diff --git a/client/src/Pages/CreateMonitor/index.tsx b/client/src/Pages/CreateMonitor/index.tsx
index 2bda92e62..465b9d15d 100644
--- a/client/src/Pages/CreateMonitor/index.tsx
+++ b/client/src/Pages/CreateMonitor/index.tsx
@@ -1117,6 +1117,15 @@ const CreateMonitorPage = () => {
 													"pages.createMonitor.form.advanced.option.customUpCodes.label"
 												)}
 											/>
+											<Typography
+												component="span"
+												color={theme.palette.text.secondary}
+												sx={{ opacity: 0.8 }}
+											>
+												{t(
+													"pages.createMonitor.form.advanced.option.customUpCodes.description"
+												)}
+											</Typography>
 											{selectedOptions.length > 0 && (
 												<Stack
 													flex={1}
diff --git a/client/src/Utils/statusCode.ts b/client/src/Utils/statusCode.ts
index 7b5448d2e..362a7f3b7 100644
--- a/client/src/Utils/statusCode.ts
+++ b/client/src/Utils/statusCode.ts
@@ -80,6 +80,9 @@ export interface HttpStatusCodeOption {
 	name: string;
 }
 
+/**
+ * Must stay in sync with HttpStatusCodes in server/src/domain/monitors/monitor.types.ts
+ */
 export const ALL_HTTP_STATUS_CODES: HttpStatusCodeOption[] = [
 	{ id: 100, name: "100 - Continue" },
 	{ id: 101, name: "101 - Switching Protocols" },
diff --git a/client/src/locales/en.json b/client/src/locales/en.json
index 5d68cc1c3..6e65aea62 100644
--- a/client/src/locales/en.json
+++ b/client/src/locales/en.json
@@ -508,6 +508,7 @@
 						},
 						"customUpCodes": {
 							"label": "Accepted status codes",
+							"description": "Add any non-2xx codes that should also be considered successful.",
 							"removeAriaLabel": "Remove status code"
 						}
 					},