diff --git a/UPGRADE.md b/UPGRADE.md
new file mode 100644
index 0000000..cc147fd
--- /dev/null
+++ b/UPGRADE.md
@@ -0,0 +1,42 @@
+# Upgrade Guide
+
+## 0.5.0
+
+Two new `integer` columns were added to the `processed_messages` table:
+`wait_time` and `handle_time`. You will need to create a migration to
+add these columns to your database. They are not nullable so your
+migration will need to account for existing data. You can either
+truncate (purge) the `processed_messages` table have your migration
+calculate these values based on the existing data.
+
+Here's a calculation example for MySQL:
+
+```php
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+final class VersionXXX extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Add processed_messages.wait_time and handle_time columns';
+    }
+
+    public function up(Schema $schema): void
+    {
+        // Add the columns as nullable
+        $this->addSql('ALTER TABLE processed_messages ADD wait_time INT DEFAULT NULL, ADD handle_time INT DEFAULT NULL');
+
+        // set the times from existing data
+        $this->addSql('UPDATE processed_messages SET wait_time = TIMESTAMPDIFF(SECOND, dispatched_at, received_at), handle_time = TIMESTAMPDIFF(SECOND, received_at, finished_at)');
+
+        // Make the columns not nullable
+        $this->addSql('ALTER TABLE processed_messages CHANGE wait_time wait_time INT NOT NULL, CHANGE handle_time handle_time INT NOT NULL');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE processed_messages DROP wait_time, DROP handle_time');
+    }
+}
+```
diff --git a/config/doctrine/mapping/ProcessedMessage.orm.xml b/config/doctrine/mapping/ProcessedMessage.orm.xml
index f2408fe..a03e201 100644
--- a/config/doctrine/mapping/ProcessedMessage.orm.xml
+++ b/config/doctrine/mapping/ProcessedMessage.orm.xml
@@ -11,6 +11,8 @@
         <field name="dispatchedAt" column="dispatched_at" type="datetime_immutable" />
         <field name="receivedAt" column="received_at" type="datetime_immutable" />
         <field name="finishedAt" column="finished_at" type="datetime_immutable" />
+        <field name="waitTime" column="wait_time" type="integer" />
+        <field name="handleTime" column="handle_time" type="integer" />
         <field name="memoryUsage" column="memory_usage" type="integer" />
         <field name="transport" column="transport" />
         <field name="tags" column="tags" nullable="true" />
diff --git a/src/History/Model/ProcessedMessage.php b/src/History/Model/ProcessedMessage.php
index 268cfd7..88198ec 100644
--- a/src/History/Model/ProcessedMessage.php
+++ b/src/History/Model/ProcessedMessage.php
@@ -37,6 +37,8 @@ abstract class ProcessedMessage
     private int $memoryUsage;
     private string $transport;
     private ?string $tags;
+    private int $waitTime;
+    private int $handleTime;
 
     /** @var class-string<\Throwable> */
     private ?string $failureType = null;
@@ -61,6 +63,8 @@ public function __construct(Envelope $envelope, Results $results, ?\Throwable $e
         $this->transport = $monitorStamp->transport();
         $this->tags = $tags->count() ? (string) $tags : null;
         $this->results = $results;
+        $this->waitTime = \max(0, $this->receivedAt->getTimestamp() - $this->dispatchedAt->getTimestamp());
+        $this->handleTime = \max(0, $this->finishedAt->getTimestamp() - $this->receivedAt->getTimestamp());
 
         if ($retryStamp = $envelope->last(RedeliveryStamp::class)) {
             $this->attempt += $retryStamp->getRetryCount();
@@ -143,17 +147,17 @@ final public function isFailure(): bool
 
     final public function timeInQueue(): int
     {
-        return \max(0, $this->receivedAt->getTimestamp() - $this->dispatchedAt->getTimestamp());
+        return $this->waitTime;
     }
 
     final public function timeToHandle(): int
     {
-        return \max(0, $this->finishedAt->getTimestamp() - $this->receivedAt->getTimestamp());
+        return $this->handleTime;
     }
 
     final public function timeToProcess(): int
     {
-        return \max(0, $this->finishedAt->getTimestamp() - $this->dispatchedAt->getTimestamp());
+        return $this->waitTime + $this->handleTime;
     }
 
     final public function memoryUsage(): Bytes
diff --git a/src/History/Storage/ORMStorage.php b/src/History/Storage/ORMStorage.php
index bbf1863..f67c71f 100644
--- a/src/History/Storage/ORMStorage.php
+++ b/src/History/Storage/ORMStorage.php
@@ -92,7 +92,7 @@ public function averageWaitTime(Specification $specification): ?float
     {
         $qb = $this
             ->queryBuilderFor($specification, false)
-            ->select('AVG(m.receivedAt - m.dispatchedAt)')
+            ->select('AVG(m.waitTime)')
         ;
 
         return (new EntityResult($qb))->asFloat()->first();
@@ -102,7 +102,7 @@ public function averageHandlingTime(Specification $specification): ?float
     {
         $qb = $this
             ->queryBuilderFor($specification, false)
-            ->select('AVG(m.finishedAt - m.receivedAt)')
+            ->select('AVG(m.handleTime)')
         ;
 
         return (new EntityResult($qb))->asFloat()->first();
diff --git a/tests/Fixture/Factory/ProcessedMessageFactory.php b/tests/Fixture/Factory/ProcessedMessageFactory.php
index 09eca70..20b06b7 100644
--- a/tests/Fixture/Factory/ProcessedMessageFactory.php
+++ b/tests/Fixture/Factory/ProcessedMessageFactory.php
@@ -29,6 +29,17 @@ protected function initialize(): static
     {
         return parent::initialize()
             ->instantiateWith(Instantiator::withoutConstructor()->alwaysForce())
+            ->beforeInstantiate(function(array $attributes) {
+                if (!isset($attributes['waitTime'])) {
+                    $attributes['waitTime'] = \max(0, $attributes['receivedAt']->getTimestamp() - $attributes['dispatchedAt']->getTimestamp());
+                }
+
+                if (!isset($attributes['processingTime'])) {
+                    $attributes['handleTime'] = \max(0, $attributes['finishedAt']->getTimestamp() - $attributes['receivedAt']->getTimestamp());
+                }
+
+                return $attributes;
+            })
         ;
     }