diff --git a/app/Http/Controllers/StudyTrackerController.php b/app/Http/Controllers/StudyTrackerController.php
index 77f165d8..945df03f 100644
--- a/app/Http/Controllers/StudyTrackerController.php
+++ b/app/Http/Controllers/StudyTrackerController.php
@@ -130,7 +130,7 @@ public function logTime(Request $request)
         }
 
         $validated = $request->validate([
-            'seconds' => 'required|integer|min:1|max:86400',
+            'seconds' => 'required|integer|min:1|max:'.DailyStudyLog::MAX_DAILY_SECONDS,
             'date' => 'nullable|date_format:Y-m-d|before_or_equal:today',
         ]);
 
@@ -146,7 +146,7 @@ public function logTime(Request $request)
             ]
         );
 
-        $maxAllowed = max(0, 86400 - (int) $log->total_seconds);
+        $maxAllowed = max(0, DailyStudyLog::MAX_DAILY_SECONDS - (int) $log->total_seconds);
         if ($maxAllowed > 0) {
             $secondsToAdd = min((int) $validated['seconds'], $maxAllowed);
             $log->increment('total_seconds', $secondsToAdd);
diff --git a/app/Models/DailyStudyLog.php b/app/Models/DailyStudyLog.php
index c205b85f..4651f66c 100644
--- a/app/Models/DailyStudyLog.php
+++ b/app/Models/DailyStudyLog.php
@@ -9,6 +9,8 @@
 
 class DailyStudyLog extends Model
 {
+    public const MAX_DAILY_SECONDS = 57600; // 16 hours
+
     protected $fillable = [
         'user_id',
         'study_date',
diff --git a/database/migrations/2026_10_16_124500_drop_excessive_daily_study_logs.php b/database/migrations/2026_10_16_124500_drop_excessive_daily_study_logs.php
new file mode 100644
index 00000000..ed039aee
--- /dev/null
+++ b/database/migrations/2026_10_16_124500_drop_excessive_daily_study_logs.php
@@ -0,0 +1,26 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Support\Facades\DB;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        // 16 hours limit in seconds (16 * 3600 = 57,600)
+        DB::table('daily_study_logs')
+            ->where('total_seconds', '>', 57600)
+            ->delete();
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        // Deleted invalid excessive logs cannot be reconstructed
+    }
+};
diff --git a/resources/js/components/tracker/StopwatchWidget.vue b/resources/js/components/tracker/StopwatchWidget.vue
index 653f77cf..73c54e01 100644
--- a/resources/js/components/tracker/StopwatchWidget.vue
+++ b/resources/js/components/tracker/StopwatchWidget.vue
@@ -166,14 +166,19 @@ function resetTimer() {
     localStorage.removeItem(STORAGE_KEY_ACCUMULATED);
 }
 
+const MAX_DAILY_SECONDS = 57600; // 16 hours max per calendar day
+
 const maxMinutesAllowedForToday = computed(() => {
-    const remainingSeconds = Math.max(0, 86400 - props.todaySeconds);
+    const remainingSeconds = Math.max(
+        0,
+        MAX_DAILY_SECONDS - props.todaySeconds,
+    );
 
     return Math.floor(remainingSeconds / 60);
 });
 
 const isDayMaxReached = computed(() => {
-    return props.todaySeconds >= 86400;
+    return props.todaySeconds >= MAX_DAILY_SECONDS;
 });
 
 function triggerStopwatchSave() {
@@ -187,7 +192,10 @@ function triggerStopwatchSave() {
         return;
     }
 
-    const remainingAllowed = Math.max(0, 86400 - props.todaySeconds);
+    const remainingAllowed = Math.max(
+        0,
+        MAX_DAILY_SECONDS - props.todaySeconds,
+    );
     const secondsToLog = Math.min(elapsedSeconds.value, remainingAllowed);
 
     if (secondsToLog <= 0) {
@@ -212,7 +220,10 @@ function triggerQuickLog(minutes: number) {
     }
 
     const requestedSeconds = minutes * 60;
-    const remainingAllowed = Math.max(0, 86400 - props.todaySeconds);
+    const remainingAllowed = Math.max(
+        0,
+        MAX_DAILY_SECONDS - props.todaySeconds,
+    );
     const secondsToLog = Math.min(requestedSeconds, remainingAllowed);
 
     if (secondsToLog <= 0) {
@@ -639,7 +650,7 @@ const todayFormatted = computed(() => {
                             class="mt-1.5 text-[11px] font-medium text-red-500 dark:text-red-400"
                         >
                             You can log a maximum of
-                            {{ maxMinutesAllowedForToday }} minutes today (24h
+                            {{ maxMinutesAllowedForToday }} minutes today (16h
                             daily limit).
                         </p>
                     </div>
diff --git a/resources/js/pages/Leaderboard/Index.vue b/resources/js/pages/Leaderboard/Index.vue
index ae91836f..157c6a5b 100644
--- a/resources/js/pages/Leaderboard/Index.vue
+++ b/resources/js/pages/Leaderboard/Index.vue
@@ -801,9 +801,18 @@ onBeforeUnmount(() => {
                             class="font-semibold text-slate-800 dark:text-gray-200"
                             >দৈনিক ক্যাপ:</strong
                         >
-                        অবাস্তব সময় যোগ রোধ করতে এক ক্যালেন্ডার দিনে সর্বোচ্চ ২৪
+                        অবাস্তব সময় যোগ রোধ করতে এক ক্যালেন্ডার দিনে সর্বোচ্চ ১৬
                         ঘণ্টার বেশি লগ করা সম্ভব নয়।
                     </li>
+                    <li>
+                        <strong
+                            class="font-semibold text-slate-800 dark:text-gray-200"
+                            >ফেয়ার-প্লে পলিসি:</strong
+                        >
+                        অস্বাভাবিক বা সন্দেহজনক কোনো লগিং কার্যকলাপ পরিলক্ষিত
+                        হলে সংশ্লিষ্ট ব্যবহারকারীকে স্বয়ংক্রিয়ভাবে লিডারবোর্ড
+                        র‍্যাঙ্কিং থেকে বাদ দেওয়া হবে।
+                    </li>
                     <li>
                         <strong
                             class="font-semibold text-slate-800 dark:text-gray-200"
diff --git a/tests/Feature/StudyTrackerTest.php b/tests/Feature/StudyTrackerTest.php
index b6eeddca..a5083026 100644
--- a/tests/Feature/StudyTrackerTest.php
+++ b/tests/Feature/StudyTrackerTest.php
@@ -140,6 +140,37 @@
     ]);
 });
 
+test('logging study time cannot exceed daily max cap of 16 hours', function () {
+    $user = User::factory()->create();
+
+    // Rejects request exceeding max daily limit in single call
+    $this->actingAs($user)
+        ->post('/tracker/log-time', ['seconds' => DailyStudyLog::MAX_DAILY_SECONDS + 1])
+        ->assertSessionHasErrors('seconds');
+
+    // Allows logging up to max daily limit
+    $this->actingAs($user)
+        ->post('/tracker/log-time', ['seconds' => DailyStudyLog::MAX_DAILY_SECONDS])
+        ->assertRedirect();
+
+    $this->assertDatabaseHas('daily_study_logs', [
+        'user_id' => $user->id,
+        'study_date' => Carbon::today()->format('Y-m-d'),
+        'total_seconds' => DailyStudyLog::MAX_DAILY_SECONDS,
+    ]);
+
+    // Subsequent logs within the same day are capped at max
+    $this->actingAs($user)
+        ->post('/tracker/log-time', ['seconds' => 600])
+        ->assertRedirect();
+
+    $log = DailyStudyLog::where('user_id', $user->id)
+        ->where('study_date', Carbon::today()->format('Y-m-d'))
+        ->first();
+
+    expect($log->total_seconds)->toBe(DailyStudyLog::MAX_DAILY_SECONDS);
+});
+
 test('tracker only includes trackable subjects and trackable nodes flatly', function () {
     $trackableSubject = Subject::create([
         'name' => 'Trackable Subject',