diff --git a/app/Http/Controllers/PayrollRunController.php b/app/Http/Controllers/PayrollRunController.php
index 6c922a55b..c950bc03a 100644
--- a/app/Http/Controllers/PayrollRunController.php
+++ b/app/Http/Controllers/PayrollRunController.php
@@ -97,7 +97,6 @@ class PayrollRunController extends Controller
         if (Auth::user()->can('create-payroll-runs')) {
             $validated = $request->validate([
                 'title' => 'required|string|max:255',
-                'payroll_frequency' => 'required|in:weekly,biweekly,semi-monthly,monthly',
                 'pay_period_start' => 'required|date',
                 'pay_period_end' => 'required|date|after:pay_period_start',
                 'pay_date' => 'required|date|after_or_equal:pay_period_end',
@@ -106,6 +105,16 @@ class PayrollRunController extends Controller
 
             $validated['created_by'] = creatorId();
             $validated['status'] = 'draft';
+            
+            // Dynamically calculate frequency
+            $daysDiff = \Carbon\Carbon::parse($validated['pay_period_start'])->diffInDays(\Carbon\Carbon::parse($validated['pay_period_end'])) + 1;
+            if ($daysDiff >= 28) {
+                $validated['payroll_frequency'] = 'monthly';
+            } elseif ($daysDiff <= 7) {
+                $validated['payroll_frequency'] = 'weekly';
+            } else {
+                $validated['payroll_frequency'] = 'semi-monthly';
+            }
 
             // Check if payroll run already exists for this period
             $exists = PayrollRun::where('pay_period_start', $validated['pay_period_start'])
@@ -136,12 +145,21 @@ class PayrollRunController extends Controller
                 try {
                     $validated = $request->validate([
                         'title' => 'required|string|max:255',
-                        'payroll_frequency' => 'required|in:weekly,biweekly,semi-monthly,monthly',
                         'pay_period_start' => 'required|date',
                         'pay_period_end' => 'required|date|after:pay_period_start',
                         'pay_date' => 'required|date|after_or_equal:pay_period_end',
                         'notes' => 'nullable|string',
                     ]);
+                    
+                    // Dynamically calculate frequency
+                    $daysDiff = \Carbon\Carbon::parse($validated['pay_period_start'])->diffInDays(\Carbon\Carbon::parse($validated['pay_period_end'])) + 1;
+                    if ($daysDiff >= 28) {
+                        $validated['payroll_frequency'] = 'monthly';
+                    } elseif ($daysDiff <= 7) {
+                        $validated['payroll_frequency'] = 'weekly';
+                    } else {
+                        $validated['payroll_frequency'] = 'semi-monthly';
+                    }
 
                     // Only allow updates if status is draft
                     if ($payrollRun->status !== 'draft') {
@@ -331,12 +349,11 @@ class PayrollRunController extends Controller
 
                 $callback = function () use ($payrollRuns) {
                     $file = fopen('php://output', 'w');
-                    fputcsv($file, ['Title', 'Payroll Frequency', 'Pay Period Start', 'Pay Period End', 'Pay Date', 'Status', 'Notes']);
+                    fputcsv($file, ['Title', 'Pay Period Start', 'Pay Period End', 'Pay Date', 'Status', 'Notes']);
 
                     foreach ($payrollRuns as $run) {
                         fputcsv($file, [
                             $run->title,
-                            $run->payroll_frequency,
                             \Carbon\Carbon::parse($run->pay_period_start)->format('Y-m-d'),
                             \Carbon\Carbon::parse($run->pay_period_end)->format('Y-m-d'),
                             \Carbon\Carbon::parse($run->pay_date)->format('Y-m-d'),
@@ -457,9 +474,19 @@ class PayrollRunController extends Controller
                             continue;
                         }
 
+                        // Dynamically calculate frequency
+                        $daysDiff = \Carbon\Carbon::parse($row['pay_period_start'])->diffInDays(\Carbon\Carbon::parse($row['pay_period_end'])) + 1;
+                        if ($daysDiff >= 28) {
+                            $calcFreq = 'monthly';
+                        } elseif ($daysDiff <= 7) {
+                            $calcFreq = 'weekly';
+                        } else {
+                            $calcFreq = 'semi-monthly';
+                        }
+
                         PayrollRun::create([
                             'title' => $row['title'],
-                            'payroll_frequency' => $row['payroll_frequency'] ?? 'monthly',
+                            'payroll_frequency' => $calcFreq,
                             'pay_period_start' => $row['pay_period_start'],
                             'pay_period_end' => $row['pay_period_end'],
                             'pay_date' => $row['pay_date'],