diff --git a/app/Features/CustomMonthStartDay.php b/app/Features/CustomMonthStartDay.php
new file mode 100644
index 00000000..9c1ecd46
--- /dev/null
+++ b/app/Features/CustomMonthStartDay.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace App\Features;
+
+use App\Models\User;
+
+/**
+ * @api
+ */
+class CustomMonthStartDay
+{
+    /**
+     * Resolve the feature's initial value.
+     */
+    public function resolve(?User $user): bool
+    {
+        return false;
+    }
+}
diff --git a/app/Http/Middleware/HandleInertiaRequests.php b/app/Http/Middleware/HandleInertiaRequests.php
index f26c94e8..3bf45645 100644
--- a/app/Http/Middleware/HandleInertiaRequests.php
+++ b/app/Http/Middleware/HandleInertiaRequests.php
@@ -4,6 +4,7 @@ namespace App\Http\Middleware;
 
 use App\Enums\BankingConnectionStatus;
 use App\Features\CalculateBalancesOnImport;
+use App\Features\CustomMonthStartDay;
 use App\Features\TransactionAnalysis;
 use App\Models\BankingConnection;
 use App\Services\CurrencyOptions;
@@ -168,18 +169,21 @@ class HandleInertiaRequests extends Middleware
             return [
                 'cashflow' => true,
                 'calculateBalancesOnImport' => false,
+                'customMonthStartDay' => false,
                 'transactionAnalysis' => false,
             ];
         }
 
         $features = Feature::for($user)->values([
             CalculateBalancesOnImport::class,
+            CustomMonthStartDay::class,
             TransactionAnalysis::class,
         ]);
 
         return [
             'cashflow' => true,
             'calculateBalancesOnImport' => $features[CalculateBalancesOnImport::class] !== false,
+            'customMonthStartDay' => $features[CustomMonthStartDay::class] !== false,
             'transactionAnalysis' => $features[TransactionAnalysis::class] !== false,
         ];
     }
diff --git a/app/Http/Requests/Settings/ProfileUpdateRequest.php b/app/Http/Requests/Settings/ProfileUpdateRequest.php
index 4d30e587..520ecfbf 100644
--- a/app/Http/Requests/Settings/ProfileUpdateRequest.php
+++ b/app/Http/Requests/Settings/ProfileUpdateRequest.php
@@ -2,12 +2,14 @@
 
 namespace App\Http\Requests\Settings;
 
+use App\Features\CustomMonthStartDay;
 use App\Models\User;
 use App\Services\CurrencyOptions;
 use App\Services\UserMonthPeriodService;
 use Illuminate\Contracts\Validation\ValidationRule;
 use Illuminate\Foundation\Http\FormRequest;
 use Illuminate\Validation\Rule;
+use Laravel\Pennant\Feature;
 
 class ProfileUpdateRequest extends FormRequest
 {
@@ -20,7 +22,7 @@ class ProfileUpdateRequest extends FormRequest
     {
         $currencyOptions = app(CurrencyOptions::class);
 
-        return [
+        $rules = [
             'name' => ['required', 'string', 'max:255'],
 
             'email' => [
@@ -33,7 +35,12 @@ class ProfileUpdateRequest extends FormRequest
             ],
             'currency_code' => ['required', 'string', 'max:3', Rule::in($currencyOptions->primaryCodes())],
             'locale' => ['nullable', 'string', Rule::in(['en', 'es'])],
-            'month_start_day' => ['required', 'integer', Rule::in(UserMonthPeriodService::ALLOWED_START_DAYS)],
         ];
+
+        if (Feature::for($this->user())->active(CustomMonthStartDay::class)) {
+            $rules['month_start_day'] = ['required', 'integer', Rule::in(UserMonthPeriodService::ALLOWED_START_DAYS)];
+        }
+
+        return $rules;
     }
 }
diff --git a/resources/js/pages/settings/account.tsx b/resources/js/pages/settings/account.tsx
index 01cb7c96..0e3ecb44 100644
--- a/resources/js/pages/settings/account.tsx
+++ b/resources/js/pages/settings/account.tsx
@@ -52,7 +52,7 @@ export default function Account({
     twoFactorEnabled?: boolean;
     notifyOnBankTransactionsSynced?: boolean;
 }) {
-    const { auth, currencies } = usePage<SharedData>().props;
+    const { auth, currencies, features } = usePage<SharedData>().props;
     const passwordInput = useRef<HTMLInputElement>(null);
     const currentPasswordInput = useRef<HTMLInputElement>(null);
     const [notifyBankTransactions, setNotifyBankTransactions] = useState(
@@ -218,53 +218,55 @@ export default function Account({
                                     />
                                 </div>
 
-                                <div className="grid gap-2">
-                                    <Label htmlFor="month_start_day">
-                                        {__('Start of month')}
-                                    </Label>
+                                {features.customMonthStartDay && (
+                                    <div className="grid gap-2">
+                                        <Label htmlFor="month_start_day">
+                                            {__('Start of month')}
+                                        </Label>
 
-                                    <Select
-                                        name="month_start_day"
-                                        defaultValue={String(
-                                            auth.user.month_start_day ?? 1,
-                                        )}
-                                        required
-                                    >
-                                        <SelectTrigger className="mt-1 w-full">
-                                            <SelectValue
-                                                placeholder={__(
-                                                    'Select start of month',
-                                                )}
-                                            />
-                                        </SelectTrigger>
-                                        <SelectContent>
-                                            <SelectItem value="1">
-                                                {__('Calendar month (1st)')}
-                                            </SelectItem>
-                                            {[25, 26, 27, 28].map((day) => (
-                                                <SelectItem
-                                                    key={day}
-                                                    value={String(day)}
-                                                >
-                                                    {__('Day :day', {
-                                                        day: String(day),
-                                                    })}
+                                        <Select
+                                            name="month_start_day"
+                                            defaultValue={String(
+                                                auth.user.month_start_day ?? 1,
+                                            )}
+                                            required
+                                        >
+                                            <SelectTrigger className="mt-1 w-full">
+                                                <SelectValue
+                                                    placeholder={__(
+                                                        'Select start of month',
+                                                    )}
+                                                />
+                                            </SelectTrigger>
+                                            <SelectContent>
+                                                <SelectItem value="1">
+                                                    {__('Calendar month (1st)')}
                                                 </SelectItem>
-                                            ))}
-                                        </SelectContent>
-                                    </Select>
+                                                {[25, 26, 27, 28].map((day) => (
+                                                    <SelectItem
+                                                        key={day}
+                                                        value={String(day)}
+                                                    >
+                                                        {__('Day :day', {
+                                                            day: String(day),
+                                                        })}
+                                                    </SelectItem>
+                                                ))}
+                                            </SelectContent>
+                                        </Select>
 
-                                    <p className="text-sm text-muted-foreground">
-                                        {__(
-                                            'Cashflow periods and analysis will start on this day.',
-                                        )}
-                                    </p>
+                                        <p className="text-sm text-muted-foreground">
+                                            {__(
+                                                'Cashflow periods and analysis will start on this day.',
+                                            )}
+                                        </p>
 
-                                    <InputError
-                                        className="mt-2"
-                                        message={errors.month_start_day}
-                                    />
-                                </div>
+                                        <InputError
+                                            className="mt-2"
+                                            message={errors.month_start_day}
+                                        />
+                                    </div>
+                                )}
 
                                 {mustVerifyEmail &&
                                     auth.user.email_verified_at === null && (
diff --git a/resources/js/types/index.d.ts b/resources/js/types/index.d.ts
index 28777701..796761fb 100644
--- a/resources/js/types/index.d.ts
+++ b/resources/js/types/index.d.ts
@@ -42,6 +42,7 @@ export interface NavDivider {
 export interface Features {
     cashflow: boolean;
     calculateBalancesOnImport: boolean;
+    customMonthStartDay: boolean;
     transactionAnalysis: boolean;
 }
 
diff --git a/tests/Feature/Settings/ProfileUpdateTest.php b/tests/Feature/Settings/ProfileUpdateTest.php
index c0614a79..3d77e908 100644
--- a/tests/Feature/Settings/ProfileUpdateTest.php
+++ b/tests/Feature/Settings/ProfileUpdateTest.php
@@ -1,6 +1,8 @@
 <?php
 
+use App\Features\CustomMonthStartDay;
 use App\Models\User;
+use Laravel\Pennant\Feature;
 
 test('profile page is displayed', function () {
     $user = User::factory()->create();
@@ -14,6 +16,7 @@ test('profile page is displayed', function () {
 
 test('profile information can be updated', function () {
     $user = User::factory()->create();
+    Feature::for($user)->activate(CustomMonthStartDay::class);
 
     $response = $this
         ->actingAs($user)
@@ -130,6 +133,7 @@ test('profile rejects bitcoin as primary currency', function () {
 
 test('profile rejects unsupported month start day', function () {
     $user = User::factory()->create();
+    Feature::for($user)->activate(CustomMonthStartDay::class);
 
     $response = $this
         ->actingAs($user)
@@ -143,6 +147,25 @@ test('profile rejects unsupported month start day', function () {
     $response->assertSessionHasErrors(['month_start_day']);
 });
 
+test('profile ignores month start day when feature is disabled', function () {
+    $user = User::factory()->create(['month_start_day' => 1]);
+
+    $response = $this
+        ->actingAs($user)
+        ->patch(route('profile.update'), [
+            'name' => 'Test User',
+            'email' => 'test@example.com',
+            'currency_code' => 'USD',
+            'month_start_day' => 25,
+        ]);
+
+    $response
+        ->assertSessionHasNoErrors()
+        ->assertRedirect(route('account.edit'));
+
+    expect($user->refresh()->month_start_day)->toBe(1);
+});
+
 test('email verification status is unchanged when the email address is unchanged', function () {
     $user = User::factory()->create();