diff --git a/src/box/fk_constraint.h b/src/box/fk_constraint.h
index fee82afb0e6f1e2a1d089c6e5599e955785292e9..b1e0cfb843d2caa56144d7583b5ccb65f4d52a4a 100644
--- a/src/box/fk_constraint.h
+++ b/src/box/fk_constraint.h
@@ -131,7 +131,7 @@ struct fk_constraint {
 static inline size_t
 fk_constraint_def_sizeof(uint32_t link_count, uint32_t name_len)
 {
-	return sizeof(struct fk_constraint) +
+	return sizeof(struct fk_constraint_def) +
 		link_count * sizeof(struct field_link) +
 		name_len + 1;
 }