diff --git a/custom/apps/mining-checker/src/Domain/AnalyticsService.php b/custom/apps/mining-checker/src/Domain/AnalyticsService.php
index f349c7b3..95589c54 100644
--- a/custom/apps/mining-checker/src/Domain/AnalyticsService.php
+++ b/custom/apps/mining-checker/src/Domain/AnalyticsService.php
@@ -2208,7 +2208,8 @@ final class AnalyticsService
         $monthIndex = (((int) $start->format('Y')) * 12) + ((int) $start->format('n')) - 1 + $runtimeMonths;
         $year = intdiv($monthIndex, 12);
         $month = ($monthIndex % 12) + 1;
-        $day = min((int) $start->format('j'), cal_days_in_month(CAL_GREGORIAN, $month, $year));
+        $daysInTargetMonth = (int) $start->setDate($year, $month, 1)->format('t');
+        $day = min((int) $start->format('j'), $daysInTargetMonth);
 
         return $start->setDate($year, $month, $day)->getTimestamp();
     }
diff --git a/custom/apps/mining-checker/src/Infrastructure/MiningRepository.php b/custom/apps/mining-checker/src/Infrastructure/MiningRepository.php
index 007434b5..3eb1ea7b 100644
--- a/custom/apps/mining-checker/src/Infrastructure/MiningRepository.php
+++ b/custom/apps/mining-checker/src/Infrastructure/MiningRepository.php
@@ -1727,7 +1727,8 @@ final class MiningRepository
             $monthIndex = (((int) $start->format('Y')) * 12) + ((int) $start->format('n')) - 1 + $months;
             $year = intdiv($monthIndex, 12);
             $month = ($monthIndex % 12) + 1;
-            $day = min((int) $start->format('j'), cal_days_in_month(CAL_GREGORIAN, $month, $year));
+            $daysInTargetMonth = (int) $start->setDate($year, $month, 1)->format('t');
+            $day = min((int) $start->format('j'), $daysInTargetMonth);
             $end = $start->setDate($year, $month, $day);
             $runtimeDays = ($end->getTimestamp() - $start->getTimestamp()) / 86400;
         } catch (\Throwable) {