diff --git a/oh_queue/slack.py b/oh_queue/slack.py
index 11ca4ba..797d1bb 100644
--- a/oh_queue/slack.py
+++ b/oh_queue/slack.py
@@ -206,8 +206,8 @@ def send_appointment_summary(app, course):
                             total=upcoming.total,
                             nonempty=upcoming.nonempty,
                             time=upcoming.start_time.strftime("%I:%M%p"),
-                            delta=(upcoming.start_time - get_current_time()).seconds
-                            // 3600,
+                            delta=round((upcoming.start_time - get_current_time()).seconds
+                            / 3600),
                         ),
                     },
                 }
diff --git a/oh_queue/static/js/components/admin_appointments_manager.js b/oh_queue/static/js/components/admin_appointments_manager.js
index cd3001f..382cc3b 100644
--- a/oh_queue/static/js/components/admin_appointments_manager.js
+++ b/oh_queue/static/js/components/admin_appointments_manager.js
@@ -61,8 +61,11 @@ function AdminAppointmentsManager({ state }) {
                 <tr>
                     <td>
                         <p>
-                            How many appointments should a student have be pending simultaneously?
+                        How many appointments should a student have be pending simultaneously?
                         </p>
+                            (by 
+                            <ConfigLinkedToggle config={state.config} configKey="appointment_or_minutes" onText="minutes" offText="number"/> 
+                            )
                     </td>
                     <td className="col-md-3">
                         <ConfigLinkedNumeric
diff --git a/oh_queue/views.py b/oh_queue/views.py
index 4dc92e7..0701526 100644
--- a/oh_queue/views.py
+++ b/oh_queue/views.py
@@ -319,6 +319,12 @@ def init_config():
         public=True,
         course=get_course(),
     ))
+    db.session.add(ConfigEntry(
+        key='appointment_or_minutes',
+        value='false',
+        public=True,
+        course=get_course(),
+    ))
     db.session.add(ConfigEntry(
         key='show_okpy_backups',
         value='false',
@@ -922,6 +928,7 @@ def assign_appointment(data):
         daily_threshold = int(ConfigEntry.query.filter_by(key="daily_appointment_limit", course=get_course()).one().value)
         weekly_threshold = int(ConfigEntry.query.filter_by(key="weekly_appointment_limit", course=get_course()).one().value)
         pending_threshold = int(ConfigEntry.query.filter_by(key="simul_appointment_limit", course=get_course()).one().value)
+        pending_metric= ConfigEntry.query.filter_by(key="appointment_or_minutes", course=get_course()).one().value
 
         start = appointment.start_time.replace(hour=0, minute=0, second=0, microsecond=0)
         week_start = start - datetime.timedelta(days=appointment.start_time.weekday())
@@ -940,13 +947,21 @@ def assign_appointment(data):
         ).count()
         if num_today >= daily_threshold:
             return socket_error("You have already signed up for {} OH slots for the same day".format(daily_threshold))
-
         num_pending = AppointmentSignup.query.join(AppointmentSignup.appointment).filter(
             Appointment.status == AppointmentStatus.pending,
             AppointmentSignup.user_id == current_user.id,
-        ).count()
-        if num_pending >= pending_threshold:
-            return socket_error("You have already signed up for {} OH slots that have not yet occurred.".format(pending_threshold))
+        )
+        if pending_metric != 'false':
+            start = appointment.duration
+            num_pend = [appt.appointment.duration for appt in list(num_pending)]
+            threshold  = datetime.timedelta(minutes=pending_threshold)
+            for item in num_pend:
+                start += item
+            if start > threshold:
+                return socket_error("You cannot sign up for more than {} minutes of OH that have not yet occurred.".format(pending_threshold))
+        else:
+            if num_pending.count() >= pending_threshold:
+                return socket_error("You have already signed up for {} OH slots that have not yet occurred.".format(pending_threshold))
 
     old_signup = AppointmentSignup.query.filter_by(
         appointment_id=data["appointment_id"],