diff --git a/CHANGELOG.md b/CHANGELOG.md
index ea0d51d1..feac5dfe 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ All notable changes to this project will be documented in this file.
 - Update the read-only dashboard's CSS for better mobile support (#442)
 - Reduce the number of SQL queries used in the "Get Checks" API call
 - Add support for script's exit status in ping URLs (#429)
+- Improve phone number sanitization: remove spaces and hyphens
 
 ## v1.17.0 - 2020-10-14
 
diff --git a/hc/front/forms.py b/hc/front/forms.py
index b5f33626..14b82b6a 100644
--- a/hc/front/forms.py
+++ b/hc/front/forms.py
@@ -204,6 +204,7 @@ class AddSmsForm(forms.Form):
         v = self.cleaned_data["value"]
 
         stripped = v.encode("ascii", "ignore").decode("ascii")
+        stripped = stripped.replace(" ", "").replace("-", "")
         if not re.match(r"^\+\d{5,15}$", stripped):
             raise forms.ValidationError("Invalid phone number format.")
 
diff --git a/hc/front/tests/test_add_sms.py b/hc/front/tests/test_add_sms.py
index 73a6fe10..ca062820 100644
--- a/hc/front/tests/test_add_sms.py
+++ b/hc/front/tests/test_add_sms.py
@@ -75,3 +75,23 @@ class AddSmsTestCase(BaseTestCase):
 
         c = Channel.objects.get()
         self.assertEqual(c.phone_number, "+1234567890")
+
+    def test_it_strips_hyphens(self):
+        form = {"label": "My Phone", "value": "+123-4567890"}
+
+        self.client.login(username="alice@example.org", password="password")
+        r = self.client.post(self.url, form)
+        self.assertRedirects(r, self.channels_url)
+
+        c = Channel.objects.get()
+        self.assertEqual(c.phone_number, "+1234567890")
+
+    def test_it_strips_spaces(self):
+        form = {"label": "My Phone", "value": "+123 45 678 90"}
+
+        self.client.login(username="alice@example.org", password="password")
+        r = self.client.post(self.url, form)
+        self.assertRedirects(r, self.channels_url)
+
+        c = Channel.objects.get()
+        self.assertEqual(c.phone_number, "+1234567890")