diff --git a/include/re_hash.h b/include/re_hash.h
index f4c1209..60494ad 100644
--- a/include/re_hash.h
+++ b/include/re_hash.h
@@ -18,6 +18,7 @@ struct le *hash_apply(const struct hash *h, list_apply_h *ah, void *arg);
 struct list *hash_list(const struct hash *h, uint32_t key);
 uint32_t hash_bsize(const struct hash *h);
 void hash_flush(struct hash *h);
+uint32_t hash_valid_size(uint32_t size);
 
 
 /* Hash functions */
diff --git a/src/hash/hash.c b/src/hash/hash.c
index 15e7797..e07a87f 100644
--- a/src/hash/hash.c
+++ b/src/hash/hash.c
@@ -181,3 +181,20 @@ void hash_flush(struct hash *h)
 	for (i=0; i<h->bsize; i++)
 		list_flush(&h->bucket[i]);
 }
+
+
+/**
+ * Calculate a valid hash size from a random size
+ *
+ * @param size Requested size
+ *
+ * @return Valid hash size
+ */
+uint32_t hash_valid_size(uint32_t size)
+{
+	uint32_t x;
+
+	for (x=0; (uint32_t)1<<x < size && x < 31; x++);
+
+	return 1<<x;
+}