diff --git a/src/application/controllers/Appointments.php b/src/application/controllers/Appointments.php
index d6de49b9..007e39d1 100755
--- a/src/application/controllers/Appointments.php
+++ b/src/application/controllers/Appointments.php
@@ -289,6 +289,7 @@ class Appointments extends CI_Controller {
         $this->load->model('providers_model');
         $this->load->model('appointments_model');
         $this->load->model('settings_model');
+        $this->load->model('services_model');
 
         try {
 			// Do not continue if there was no provider selected (more likely there is no provider in the system).
@@ -313,11 +314,14 @@ class Appointments extends CI_Controller {
 				}
 			}
 
+            $availabilities_type = $this->services_model->get_value('availabilities_type', $_POST['service_id']);
+
 			$empty_periods = $this->_get_provider_available_time_periods($_POST['provider_id'],
 					$_POST['selected_date'], $exclude_appointments);
 
             $available_hours = $this->_calculate_available_hours($empty_periods, $_POST['selected_date'],
-					$_POST['service_duration'], filter_var($_POST['manage_mode'], FILTER_VALIDATE_BOOLEAN));
+					$_POST['service_duration'], filter_var($_POST['manage_mode'], FILTER_VALIDATE_BOOLEAN), 
+                    $availabilities_type);
 
             echo json_encode($available_hours);
 
@@ -501,7 +505,8 @@ class Appointments extends CI_Controller {
 
 			// Get the available time periods for every day of this month.
 			$this->load->model('services_model');
-			$service_duration = (int)$this->services_model->get_value('duration', $service_id);
+            $service_duration = (int)$this->services_model->get_value('duration', $service_id);
+			$availabilities_type = (int)$this->services_model->get_value('availabilities_type', $service_id);
 
 			for ($i=1; $i<=$number_of_days; $i++) {
 				$current_date = new DateTime($selected_date->format('Y-m') . '-' . $i);
@@ -515,7 +520,7 @@ class Appointments extends CI_Controller {
 						$current_date->format('Y-m-d'));
 
 	            $available_hours = $this->_calculate_available_hours($empty_periods, $current_date->format('Y-m-d'),
-						$service_duration);
+						$service_duration, false, $availabilities_type);
 
 				if (empty($available_hours)) {
 					$unavailable_dates[] = $current_date->format('Y-m-d');
@@ -754,7 +759,8 @@ class Appointments extends CI_Controller {
 			foreach($provider['services'] as $provider_service_id) {
 				if ($provider_service_id == $service_id) { // Check if the provider is available for the requested date.
 					$empty_periods = $this->_get_provider_available_time_periods($provider['id'], $selected_date);
-					$available_hours = $this->_calculate_available_hours($empty_periods, $selected_date, $service['duration']);
+					$available_hours = $this->_calculate_available_hours($empty_periods, $selected_date, 
+                            $service['duration'], false, $service['availabilities_type']);
 					if (count($available_hours) > $max_hours_count) {
 						$provider_id = $provider['id'];
 						$max_hours_count = count($available_hours);
@@ -778,11 +784,12 @@ class Appointments extends CI_Controller {
 	 * @param string $selected_date The selected date to be search (format )
 	 * @param numeric $service_duration The service duration is required for the hour calculation.
 	 * @param bool $manage_mode (optional) Whether we are currently on manage mode (editing an existing appointment).
+     * @param string $availlabilities_type Optional ('flexible'), the service availabilities type.
 	 *
 	 * @return array Returns an array with the available hours for the appointment.
 	 */
 	protected function _calculate_available_hours(array $empty_periods, $selected_date, $service_duration,
-			$manage_mode = FALSE) {
+			$manage_mode = FALSE, $availabilities_type = 'flexible') {
 		$this->load->model('settings_model');
 
 		$available_hours = array();
@@ -790,29 +797,14 @@ class Appointments extends CI_Controller {
 		foreach ($empty_periods as $period) {
 			$start_hour = new DateTime($selected_date . ' ' . $period['start']);
 			$end_hour = new DateTime($selected_date . ' ' . $period['end']);
-
-			$minutes = $start_hour->format('i');
-
-			if ($minutes % 15 != 0) {
-				// Change the start hour of the current space in order to be
-				// on of the following: 00, 15, 30, 45.
-				if ($minutes < 15) {
-					$start_hour->setTime($start_hour->format('H'), 15);
-				} else if ($minutes < 30) {
-					$start_hour->setTime($start_hour->format('H'), 30);
-				} else if ($minutes < 45) {
-					$start_hour->setTime($start_hour->format('H'), 45);
-				} else {
-					$start_hour->setTime($start_hour->format('H') + 1, 00);
-				}
-			}
+            $interval = $availabilities_type === AVAILABILITIES_TYPE_FIXED ? (int)$service_duration : 15; 
 
 			$current_hour = $start_hour;
 			$diff = $current_hour->diff($end_hour);
 
 			while (($diff->h * 60 + $diff->i) >= intval($service_duration)) {
 				$available_hours[] = $current_hour->format('H:i');
-				$current_hour->add(new DateInterval("PT15M"));
+				$current_hour->add(new DateInterval('PT' . $interval . 'M'));
 				$diff = $current_hour->diff($end_hour);
 			}
 		}
diff --git a/src/application/controllers/api/v1/Availabilities.php b/src/application/controllers/api/v1/Availabilities.php
index 3a01c349..8b3e983b 100644
--- a/src/application/controllers/api/v1/Availabilities.php
+++ b/src/application/controllers/api/v1/Availabilities.php
@@ -59,7 +59,7 @@ class Availabilities extends API_V1_Controller {
                     $date->format('Y-m-d'), []);
             
             $availableHours = $this->_calculateAvailableHours($emptyPeriods, 
-                    $date->format('Y-m-d'), $service['duration'], false);
+                    $date->format('Y-m-d'), $service['duration'], false, $service['availabilities_type']);
 
             $this->output
                 ->set_content_type('application/json') 
@@ -231,11 +231,12 @@ class Availabilities extends API_V1_Controller {
      * @param string $selected_date The selected date to be search (format )
      * @param numeric $service_duration The service duration is required for the hour calculation.
      * @param bool $manage_mode (optional) Whether we are currently on manage mode (editing an existing appointment).
+     * @param string $availlabilities_type Optional ('flexible'), the service availabilities type.
      *
      * @return array Returns an array with the available hours for the appointment.
      */
     protected function _calculateAvailableHours(array $empty_periods, $selected_date, $service_duration,
-            $manage_mode = FALSE) {
+            $manage_mode = FALSE, $availabilities_type = 'flexible') {
         $this->load->model('settings_model');
 
         $available_hours = array();
@@ -243,29 +244,14 @@ class Availabilities extends API_V1_Controller {
         foreach ($empty_periods as $period) {
             $start_hour = new DateTime($selected_date . ' ' . $period['start']);
             $end_hour = new DateTime($selected_date . ' ' . $period['end']);
-
-            $minutes = $start_hour->format('i');
-
-            if ($minutes % 15 != 0) {
-                // Change the start hour of the current space in order to be
-                // on of the following: 00, 15, 30, 45.
-                if ($minutes < 15) {
-                    $start_hour->setTime($start_hour->format('H'), 15);
-                } else if ($minutes < 30) {
-                    $start_hour->setTime($start_hour->format('H'), 30);
-                } else if ($minutes < 45) {
-                    $start_hour->setTime($start_hour->format('H'), 45);
-                } else {
-                    $start_hour->setTime($start_hour->format('H') + 1, 00);
-                }
-            }
+            $interval = $availabilities_type === AVAILABILITIES_TYPE_FIXED ? (int)$service_duration : 15; 
 
             $current_hour = $start_hour;
             $diff = $current_hour->diff($end_hour);
 
             while (($diff->h * 60 + $diff->i) >= intval($service_duration)) {
                 $available_hours[] = $current_hour->format('H:i');
-                $current_hour->add(new DateInterval("PT15M"));
+                $current_hour->add(new DateInterval('PT' . $interval . 'M'));
                 $diff = $current_hour->diff($end_hour);
             }
         }