diff --git a/src/Sequence.php b/src/Sequence.php
index ef8c117e..56a0595c 100644
--- a/src/Sequence.php
+++ b/src/Sequence.php
@@ -221,6 +221,18 @@ public function getGaps(): self
         return $this->gaps();
     }
 
+    /**
+     * Returns the sum of all instances durations as expressed in seconds.
+     */
+    public function getTotalTimestampInterval(): float
+    {
+        $func = function (float $carry, Period $interval): float {
+            return $carry + $interval->getTimestampInterval();
+        };
+
+        return $this->reduce($func, 0);
+    }
+
     /**
      * Tells whether some intervals in the current instance satisfies the predicate.
      */