diff --git a/web/src/settings_components.ts b/web/src/settings_components.ts
index d83f131a5d..e9145e1ff5 100644
--- a/web/src/settings_components.ts
+++ b/web/src/settings_components.ts
@@ -348,22 +348,6 @@ export function set_time_limit_setting(property_name: MessageTimeLimitSetting):
     );
 }
 
-function check_valid_number_input(input_value: string, keep_number_as_float = false): number {
-    // This check is important to make sure that inputs like "24a" are
-    // considered invalid and this function returns NaN for such inputs.
-    // Number.parseInt and Number.parseFloat will convert strings like
-    // "24a" to 24.
-    if (Number.isNaN(Number(input_value))) {
-        return Number.NaN;
-    }
-
-    if (keep_number_as_float) {
-        return Number.parseFloat(Number.parseFloat(input_value).toFixed(1));
-    }
-
-    return Number.parseInt(input_value, 10);
-}
-
 function get_message_retention_setting_value(
     $input_elem: JQuery<HTMLSelectElement>,
     for_api_data = true,
@@ -390,7 +374,7 @@ function get_message_retention_setting_value(
     if (custom_input_val.length === 0) {
         return settings_config.retain_message_forever;
     }
-    return check_valid_number_input(custom_input_val);
+    return util.check_time_input(custom_input_val);
 }
 
 export const select_field_data_schema = z.record(z.object({text: z.string(), order: z.string()}));
@@ -757,7 +741,7 @@ export function get_auth_method_list_data(): Record<string, boolean> {
 }
 
 export function parse_time_limit($elem: JQuery<HTMLInputElement>): number {
-    const time_limit_in_minutes = check_valid_number_input($elem.val()!, true);
+    const time_limit_in_minutes = util.check_time_input($elem.val()!, true);
     return Math.floor(time_limit_in_minutes * 60);
 }
 
@@ -796,7 +780,7 @@ function get_time_limit_setting_value(
     if ($input_elem.attr("id") === "id_realm_waiting_period_threshold") {
         // For realm waiting period threshold setting, the custom input element contains
         // number of days.
-        return check_valid_number_input($custom_input_elem.val()!);
+        return util.check_time_input($custom_input_elem.val()!);
     }
 
     return parse_time_limit($custom_input_elem);
@@ -1336,7 +1320,7 @@ function should_disable_save_button_for_time_limit_settings(
         const $custom_input_elem = $(setting_elem).find<HTMLInputElement>(
             "input.time-limit-custom-input",
         );
-        const custom_input_elem_val = check_valid_number_input($custom_input_elem.val()!);
+        const custom_input_elem_val = util.check_time_input($custom_input_elem.val()!);
 
         const for_realm_default_settings =
             $dropdown_elem.closest(".settings-section.show").attr("id") ===
diff --git a/web/src/util.ts b/web/src/util.ts
index 346f966231..32e3598054 100644
--- a/web/src/util.ts
+++ b/web/src/util.ts
@@ -451,6 +451,22 @@ export function get_custom_time_in_minutes(time_unit: string, time_input: number
     }
 }
 
+export function check_time_input(input_value: string, keep_number_as_float = false): number {
+    // This check is important to make sure that inputs like "24a" are
+    // considered invalid and this function returns NaN for such inputs.
+    // Number.parseInt and Number.parseFloat will convert strings like
+    // "24a" to 24.
+    if (Number.isNaN(Number(input_value))) {
+        return Number.NaN;
+    }
+
+    if (keep_number_as_float) {
+        return Number.parseFloat(Number.parseFloat(input_value).toFixed(1));
+    }
+
+    return Number.parseInt(input_value, 10);
+}
+
 // Helper for shorthand for Typescript to get an item from a list with
 // exactly one item.
 export function the<T>(items: T[] | JQuery<T>): T {
diff --git a/web/tests/util.test.js b/web/tests/util.test.js
index 40e325278e..f93d8777e5 100644
--- a/web/tests/util.test.js
+++ b/web/tests/util.test.js
@@ -404,6 +404,26 @@ run_test("get_custom_time_in_minutes", () => {
     );
 });
 
+run_test("check_and_validate_custom_time_input", () => {
+    const input_is_nan = "24abc";
+    let checked_input = util.check_time_input(input_is_nan);
+    assert.equal(checked_input, Number.NaN);
+
+    const input_is_negative = "-24";
+    checked_input = util.check_time_input(input_is_negative);
+    assert.equal(checked_input, -24);
+
+    const input_is_float = "24.5";
+    checked_input = util.check_time_input(input_is_float);
+    assert.equal(checked_input, 24);
+    checked_input = util.check_time_input(input_is_float, true);
+    assert.equal(checked_input, 24.5);
+
+    const input_is_integer = "10";
+    checked_input = util.check_time_input(input_is_integer);
+    assert.equal(checked_input, 10);
+});
+
 run_test("the", () => {
     const list_with_one_item = ["foo"];
     assert.equal(util.the(list_with_one_item), "foo");