diff --git a/app/Services/ReleasePlanner.php b/app/Services/ReleasePlanner.php
new file mode 100644
index 0000000..96f2e24
--- /dev/null
+++ b/app/Services/ReleasePlanner.php
@@ -0,0 +1,45 @@
+<?php
+
+namespace App\Services;
+
+/**
+ * Pure semver arithmetic for the Release page: given the current version, what beta-target versions
+ * may the operator cut? The dashboard computes the target X.Y.Z; the host bridge computes -betaN.
+ */
+class ReleasePlanner
+{
+    /**
+     * Proposed target versions (bare X.Y.Z) for the current version. A beta also offers continuing
+     * its own base (another beta of the same target).
+     *
+     * @return array{patch:string, minor:string, major:string, continueBeta?:string}
+     */
+    public function proposedTargets(string $current): array
+    {
+        $current = ltrim($current, 'vV');
+        $base = preg_replace('/-.*$/', '', $current);
+        [$maj, $min, $pat] = array_map('intval', array_pad(explode('.', (string) $base), 3, '0'));
+
+        $targets = [
+            'patch' => "{$maj}.{$min}.".($pat + 1),
+            'minor' => "{$maj}.".($min + 1).'.0',
+            'major' => ($maj + 1).'.0.0',
+        ];
+
+        if (str_contains($current, '-beta')) {
+            $targets['continueBeta'] = "{$maj}.{$min}.{$pat}";
+        }
+
+        return $targets;
+    }
+
+    /**
+     * The flat list of allowed target versions — the server-side allow-list for a posted target.
+     *
+     * @return array<int,string>
+     */
+    public function allowedTargets(string $current): array
+    {
+        return array_values($this->proposedTargets($current));
+    }
+}
diff --git a/tests/Unit/ReleasePlannerTest.php b/tests/Unit/ReleasePlannerTest.php
new file mode 100644
index 0000000..2469301
--- /dev/null
+++ b/tests/Unit/ReleasePlannerTest.php
@@ -0,0 +1,51 @@
+<?php
+
+namespace Tests\Unit;
+
+use App\Services\ReleasePlanner;
+use PHPUnit\Framework\TestCase;
+
+class ReleasePlannerTest extends TestCase
+{
+    private ReleasePlanner $planner;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->planner = new ReleasePlanner;
+    }
+
+    public function test_stable_version_offers_patch_minor_major_without_continue_beta(): void
+    {
+        $t = $this->planner->proposedTargets('0.9.58');
+
+        $this->assertSame('0.9.59', $t['patch']);
+        $this->assertSame('0.10.0', $t['minor']);
+        $this->assertSame('1.0.0', $t['major']);
+        $this->assertArrayNotHasKey('continueBeta', $t);
+    }
+
+    public function test_beta_version_also_offers_continue_beta_of_its_base(): void
+    {
+        $t = $this->planner->proposedTargets('0.10.0-beta3');
+
+        $this->assertSame('0.10.0', $t['continueBeta']);
+        $this->assertSame('0.10.1', $t['patch']);
+        $this->assertSame('0.11.0', $t['minor']);
+        $this->assertSame('1.0.0', $t['major']);
+    }
+
+    public function test_strips_a_leading_v(): void
+    {
+        $this->assertSame('0.9.59', $this->planner->proposedTargets('v0.9.58')['patch']);
+    }
+
+    public function test_allowed_targets_are_the_proposed_values(): void
+    {
+        $allowed = $this->planner->allowedTargets('0.10.0-beta1');
+
+        $this->assertContains('0.10.0', $allowed); // continueBeta
+        $this->assertContains('0.11.0', $allowed); // minor
+        $this->assertNotContains('0.9.0', $allowed);
+    }
+}