diff --git a/app/dao/notifications_dao.py b/app/dao/notifications_dao.py
index c289f60ed..dd23d32b5 100644
--- a/app/dao/notifications_dao.py
+++ b/app/dao/notifications_dao.py
@@ -1,13 +1,15 @@
 import uuid
+import pytz
 from datetime import (
     datetime,
     timedelta,
     date
 )
+from itertools import groupby
 
 from flask import current_app
 from werkzeug.datastructures import MultiDict
-from sqlalchemy import (desc, func, or_, and_, asc)
+from sqlalchemy import (desc, func, or_, and_, asc, cast, Text)
 from sqlalchemy.orm import joinedload
 
 from app import db
@@ -209,6 +211,30 @@ def get_notifications_for_job(service_id, job_id, filter_dict=None, page=1, page
     )
 
 
+@statsd(namespace="dao")
+def get_notification_billable_unit_count_per_month(service_id, year):
+    start, end = get_financial_year(year)
+
+    notifications = db.session.query(
+        NotificationHistory.created_at,
+        NotificationHistory.billable_units
+    ).order_by(
+        NotificationHistory.created_at
+    ).filter(
+        NotificationHistory.billable_units != 0,
+        NotificationHistory.service_id == service_id,
+        NotificationHistory.created_at >= start,
+        NotificationHistory.created_at < end
+    )
+
+    return [
+        (month, sum(count for _, count in row))
+        for month, row in groupby(
+            notifications, lambda row: get_bst_month(row[0])
+        )
+    ]
+
+
 @statsd(namespace="dao")
 def get_notification_with_personalisation(service_id, notification_id, key_type):
     filter_dict = {'service_id': service_id, 'id': notification_id}
@@ -319,3 +345,20 @@ def dao_timeout_notifications(timeout_period_in_seconds):
         update({'status': NOTIFICATION_TEMPORARY_FAILURE, 'updated_at': update_at}, synchronize_session=False)
     db.session.commit()
     return updated
+
+
+def get_financial_year(year):
+    return get_april_fools(year), get_april_fools(year + 1)
+
+
+def get_april_fools(year):
+    return datetime(
+        year, 4, 1, 0, 0, 0, 0,
+        pytz.timezone("Europe/London")
+    ).astimezone(pytz.utc)
+
+
+def get_bst_month(datetime):
+    return pytz.utc.localize(datetime).astimezone(
+        pytz.timezone("Europe/London")
+    ).strftime('%B')
diff --git a/app/service/rest.py b/app/service/rest.py
index 7aa823f80..2cc7dab90 100644
--- a/app/service/rest.py
+++ b/app/service/rest.py
@@ -310,3 +310,13 @@ def update_whitelist(service_id):
     else:
         dao_add_and_commit_whitelisted_contacts(whitelist_objs)
         return '', 204
+
+
+@service_blueprint.route('/<uuid:service_id>/billable-units')
+def get_billable_unit_count(service_id):
+    try:
+        return jsonify(notifications_dao.get_notification_billable_unit_count_per_month(
+            service_id, int(request.args.get('year'))
+        ))
+    except TypeError:
+        return jsonify(result='error', message='No valid year provided'), 400
diff --git a/tests/app/dao/test_notification_dao.py b/tests/app/dao/test_notification_dao.py
index 97885f50a..ea7779ecb 100644
--- a/tests/app/dao/test_notification_dao.py
+++ b/tests/app/dao/test_notification_dao.py
@@ -1,4 +1,5 @@
 from datetime import datetime, timedelta, date
+import pytz
 import uuid
 from functools import partial
 
@@ -31,13 +32,15 @@ from app.dao.notifications_dao import (
     delete_notifications_created_more_than_a_week_ago,
     get_notification_by_id,
     get_notification_for_job,
+    get_notification_billable_unit_count_per_month,
     get_notification_with_personalisation,
     get_notifications_for_job,
     get_notifications_for_service,
     update_notification_status_by_id,
     update_notification_status_by_reference,
     dao_delete_notifications_and_history_by_id,
-    dao_timeout_notifications)
+    dao_timeout_notifications,
+    get_financial_year)
 
 from notifications_utils.template import get_sms_fragment_count
 
@@ -685,6 +688,48 @@ def test_get_all_notifications_for_job_by_status(notify_db, notify_db_session, s
     assert len(notifications(filter_dict={'status': NOTIFICATION_STATUS_TYPES[:3]}).items) == 3
 
 
+def test_get_notification_billable_unit_count_per_month(notify_db, notify_db_session, sample_service):
+
+    for year, month, day in (
+        (2017, 1, 15),  # ↓ 2016 financial year
+        (2016, 8, 1),
+        (2016, 7, 15),
+        (2016, 4, 15),
+        (2016, 4, 15),
+        (2016, 4, 1),  # ↓ 2015 financial year
+        (2016, 3, 31),
+        (2016, 1, 15)
+    ):
+        sample_notification(
+            notify_db, notify_db_session, service=sample_service,
+            created_at=datetime(
+                year, month, day, 0, 0, 0, 0
+            ) - timedelta(hours=1, seconds=1)  # one second before midnight
+        )
+
+    for financial_year, months in (
+        (
+            2017,
+            []
+        ),
+        (
+            2016,
+            [('April', 2), ('July', 2), ('January', 1)]
+        ),
+        (
+            2015,
+            [('January', 1), ('March', 2)]
+        ),
+        (
+            2014,
+            []
+        )
+    ):
+        assert get_notification_billable_unit_count_per_month(
+            sample_service.id, financial_year
+        ) == months
+
+
 def test_update_notification(sample_notification, sample_template):
     assert sample_notification.status == 'created'
     sample_notification.status = 'failed'
@@ -1158,3 +1203,11 @@ def test_should_exclude_test_key_notifications_by_default(
 
     all_notifications = get_notifications_for_service(sample_service.id, limit_days=1, key_type=KEY_TYPE_TEST).items
     assert len(all_notifications) == 1
+
+
+def test_get_financial_year():
+    start, end = get_financial_year(2000)
+    assert start.tzinfo == pytz.utc
+    assert start.isoformat() == '2000-04-01T00:01:00+00:00'
+    assert end.tzinfo == pytz.utc
+    assert end.isoformat() == '2001-04-01T00:01:00+00:00'
diff --git a/tests/app/service/test_rest.py b/tests/app/service/test_rest.py
index 179d9383a..69e382c4e 100644
--- a/tests/app/service/test_rest.py
+++ b/tests/app/service/test_rest.py
@@ -1300,3 +1300,27 @@ def test_get_detailed_services_only_includes_todays_notifications(notify_db, not
         'email': {'delivered': 0, 'failed': 0, 'requested': 0},
         'sms': {'delivered': 0, 'failed': 0, 'requested': 2}
     }
+
+
+@freeze_time('2012-12-12T12:00:01')
+def test_get_notification_billable_unit_count(client, notify_db, notify_db_session):
+    notification = create_sample_notification(notify_db, notify_db_session)
+    response = client.get(
+        '/service/{}/billable-units?year=2012'.format(notification.service_id),
+        headers=[create_authorization_header(service_id=notification.service_id)]
+    )
+    assert response.status_code == 200
+    assert json.loads(response.get_data(as_text=True)) == {
+        'December': 1
+    }
+
+
+def test_get_notification_billable_unit_count_missing_year(client, sample_service):
+    response = client.get(
+        '/service/{}/billable-units'.format(sample_service.id),
+        headers=[create_authorization_header(service_id=sample_service.id)]
+    )
+    assert response.status_code == 400
+    assert json.loads(response.get_data(as_text=True)) == {
+        'message': 'No valid year provided', 'result': 'error'
+    }