diff --git a/docs/ref/contrib/postgres/fields.txt b/docs/ref/contrib/postgres/fields.txt
index 80b63b9260..0c89a22749 100644
--- a/docs/ref/contrib/postgres/fields.txt
+++ b/docs/ref/contrib/postgres/fields.txt
@@ -586,7 +586,7 @@ suitable for.
 All of the range fields translate to :ref:`psycopg2 Range objects
 <psycopg2:adapt-range>` in python, but also accept tuples as input if no bounds
 information is necessary. The default is lower bound included, upper bound
-excluded.
+excluded; that is, ``[)``.
 
 ``IntegerRangeField``
 ---------------------
@@ -598,6 +598,10 @@ excluded.
     the database and a :class:`~psycopg2:psycopg2.extras.NumericRange` in
     Python.
 
+    Regardless of the bounds specified when saving the data, PostgreSQL always
+    returns a range in a canonical form that includes the lower bound and
+    excludes the upper bound; that is ``[)``.
+
 ``BigIntegerRangeField``
 ------------------------
 
@@ -608,6 +612,10 @@ excluded.
     in the database and a :class:`~psycopg2:psycopg2.extras.NumericRange` in
     Python.
 
+    Regardless of the bounds specified when saving the data, PostgreSQL always
+    returns a range in a canonical form that includes the lower bound and
+    excludes the upper bound; that is ``[)``.
+
 ``FloatRangeField``
 -------------------
 
@@ -636,6 +644,10 @@ excluded.
     :class:`~django.db.models.DateField`. Represented by a ``daterange`` in the
     database and a :class:`~psycopg2:psycopg2.extras.DateRange` in Python.
 
+    Regardless of the bounds specified when saving the data, PostgreSQL always
+    returns a range in a canonical form that includes the lower bound and
+    excludes the upper bound; that is ``[)``.
+
 Querying Range Fields
 ---------------------