diff --git a/ram/bookshelf/migrations/0006_alter_book_isbn.py b/ram/bookshelf/migrations/0006_alter_book_isbn.py
new file mode 100644
index 0000000..507823c
--- /dev/null
+++ b/ram/bookshelf/migrations/0006_alter_book_isbn.py
@@ -0,0 +1,18 @@
+# Generated by Django 4.2.5 on 2023-10-03 20:43
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("bookshelf", "0005_alter_book_options"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="book",
+            name="ISBN",
+            field=models.CharField(blank=True, max_length=17),
+        ),
+    ]
diff --git a/ram/bookshelf/models.py b/ram/bookshelf/models.py
index 31ba509..276a3ea 100644
--- a/ram/bookshelf/models.py
+++ b/ram/bookshelf/models.py
@@ -36,7 +36,7 @@ class Book(models.Model):
     title = models.CharField(max_length=200)
     authors = models.ManyToManyField(Author)
     publisher = models.ForeignKey(Publisher, on_delete=models.CASCADE)
-    ISBN = models.CharField(max_length=13, blank=True)
+    ISBN = models.CharField(max_length=17, blank=True)  # 13 + dashes
     language = models.CharField(
         max_length=7,
         choices=settings.LANGUAGES,