diff --git a/tests/Services/ProjectSystem/ProjectBuildHelperTest.php b/tests/Services/ProjectSystem/ProjectBuildHelperTest.php
index fb31b51e..cf36b030 100644
--- a/tests/Services/ProjectSystem/ProjectBuildHelperTest.php
+++ b/tests/Services/ProjectSystem/ProjectBuildHelperTest.php
@@ -26,7 +26,10 @@ use App\Entity\Parts\Part;
 use App\Entity\Parts\PartLot;
 use App\Entity\ProjectSystem\Project;
 use App\Entity\ProjectSystem\ProjectBOMEntry;
+use App\Entity\PriceInformations\Orderdetail;
+use App\Entity\PriceInformations\Pricedetail;
 use App\Services\ProjectSystem\ProjectBuildHelper;
+use Brick\Math\BigDecimal;
 use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;
 
 final class ProjectBuildHelperTest extends WebTestCase
@@ -130,6 +133,149 @@ final class ProjectBuildHelperTest extends WebTestCase
         $project->addBomEntry($bom_entry1);
 
         $this->assertSame('∞', $this->service->getMaximumBuildableCountAsString($project));
+    }
 
+    // --- Build price tests ---
+
+    private function makePartWithPrice(float $pricePerPiece, float $minQty = 1.0): Part
+    {
+        $part = new Part();
+        $orderdetail = new Orderdetail();
+        $pricedetail = (new Pricedetail())
+            ->setMinDiscountQuantity($minQty)
+            ->setPrice(BigDecimal::of((string) $pricePerPiece));
+        $orderdetail->addPricedetail($pricedetail);
+        $part->addOrderdetail($orderdetail);
+        return $part;
+    }
+
+    public function testCalculateTotalBuildPriceEmptyProject(): void
+    {
+        $project = new Project();
+        $this->assertNull($this->service->calculateTotalBuildPrice($project));
+    }
+
+    public function testCalculateTotalBuildPriceNoPricingData(): void
+    {
+        $project = new Project();
+        // Part with no orderdetails — no pricing
+        $entry = (new ProjectBOMEntry())->setPart(new Part())->setQuantity(2);
+        $project->addBomEntry($entry);
+
+        $this->assertNull($this->service->calculateTotalBuildPrice($project));
+    }
+
+    public function testCalculateTotalBuildPriceNonPartEntry(): void
+    {
+        $project = new Project();
+        $entry = new ProjectBOMEntry();
+        $entry->setName('Custom wire');
+        $entry->setQuantity(3);
+        $entry->setPrice(BigDecimal::of('2.00'));
+        $project->addBomEntry($entry);
+
+        // 3 × 2.00 = 6.00 for 1 build
+        $result = $this->service->calculateTotalBuildPrice($project, 1);
+        $this->assertNotNull($result);
+        $this->assertTrue(BigDecimal::of('6.00')->isEqualTo($result));
+    }
+
+    public function testCalculateTotalBuildPriceNonPartEntryMultipleBuilds(): void
+    {
+        $project = new Project();
+        $entry = new ProjectBOMEntry();
+        $entry->setName('Custom wire');
+        $entry->setQuantity(3);
+        $entry->setPrice(BigDecimal::of('2.00'));
+        $project->addBomEntry($entry);
+
+        // 3 × 2.00 × 5 = 30.00 for 5 builds
+        $result = $this->service->calculateTotalBuildPrice($project, 5);
+        $this->assertNotNull($result);
+        $this->assertTrue(BigDecimal::of('30.00')->isEqualTo($result));
+    }
+
+    public function testCalculateTotalBuildPriceWithPart(): void
+    {
+        $project = new Project();
+        $entry = new ProjectBOMEntry();
+        $entry->setPart($this->makePartWithPrice(1.50));
+        $entry->setQuantity(4);
+        $project->addBomEntry($entry);
+
+        // 4 × 1.50 = 6.00 for 1 build
+        $result = $this->service->calculateTotalBuildPrice($project, 1);
+        $this->assertNotNull($result);
+        $this->assertTrue(BigDecimal::of('6.00')->isEqualTo($result));
+    }
+
+    public function testCalculateUnitBuildPriceEqualsTotal(): void
+    {
+        $project = new Project();
+        $entry = new ProjectBOMEntry();
+        $entry->setName('Screw');
+        $entry->setQuantity(10);
+        $entry->setPrice(BigDecimal::of('0.10'));
+        $project->addBomEntry($entry);
+
+        // unit = 10 × 0.10 = 1.00; total for 3 builds = 3.00
+        $unit = $this->service->calculateUnitBuildPrice($project, 3);
+        $total = $this->service->calculateTotalBuildPrice($project, 3);
+        $this->assertNotNull($unit);
+        $this->assertNotNull($total);
+        $this->assertTrue($total->isEqualTo($unit->multipliedBy(3)));
+    }
+
+    public function testRoundedTotalBuildPriceRoundsUp(): void
+    {
+        $project = new Project();
+        $entry = new ProjectBOMEntry();
+        $entry->setName('Tiny part');
+        $entry->setQuantity(1);
+        $entry->setPrice(BigDecimal::of('0.001'));
+        $project->addBomEntry($entry);
+
+        // 0.001 rounded up to 2dp = 0.01
+        $result = $this->service->roundedTotalBuildPrice($project, 1);
+        $this->assertNotNull($result);
+        $this->assertTrue(BigDecimal::of('0.01')->isEqualTo($result));
+    }
+
+    public function testCalculateTotalBuildPriceMixedEntries(): void
+    {
+        $project = new Project();
+
+        // Part entry: 2 × 3.00 = 6.00
+        $partEntry = new ProjectBOMEntry();
+        $partEntry->setPart($this->makePartWithPrice(3.00));
+        $partEntry->setQuantity(2);
+        $project->addBomEntry($partEntry);
+
+        // Non-part entry with price: 5 × 1.00 = 5.00
+        $nonPartEntry = new ProjectBOMEntry();
+        $nonPartEntry->setName('Solder');
+        $nonPartEntry->setQuantity(5);
+        $nonPartEntry->setPrice(BigDecimal::of('1.00'));
+        $project->addBomEntry($nonPartEntry);
+
+        // Total = 11.00
+        $result = $this->service->calculateTotalBuildPrice($project, 1);
+        $this->assertNotNull($result);
+        $this->assertTrue(BigDecimal::of('11.00')->isEqualTo($result));
+    }
+
+    public function testCalculateTotalBuildPriceRespectsMinOrderAmount(): void
+    {
+        $project = new Project();
+        // Part has a minimum order quantity of 10 at 0.50/piece
+        $entry = new ProjectBOMEntry();
+        $entry->setPart($this->makePartWithPrice(0.50, 10.0));
+        $entry->setQuantity(1); // BOM only needs 1, but MOQ is 10
+        $project->addBomEntry($entry);
+
+        // Price lookup uses qty=10 (MOQ), returns 0.50. Cost = 1 × 0.50 = 0.50
+        $result = $this->service->calculateTotalBuildPrice($project, 1);
+        $this->assertNotNull($result);
+        $this->assertTrue(BigDecimal::of('0.50')->isEqualTo($result));
     }
 }