diff --git a/apps/api/src/routes/book.ts b/apps/api/src/routes/book.ts
index e020754..3fb61c9 100644
--- a/apps/api/src/routes/book.ts
+++ b/apps/api/src/routes/book.ts
@@ -61,7 +61,7 @@ bookRouter.get("/availability", async (c) => {
   if (!service) return c.json({ error: "Service not found" }, 404);
 
   // Buffer-aware duration: extra time for large/x-large or complex coats
-  const extraBuffer = (petSizeCategory === "large" || petSizeCategory === "x-large")
+  const extraBuffer = (petSizeCategory === "large" || petSizeCategory === "xlarge")
     ? (service.defaultBufferMinutes ?? 0)
     : 0;
   const durationMinutes = service.durationMinutes + extraBuffer;
@@ -121,7 +121,7 @@ const bookingSchema = z.object({
   petSpecies: z.string().min(1).max(100),
   petBreed: z.string().max(100).optional(),
   petSizeCategory: z
-    .enum(["small", "medium", "large", "x-large"])
+    .enum(["small", "medium", "large", "xlarge"])
     .optional(),
   petCoatType: z
     .enum(["smooth", "double", "curly", "wire", "long", "hairless"])
@@ -213,7 +213,7 @@ bookRouter.post(
     if (!pet) return c.json({ error: "Failed to create pet" }, 500);
 
     // Buffer-aware end time: large/x-large pets add service bufferMinutes
-    if (body.petSizeCategory === "large" || body.petSizeCategory === "x-large") {
+    if (body.petSizeCategory === "large" || body.petSizeCategory === "xlarge") {
       end = new Date(start.getTime() + (service.durationMinutes + (service.defaultBufferMinutes ?? 0)) * 60_000);
     }