diff --git a/pre_commit_hooks/pretty_format_json.py b/pre_commit_hooks/pretty_format_json.py
index 9115077..fb1c487 100644
--- a/pre_commit_hooks/pretty_format_json.py
+++ b/pre_commit_hooks/pretty_format_json.py
@@ -33,24 +33,12 @@ def _autofix(filename, new_contents):
         f.write(new_contents)
 
 
-def parse_indent(s):
-    # type: (str) -> str
+def parse_num_to_int(s):
+    """Convert string numbers to int, leaving strings as is."""
     try:
-        int_indentation_spec = int(s)
+        return int(s)
     except ValueError:
-        if not s.strip():
-            return s
-        else:
-            raise ValueError(
-                'Non-whitespace JSON indentation delimiter supplied. ',
-            )
-    else:
-        if int_indentation_spec >= 0:
-            return int_indentation_spec * ' '
-        else:
-            raise ValueError(
-                'Negative integer supplied to construct JSON indentation delimiter. ',
-            )
+        return s
 
 
 def parse_topkeys(s):
@@ -68,9 +56,12 @@ def pretty_format_json(argv=None):
     )
     parser.add_argument(
         '--indent',
-        type=parse_indent,
-        default='  ',
-        help='String used as delimiter for one indentation level',
+        type=parse_num_to_int,
+        default='2',
+        help=(
+            'The number of indent spaces or a string to be used as delimiter'
+            ' for indentation level e.g. 4 or "\t" (Default: 2)'
+        ),
     )
     parser.add_argument(
         '--no-ensure-ascii',
diff --git a/tests/pretty_format_json_test.py b/tests/pretty_format_json_test.py
index 4054b4c..7ce7e16 100644
--- a/tests/pretty_format_json_test.py
+++ b/tests/pretty_format_json_test.py
@@ -3,20 +3,16 @@ import shutil
 import pytest
 from six import PY2
 
-from pre_commit_hooks.pretty_format_json import parse_indent
+from pre_commit_hooks.pretty_format_json import parse_num_to_int
 from pre_commit_hooks.pretty_format_json import pretty_format_json
 from testing.util import get_resource_path
 
 
-def test_parse_indent():
-    assert parse_indent('0') == ''
-    assert parse_indent('2') == '  '
-    assert parse_indent('\t') == '\t'
-    with pytest.raises(ValueError):
-        parse_indent('a')
-    with pytest.raises(ValueError):
-        parse_indent('-2')
-
+def test_parse_num_to_int():
+    assert parse_num_to_int('0') == 0
+    assert parse_num_to_int('2') == 2
+    assert parse_num_to_int('\t') == '\t'
+    assert parse_num_to_int('  ') == '  '
 
 
 @pytest.mark.parametrize(