diff --git a/app/main/forms.py b/app/main/forms.py
index 5b5273b99..b6a5aaf38 100644
--- a/app/main/forms.py
+++ b/app/main/forms.py
@@ -246,6 +246,15 @@ class OrganisationTypeForm(Form):
     organisation_type = organisation_type()
 
 
+class FreeSMSAllowance(Form):
+    free_sms_allowance = IntegerField(
+        'Numbers of text message fragments per year',
+        validators=[
+            DataRequired(message='Can’t be empty')
+        ]
+    )
+
+
 class ConfirmPasswordForm(Form):
     def __init__(self, validate_password_func, *args, **kwargs):
         self.validate_password_func = validate_password_func
diff --git a/app/main/views/service_settings.py b/app/main/views/service_settings.py
index c4c788920..1dbe5ba0f 100644
--- a/app/main/views/service_settings.py
+++ b/app/main/views/service_settings.py
@@ -35,6 +35,7 @@ from app.main.forms import (
     ServiceInboundApiForm,
     InternationalSMSForm,
     OrganisationTypeForm,
+    FreeSMSAllowance,
 )
 from app import user_api_client, current_service, organisations_client, inbound_number_client
 from notifications_utils.formatters import formatted_list
@@ -589,14 +590,32 @@ def set_organisation_type(service_id):
         )
         return redirect(url_for('.service_settings', service_id=service_id))
 
-    form.organisation_type.data = current_service.get('organisation_type')
-
     return render_template(
         'views/service-settings/set-organisation-type.html',
         form=form,
     )
 
 
+@main.route("/services/<service_id>/service-settings/set-free-sms-allowance", methods=['GET', 'POST'])
+@login_required
+@user_has_permissions(admin_override=True)
+def set_free_sms_allowance(service_id):
+
+    form = FreeSMSAllowance(free_sms_allowance=current_service['free_sms_fragment_limit'])
+
+    if form.validate_on_submit():
+        service_api_client.update_service(
+            service_id,
+            free_sms_fragment_limit=form.free_sms_allowance.data,
+        )
+        return redirect(url_for('.service_settings', service_id=service_id))
+
+    return render_template(
+        'views/service-settings/set-free-sms-allowance.html',
+        form=form,
+    )
+
+
 @main.route("/services/<service_id>/service-settings/set-branding-and-org", methods=['GET', 'POST'])
 @login_required
 @user_has_permissions(admin_override=True)
diff --git a/app/notify_client/service_api_client.py b/app/notify_client/service_api_client.py
index a35044e6c..49bccdfdd 100644
--- a/app/notify_client/service_api_client.py
+++ b/app/notify_client/service_api_client.py
@@ -104,7 +104,9 @@ class ServiceAPIClient(NotifyAdminAPIClient):
             'organisation',
             'letter_contact_block',
             'dvla_organisation',
-            'permissions'
+            'permissions',
+            'organisation_type',
+            'free_sms_fragment_limit',
         }
         if disallowed_attributes:
             raise TypeError('Not allowed to update service attributes: {}'.format(
diff --git a/app/templates/views/service-settings.html b/app/templates/views/service-settings.html
index 77033ba94..c85a3920b 100644
--- a/app/templates/views/service-settings.html
+++ b/app/templates/views/service-settings.html
@@ -198,7 +198,7 @@
         {% call row() %}
           {{ text_field('Free text message allowance')}}
           {{ text_field('{:,}'.format(current_service.free_sms_fragment_limit)) }}
-          {{ text_field() }}
+          {{ edit_field('Change', url_for('.set_free_sms_allowance', service_id=current_service.id)) }}
         {% endcall %}
         {% call row() %}
           {{ text_field('Email branding' )}}
diff --git a/app/templates/views/service-settings/set-free-sms-allowance.html b/app/templates/views/service-settings/set-free-sms-allowance.html
new file mode 100644
index 000000000..58ff3b36d
--- /dev/null
+++ b/app/templates/views/service-settings/set-free-sms-allowance.html
@@ -0,0 +1,21 @@
+{% extends "withnav_template.html" %}
+{% from "components/textbox.html" import textbox %}
+{% from "components/page-footer.html" import page_footer %}
+
+{% block service_page_title %}
+  Emails
+{% endblock %}
+
+{% block maincolumn_content %}
+
+  <form method="post">
+    <h1 class="heading-large">Free text message allowance</h1>
+    {{ textbox(form.free_sms_allowance) }}
+    {{ page_footer(
+      'Save',
+      back_link=url_for('.service_settings', service_id=current_service.id),
+      back_link_text='Back to settings'
+    ) }}
+  </form>
+
+{% endblock %}
diff --git a/tests/app/main/views/test_service_settings.py b/tests/app/main/views/test_service_settings.py
index d0fa1d07d..e07b27215 100644
--- a/tests/app/main/views/test_service_settings.py
+++ b/tests/app/main/views/test_service_settings.py
@@ -66,7 +66,7 @@ from tests.conftest import (
 
         'Label Value Action',
         'Organisation type Central Change',
-        'Free text message allowance 250,000',
+        'Free text message allowance 250,000 Change',
         'Email branding GOV.UK Change',
         'Letter branding HM Government Change',
 
@@ -1363,12 +1363,17 @@ def test_should_set_branding_and_organisations(
 
 
 @pytest.mark.parametrize('method', ['get', 'post'])
+@pytest.mark.parametrize('endpoint', [
+    'main.set_organisation_type',
+    'main.set_free_sms_allowance',
+])
 def test_organisation_type_pages_are_platform_admin_only(
     client_request,
     method,
+    endpoint,
 ):
     getattr(client_request, method)(
-        'main.set_organisation_type',
+        endpoint,
         service_id=SERVICE_ONE_ID,
         _expected_status=403,
         _test_page_title=False,
@@ -1406,7 +1411,7 @@ def test_should_show_page_to_set_organisation_type(
     'nhs',
     pytest.mark.xfail('private sector'),
 ])
-def test_should_set_organisaton_type(
+def test_should_set_organisation_type(
     logged_in_platform_admin_client,
     mock_update_service,
     organisation_type,
@@ -1430,6 +1435,48 @@ def test_should_set_organisaton_type(
     )
 
 
+def test_should_show_page_to_set_sms_allowance(
+    logged_in_platform_admin_client,
+):
+    response = logged_in_platform_admin_client.get(url_for(
+        'main.set_free_sms_allowance',
+        service_id=SERVICE_ONE_ID
+    ))
+    assert response.status_code == 200
+    page = BeautifulSoup(response.data.decode('utf-8'), 'html.parser')
+
+    assert normalize_spaces(page.select_one('label').text) == 'Numbers of text message fragments per year'
+
+
+@pytest.mark.parametrize('given_allowance, expected_api_argument', [
+    ('1', 1),
+    ('250000', 250000),
+    pytest.mark.xfail(('foo', 'foo')),
+])
+def test_should_set_sms_allowance(
+    logged_in_platform_admin_client,
+    mock_update_service,
+    given_allowance,
+    expected_api_argument,
+):
+    response = logged_in_platform_admin_client.post(
+        url_for(
+            'main.set_free_sms_allowance',
+            service_id=SERVICE_ONE_ID,
+        ),
+        data={
+            'free_sms_allowance': given_allowance,
+        },
+    )
+    assert response.status_code == 302
+    assert response.location == url_for('main.service_settings', service_id=SERVICE_ONE_ID, _external=True)
+
+    mock_update_service.assert_called_once_with(
+        SERVICE_ONE_ID,
+        free_sms_fragment_limit=expected_api_argument,
+    )
+
+
 def test_switch_service_enable_letters(
     logged_in_platform_admin_client,
     service_one,