diff --git a/django/template/__init__.py b/django/template/__init__.py
index c5b8ba0b8f..503cfb77bf 100644
--- a/django/template/__init__.py
+++ b/django/template/__init__.py
@@ -445,16 +445,17 @@ class TokenParser(object):
             self.pointer = i
             return s
 
+# This only matches constant *strings* (things in quotes or marked for
+# translation). Numbers are treated as variables for implementation reasons
+# (so that they retain their type when passed to filters).
 constant_string = r"""
 (?:%(i18n_open)s%(strdq)s%(i18n_close)s|
 %(i18n_open)s%(strsq)s%(i18n_close)s|
 %(strdq)s|
-%(strsq)s)|
-%(num)s
+%(strsq)s)
 """ % {
     'strdq': r'"[^"\\]*(?:\\.[^"\\]*)*"', # double-quoted string
     'strsq': r"'[^'\\]*(?:\\.[^'\\]*)*'", # single-quoted string
-    'num': r'[-+\.]?\d[\d\.e]*', # numeric constant
     'i18n_open' : re.escape("_("),
     'i18n_close' : re.escape(")"),
     }
@@ -462,17 +463,18 @@ constant_string = constant_string.replace("\n", "")
 
 filter_raw_string = r"""
 ^(?P<constant>%(constant)s)|
-^(?P<var>[%(var_chars)s]+)|
+^(?P<var>[%(var_chars)s]+|%(num)s)|
  (?:%(filter_sep)s
      (?P<filter_name>\w+)
          (?:%(arg_sep)s
              (?:
               (?P<constant_arg>%(constant)s)|
-              (?P<var_arg>[%(var_chars)s]+)
+              (?P<var_arg>[%(var_chars)s]+|%(num)s)
              )
          )?
  )""" % {
     'constant': constant_string,
+    'num': r'[-+\.]?\d[\d\.e]*',
     'var_chars': "\w\." ,
     'filter_sep': re.escape(FILTER_SEPARATOR),
     'arg_sep': re.escape(FILTER_ARGUMENT_SEPARATOR),
diff --git a/tests/regressiontests/templates/custom.py b/tests/regressiontests/templates/custom.py
new file mode 100644
index 0000000000..e83b7dc736
--- /dev/null
+++ b/tests/regressiontests/templates/custom.py
@@ -0,0 +1,11 @@
+from django import test
+from django import template
+
+
+custom_filters = """
+>>> t = template.Template("{% load custom %}{{ string|trim:5 }}")
+>>> ctxt = template.Context({"string": "abcdefghijklmnopqrstuvwxyz"})
+>>> t.render(ctxt)
+u"abcde"
+"""
+
diff --git a/tests/regressiontests/templates/templatetags/__init__.py b/tests/regressiontests/templates/templatetags/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/regressiontests/templates/templatetags/custom.py b/tests/regressiontests/templates/templatetags/custom.py
new file mode 100644
index 0000000000..fdf8d1077f
--- /dev/null
+++ b/tests/regressiontests/templates/templatetags/custom.py
@@ -0,0 +1,11 @@
+from django import template
+from django.template.defaultfilters import stringfilter
+
+register = template.Library()
+
+def trim(value, num):
+    return value[:num]
+trim = stringfilter(trim)
+
+register.filter(trim)
+
diff --git a/tests/regressiontests/templates/tests.py b/tests/regressiontests/templates/tests.py
index 2211ac77be..f0eee526cc 100644
--- a/tests/regressiontests/templates/tests.py
+++ b/tests/regressiontests/templates/tests.py
@@ -18,9 +18,10 @@ from django.utils.translation import activate, deactivate, ugettext as _
 from django.utils.safestring import mark_safe
 from django.utils.tzinfo import LocalTimezone
 
-from unicode import unicode_tests
 from context import context_tests
+from custom import custom_filters
 from parser import filter_parsing, variable_parsing
+from unicode import unicode_tests
 
 try:
     from loaders import *
@@ -34,6 +35,7 @@ __test__ = {
     'unicode': unicode_tests,
     'context': context_tests,
     'filter_parsing': filter_parsing,
+    'custom_filters': custom_filters,
 }
 
 #################################