diff --git a/src/DefaultTimeoutChecker.php b/src/DefaultTimeoutChecker.php
new file mode 100644
index 00000000..cb561526
--- /dev/null
+++ b/src/DefaultTimeoutChecker.php
@@ -0,0 +1,35 @@
+<?php
+
+/**
+ * Box packing (3D bin packing, knapsack problem).
+ *
+ * @author Doug Wright
+ */
+declare(strict_types=1);
+
+namespace DVDoug\BoxPacker;
+
+use DVDoug\BoxPacker\Exception\TimeoutException;
+
+class DefaultTimeoutChecker implements TimeoutChecker
+{
+    private float $startTime;
+
+    public function __construct(readonly private float $timeout)
+    {
+    }
+
+    public function start(?float $startTime = null): void
+    {
+        $this->startTime = $startTime ?? \microtime(true);
+    }
+
+    public function throwOnTimeout(?float $currentTime = null, string $message = 'Exceeded the timeout'): void
+    {
+        $spentTime = ($currentTime ?? \microtime(true)) - $this->startTime;
+        $isTimeout = $spentTime >= $this->timeout;
+        if ($isTimeout) {
+            throw new TimeoutException($message, $spentTime, $this->timeout);
+        }
+    }
+}
diff --git a/src/Exception/TimeoutException.php b/src/Exception/TimeoutException.php
new file mode 100644
index 00000000..aff7a243
--- /dev/null
+++ b/src/Exception/TimeoutException.php
@@ -0,0 +1,33 @@
+<?php
+
+/**
+ * Box packing (3D bin packing, knapsack problem).
+ *
+ * @author Doug Wright
+ */
+declare(strict_types=1);
+
+namespace DVDoug\BoxPacker\Exception;
+
+use RuntimeException;
+
+/**
+ * Exception used when the timeout occurred
+ */
+class TimeoutException extends RuntimeException
+{
+    public function __construct(string $message, private readonly float $spentTime, private readonly float $timeout)
+    {
+        parent::__construct($message);
+    }
+
+    public function getTimeout(): float
+    {
+        return $this->timeout;
+    }
+
+    public function getSpentTime(): float
+    {
+        return $this->spentTime;
+    }
+}
diff --git a/src/Packer.php b/src/Packer.php
index ca261bf9..2f778f19 100644
--- a/src/Packer.php
+++ b/src/Packer.php
@@ -46,6 +46,8 @@ class Packer implements LoggerAwareInterface
 
     private bool $beStrictAboutItemOrdering = false;
 
+    protected ?TimeoutChecker $timeoutChecker = null;
+
     public function __construct()
     {
         $this->items = new ItemList();
@@ -136,6 +138,11 @@ public function setPackedBoxSorter(PackedBoxSorter $packedBoxSorter): void
         $this->packedBoxSorter = $packedBoxSorter;
     }
 
+    public function setTimeoutChecker(TimeoutChecker $timeoutChecker): void
+    {
+        $this->timeoutChecker = $timeoutChecker;
+    }
+
     public function throwOnUnpackableItem(bool $throwOnUnpackableItem): void
     {
         $this->throwOnUnpackableItem = $throwOnUnpackableItem;
@@ -160,12 +167,12 @@ public function getUnpackedItems(): ItemList
     public function pack(): PackedBoxList
     {
         $this->logger->log(LogLevel::INFO, '[PACKING STARTED]');
-
+        $this->timeoutChecker?->start();
         $packedBoxes = $this->doBasicPacking();
 
         // If we have multiple boxes, try and optimise/even-out weight distribution
         if (!$this->beStrictAboutItemOrdering && $packedBoxes->count() > 1 && $packedBoxes->count() <= $this->maxBoxesToBalanceWeight) {
-            $redistributor = new WeightRedistributor($this->boxes, $this->packedBoxSorter, $this->boxQuantitiesAvailable);
+            $redistributor = new WeightRedistributor($this->boxes, $this->packedBoxSorter, $this->boxQuantitiesAvailable, $this->timeoutChecker);
             $redistributor->setLogger($this->logger);
             $packedBoxes = $redistributor->redistributeWeight($packedBoxes);
         }
@@ -188,6 +195,7 @@ public function doBasicPacking(bool $enforceSingleBox = false): PackedBoxList
 
             // Loop through boxes starting with smallest, see what happens
             foreach ($this->getBoxList($enforceSingleBox) as $box) {
+                $this->timeoutChecker?->throwOnTimeout();
                 $volumePacker = new VolumePacker($box, $this->items);
                 $volumePacker->setLogger($this->logger);
                 $volumePacker->beStrictAboutItemOrdering($this->beStrictAboutItemOrdering);
@@ -232,6 +240,7 @@ public function doBasicPacking(bool $enforceSingleBox = false): PackedBoxList
     public function packAllPermutations(): array
     {
         $this->logger->log(LogLevel::INFO, '[PACKING STARTED (all permutations)]');
+        $this->timeoutChecker?->start();
 
         $boxQuantitiesAvailable = clone $this->boxQuantitiesAvailable;
 
@@ -252,6 +261,7 @@ public function packAllPermutations(): array
 
             $additionalPermutationsForThisPermutation = [];
             foreach ($this->boxes as $box) {
+                $this->timeoutChecker?->throwOnTimeout();
                 if ($remainingBoxQuantities[$box] > 0) {
                     $volumePacker = new VolumePacker($box, $wipPermutation['itemsLeft']);
                     $volumePacker->setLogger($this->logger);
diff --git a/src/TimeoutChecker.php b/src/TimeoutChecker.php
new file mode 100644
index 00000000..37504ab7
--- /dev/null
+++ b/src/TimeoutChecker.php
@@ -0,0 +1,24 @@
+<?php
+
+/**
+ * Box packing (3D bin packing, knapsack problem).
+ *
+ * @author Doug Wright
+ */
+declare(strict_types=1);
+
+namespace DVDoug\BoxPacker;
+
+use DVDoug\BoxPacker\Exception\TimeoutException;
+
+interface TimeoutChecker
+{
+    public function __construct(float $timeout);
+
+    public function start(?float $startTime = null): void;
+
+    /**
+     * @throws TimeoutException
+     */
+    public function throwOnTimeout(?float $currentTime = null, string $message = 'Exceeded the timeout'): void;
+}
diff --git a/src/WeightRedistributor.php b/src/WeightRedistributor.php
index de3aaa4e..a6b4f589 100644
--- a/src/WeightRedistributor.php
+++ b/src/WeightRedistributor.php
@@ -38,7 +38,8 @@ class WeightRedistributor implements LoggerAwareInterface
     public function __construct(
         private readonly BoxList $boxes,
         private readonly PackedBoxSorter $packedBoxSorter,
-        private WeakMap $boxQuantitiesAvailable
+        private WeakMap $boxQuantitiesAvailable,
+        private readonly ?TimeoutChecker $timeoutChecker,
     ) {
         $this->logger = new NullLogger();
     }
@@ -106,6 +107,7 @@ private function equaliseWeight(PackedBox &$boxA, PackedBox &$boxB, float $targe
         $underWeightBoxItems = $underWeightBox->items->asItemArray();
 
         foreach ($overWeightBoxItems as $key => $overWeightItem) {
+            $this->timeoutChecker?->throwOnTimeout();
             if (!self::wouldRepackActuallyHelp($overWeightBoxItems, $overWeightItem, $underWeightBoxItems, $targetWeight)) {
                 continue; // moving this item would harm more than help
             }
diff --git a/tests/PackerTest.php b/tests/PackerTest.php
index 1ebad8d3..fe1214d4 100644
--- a/tests/PackerTest.php
+++ b/tests/PackerTest.php
@@ -10,6 +10,7 @@
 namespace DVDoug\BoxPacker;
 
 use DVDoug\BoxPacker\Exception\NoBoxesAvailableException;
+use DVDoug\BoxPacker\Exception\TimeoutException;
 use DVDoug\BoxPacker\Test\ConstrainedPlacementByCountTestItem;
 use DVDoug\BoxPacker\Test\LimitedSupplyTestBox;
 use DVDoug\BoxPacker\Test\PackedBoxByReferenceSorter;
@@ -1457,4 +1458,39 @@ public function testIssue620(): void
 
         self::assertCount(6, $packedBoxes);
     }
+
+    public function testTimeoutException(): void
+    {
+        $this->expectException(TimeoutException::class);
+        $packer = new Packer();
+        $packer->setTimeoutChecker(new DefaultTimeoutChecker(3.0));
+
+        for ($i = 0; $i < 100; ++$i) {
+            $box = new TestBox(
+                reference: 'box ' . $i,
+                outerWidth: $i * 10,
+                outerLength: $i * 10,
+                outerDepth: $i * 10,
+                emptyWeight: 1,
+                innerWidth: $i * 10,
+                innerLength: $i * 10,
+                innerDepth: $i * 10,
+                maxWeight: 10000
+            );
+            $packer->addBox($box);
+        }
+
+        $item = new TestItem(
+            description: 'item 1',
+            width: 100,
+            length: 100,
+            depth: 100,
+            weight: 100,
+            allowedRotation: Rotation::BestFit
+        );
+        $packer->addItem($item, 500);
+
+        /** @var PackedBox[] $packedBoxes */
+        $packedBoxes = iterator_to_array($packer->pack(), false);
+    }
 }