diff --git a/src/_zkapauthorizer/model.py b/src/_zkapauthorizer/model.py
index 4f8b051df0e0d4faafe93efedd1455344c98e1bf..4b2dd852030a6ddb4eef126c7f47a3ad4b40b553 100644
--- a/src/_zkapauthorizer/model.py
+++ b/src/_zkapauthorizer/model.py
@@ -558,6 +558,23 @@ class VoucherStore(object):
             in texts
         )
 
+    @with_cursor
+    def count_unblinded_tokens(self, cursor):
+        """
+        Return the largest number of unblinded tokens that can be requested from
+        ``get_unblinded_tokens`` without causing it to raise
+        ``NotEnoughTokens``.
+        """
+        cursor.execute(
+            """
+            SELECT count(1)
+            FROM   [unblinded-tokens]
+            WHERE  [token] NOT IN [in-use]
+            """,
+        )
+        (count,) = cursor.fetchone()
+        return count
+
     @with_cursor
     def discard_unblinded_tokens(self, cursor, unblinded_tokens):
         """
diff --git a/src/_zkapauthorizer/tests/test_model.py b/src/_zkapauthorizer/tests/test_model.py
index 6a0d4450f68f00818af4b10ddfaf3634f430a865..a2a8e5a125fc941942195f15534a63a78f28217d 100644
--- a/src/_zkapauthorizer/tests/test_model.py
+++ b/src/_zkapauthorizer/tests/test_model.py
@@ -739,14 +739,26 @@ class UnblindedTokenStoreTests(TestCase):
     )
     def test_unblinded_tokens_round_trip(self, get_config, now, voucher_value, public_key, completed, data):
         """
-        Unblinded tokens that are added to the store can later be retrieved.
+        Unblinded tokens that are added to the store can later be retrieved and counted.
         """
         random_tokens, unblinded_tokens = paired_tokens(data)
         store = self.useFixture(TemporaryVoucherStore(get_config, lambda: now)).store
         store.add(voucher_value, len(random_tokens), 0, lambda: random_tokens)
         store.insert_unblinded_tokens_for_voucher(voucher_value, public_key, unblinded_tokens, completed)
+
+        # All the tokens just inserted should be counted.
+        self.expectThat(
+            store.count_unblinded_tokens(),
+            Equals(len(unblinded_tokens)),
+        )
         retrieved_tokens = store.get_unblinded_tokens(len(random_tokens))
 
+        # All the tokens just extracted should not be counted.
+        self.expectThat(
+            store.count_unblinded_tokens(),
+            Equals(0),
+        )
+
         self.expectThat(
             set(unblinded_tokens),
             Equals(set(retrieved_tokens)),