diff --git a/app/Services/PlanetService.php b/app/Services/PlanetService.php
index be6f38c..641e4b2 100644
--- a/app/Services/PlanetService.php
+++ b/app/Services/PlanetService.php
@@ -353,7 +353,17 @@ public function getPlanetImageType(): string
      */
     public function getPlanetFieldMax(): int
     {
-        return $this->planet->field_max;
+        $extra_fields = 0;
+        if ($this->planet->terraformer != 0) {
+            // For every level, it increases by 5
+            $extra_fields += $this->planet->terraformer * 5;
+
+            // For every 2 levels, it adds another bonus field
+            $two_level_bonus_count = (int)(floor($this->planet->terraformer / 2));
+            $extra_fields += $two_level_bonus_count;
+
+        }
+        return $extra_fields + $this->planet->field_max;
     }
 
     /**
diff --git a/tests/Unit/PlanetServiceTest.php b/tests/Unit/PlanetServiceTest.php
index c8a1210..1e2dcc4 100644
--- a/tests/Unit/PlanetServiceTest.php
+++ b/tests/Unit/PlanetServiceTest.php
@@ -115,13 +115,53 @@ public function testGetPlanetFieldMax(): void
         ]);
         $this->assertEquals(90, $this->planetService->getPlanetFieldMax());
 
-
         $this->createAndSetPlanetModel([
             'field_max' => 14,
         ]);
         $this->assertEquals(14, $this->planetService->getPlanetFieldMax());
     }
 
+    /**
+     * Test that the field max function with terraformer returns expected values
+     */
+    public function testGetPlanetFieldMaxWithTerraformer(): void
+    {
+        // Test none divisible by 2-- should only add 5.
+        $this->createAndSetPlanetModel([
+            'field_max' => 90,
+            'terraformer' => 1,
+        ]);
+
+        $this->assertEquals(95, $this->planetService->getPlanetFieldMax());
+
+        // Test a divisible of 2, should add 5, and +1 bonus.
+        $this->createAndSetPlanetModel([
+            'field_max' => 150,
+            'terraformer' => 2,
+        ]);
+
+        $this->assertEquals(161, $this->planetService->getPlanetFieldMax());
+
+        // Larger divisible
+        $this->createAndSetPlanetModel([
+            'field_max' => 100,
+            'terraformer' => 20,
+        ]);
+
+        // each level + 5 max fields - 100 base, plus 20*5 = 200
+        // every 2 levels + 1 max field- 20/2 = 10, so 200 + 10 = 210
+        $this->assertEquals(210, $this->planetService->getPlanetFieldMax());
+
+
+        // Ensure if it's not built it doesn't alter the max fields.
+        $this->createAndSetPlanetModel([
+            'field_max' => 100,
+            'terraformer' => 0,
+        ]);
+
+        $this->assertEquals(100, $this->planetService->getPlanetFieldMax());
+    }
+
     /**
      * Tests building count returns valid buildings, and specified levels.
      */