diff --git a/datasette/templates/_table.html b/datasette/templates/_table.html
index d91a1a57..5332f831 100644
--- a/datasette/templates/_table.html
+++ b/datasette/templates/_table.html
@@ -4,7 +4,7 @@
         <thead>
             <tr>
                 {% for column in display_columns %}
-                    <th {% if column.description %}data-column-description="{{ column.description }}" {% endif %}class="col-{{ column.name|to_css_class }}" scope="col" data-column="{{ column.name }}" data-column-type="{{ column.type }}" data-column-not-null="{{ column.notnull }}" data-is-pk="{% if column.is_pk %}1{% else %}0{% endif %}">
+                    <th {% if column.description %}data-column-description="{{ column.description }}" {% endif %}class="col-{{ column.name|to_css_class }}" scope="col" data-column="{{ column.name }}" data-column-type="{{ column.type.lower() }}" data-column-not-null="{{ column.notnull }}" data-is-pk="{% if column.is_pk %}1{% else %}0{% endif %}">
                         {% if not column.sortable %}
                             {{ column.name }}
                         {% else %}
diff --git a/tests/test_internals_database.py b/tests/test_internals_database.py
index bcecb486..31538a24 100644
--- a/tests/test_internals_database.py
+++ b/tests/test_internals_database.py
@@ -279,7 +279,15 @@ async def test_table_columns(db, table, expected):
 @pytest.mark.asyncio
 async def test_table_column_details(db, table, expected):
     columns = await db.table_column_details(table)
-    assert columns == expected
+    # Convert "type" to lowercase before comparison
+    # https://github.com/simonw/datasette/issues/1647
+    compare_columns = [
+        Column(
+            c.cid, c.name, c.type.lower(), c.notnull, c.default_value, c.is_pk, c.hidden
+        )
+        for c in columns
+    ]
+    assert compare_columns == expected
 
 
 @pytest.mark.asyncio