd1..578609b 100644
--- a/khata/web/helpers.py
+++ b/khata/web/helpers.py
@@ -79,7 +79,11 @@ def shift_day(d: date, delta: int) -> date:
     return d + timedelta(days=delta)
 
 
-# Indian weekly expiry days: NIFTY (NFO) weekly = Thursday (3 in Python weekday).
-# BSE/Sensex weekly = Tuesday (1). We mark both.
-def is_expiry_day(d: date) -> bool:
-    return d.weekday() in (1, 3)
+# Retained for compatibility — the web UI now derives expiry days from the
+# user's own trade history (see queries.expiry_days_in_range). This helper
+# defaults to False so templates without an `expiry_days` set don't light up
+# days that aren't actually expiries.
+def is_expiry_day(d: date, expiry_days: frozenset[date] | None = None) -> bool:
+    if expiry_days is None:
+        return False
+    return d in expiry_days
diff --git a/khata/web/main.py b/khata/web/main.py
index 598ca6d..84fe495 100644
--- a/khata/web/main.py
+++ b/khata/web/main.py
@@ -26,7 +26,6 @@
 TEMPLATES.env.globals.update(
     fmt_rupees=fmt_rupees,
     paise_to_rupees=paise_to_rupees,
-    is_expiry_day=H.is_expiry_day,
     month_name=H.month_name,
     fmt_time_ist=H.fmt_time_ist,
     today_iso=lambda: H.today_ist().isoformat(),
@@ -70,6 +69,9 @@ def calendar_view(
         grid = H.month_grid(year, month)
         prev_y, prev_m = H.prev_month(year, month)
         next_y, next_m = H.next_month(year, month)
+        expiry_days = Q.expiry_days_in_range(
+            conn, user_id, date(year, month, 1), date(next_y, next_m, 1)
+        )
 
         # Month totals
         total_net = sum((d.get("net_paise") or 0) for d in summary.values())
@@ -84,6 +86,7 @@ def calendar_view(
                 "month": month,
                 "grid": grid,
                 "summary": summary,
+                "expiry_days": expiry_days,
                 "prev_y": prev_y,
                 "prev_m": prev_m,
                 "next_y": next_y,
@@ -109,6 +112,8 @@ def day_view(
         trades = Q.trades_on_day(conn, user_id, d)
         totals = Q.day_totals(trades)
         note = Q.get_daily_note(conn, user_id, d)
+        # `d` counts as an expiry day if any trade in the user's book expires on it.
+        expiry_days = Q.expiry_days_in_range(conn, user_id, d, H.shift_day(d, 1))
         return TEMPLATES.TemplateResponse(
             request,
             "day.html",
@@ -120,7 +125,7 @@ def day_view(
                 "totals": totals,
                 "note": note,
                 "endpoint": f"/notes/day/{d.isoformat()}",
-                "is_expiry": H.is_expiry_day(d),
+                "is_expiry": d in expiry_days,
             },
         )
 
diff --git a/khata/web/queries.py b/khata/web/queries.py
index 2a09a94..f1464d5 100644
--- a/khata/web/queries.py
+++ b/khata/web/queries.py
@@ -8,6 +8,35 @@
 
 
 # ── calendar ───────────────────────────────────────────────────────────
+def expiry_days_in_range(
+    conn: sqlite3.Connection, user_id: int, start: date, end_excl: date
+) -> frozenset[date]:
+    """Distinct `trades.expiry` values falling inside [start, end_excl).
+
+    Used to mark calendar days the user actually had an expiring contract on,
+    rather than hardcoding Tue/Thu. Empty set if the user has no derivative
+    trades or no data yet.
+    """
+    rows = conn.execute(
+        """
+        SELECT DISTINCT expiry
+        FROM trades
+        WHERE user_id = ?
+          AND expiry IS NOT NULL
+          AND expiry >= ?
+          AND expiry < ?
+        """,
+        (user_id, start.isoformat(), end_excl.isoformat()),
+    ).fetchall()
+    out: set[date] = set()
+    for r in rows:
+        try:
+            out.add(date.fromisoformat(r["expiry"]))
+        except (TypeError, ValueError):
+            continue
+    return frozenset(out)
+
+
 def month_summary_by_day(
     conn: sqlite3.Connection, user_id: int, year: int, month: int
 ) -> dict[str, dict[str, Any]]:
diff --git a/khata/web/templates/calendar.html b/khata/web/templates/calendar.html
index a00f62e..9bf475f 100644
--- a/khata/web/templates/calendar.html
+++ b/khata/web/templates/calendar.html
@@ -35,10 +35,10 @@ <h1>{{ month_name(month) }} {{ year }}</h1>
           {% set iso = d.isoformat() %}
           {% set s = summary.get(iso) %}
           {% set net = s.net_paise if s else 0 %}
-          <a class="day {% if d == today %}day-today{% endif %} {% if s %}{% if net > 0 %}day-win{% elif net < 0 %}day-loss{% else %}day-neutral{% endif %}{% endif %} {% if is_expiry_day(d) %}day-expiry{% endif %}"
+          <a class="day {% if d == today %}day-today{% endif %} {% if s %}{% if net > 0 %}day-win{% elif net < 0 %}day-loss{% else %}day-neutral{% endif %}{% endif %} {% if d in expiry_days %}day-expiry{% endif %}"
              href="/day/{{ iso }}">
             <span class="day-num">{{ d.day }}</span>
-            {% if is_expiry_day(d) %}<span class="expiry-dot" title="weekly expiry">•</span>{% endif %}
+            {% if d in expiry_days %}<span class="expiry-dot" title="expiry day">•</span>{% endif %}
             {% if s %}
               <span class="day-pnl">{{ fmt_rupees(net) }}</span>
               <span class="day-count">{{ s.n }} trade{{ '' if s.n == 1 else 's' }}</span>
@@ -52,7 +52,7 @@ <h1>{{ month_name(month) }} {{ year }}</h1>
   <footer class="legend">
     <span class="swatch swatch-win"></span> win day
     <span class="swatch swatch-loss"></span> loss day
-    <span class="swatch swatch-expiry"></span> weekly expiry (Tue/Thu)
+    <span class="swatch swatch-expiry"></span> expiry of a contract you traded
   </footer>
 </section>
 {% endblock %}