diff --git a/lib/paperclip.rb b/lib/paperclip.rb
index a7cca24..bd06881 100644
--- a/lib/paperclip.rb
+++ b/lib/paperclip.rb
@@ -35,6 +35,7 @@ require 'paperclip/processor'
 require 'paperclip/thumbnail'
 require 'paperclip/recursive_thumbnail'
 require 'paperclip/storage'
+require 'paperclip/interpolations/plural_cache'
 require 'paperclip/interpolations'
 require 'paperclip/attachment'
 require 'paperclip/optimizer'
diff --git a/lib/paperclip/interpolations.rb b/lib/paperclip/interpolations.rb
index 42bf6a6..d35ae6c 100644
--- a/lib/paperclip/interpolations.rb
+++ b/lib/paperclip/interpolations.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Paperclip
   # This module contains all the methods that are available for interpolation
   # in paths and urls. To add your own (or override an existing one), you
@@ -6,13 +8,14 @@ module Paperclip
   module Interpolations
     extend self
 
-    # Hash assignment of interpolations. Included only for compatability,
+    # Hash assignment of interpolations. Included only for compatibility,
     # and is not intended for normal use.
     def self.[]= name, block
       define_method(name, &block)
+      @interpolators_cache = nil
     end
 
-    # Hash access of interpolations. Included only for compatability,
+    # Hash access of interpolations. Included only for compatibility,
     # and is not intended for normal use.
     def self.[] name
       method(name)
@@ -20,17 +23,28 @@ module Paperclip
 
     # Returns a sorted list of all interpolations.
     def self.all
-      self.instance_methods(false).sort
+      self.instance_methods(false).sort!
     end
 
     # Perform the actual interpolation. Takes the pattern to interpolate
     # and the arguments to pass, which are the attachment and style name.
+    # You can pass a method name on your record as a symbol, which should turn
+    # an interpolation pattern for Paperclip to use.
     def self.interpolate pattern, *args
-      all.reverse.inject( pattern.dup ) do |result, tag|
-        result.gsub(/:#{tag}/) do |match|
-          send( tag, *args )
-        end
+      pattern = args.first.instance.send(pattern) if pattern.kind_of? Symbol
+      result = pattern.dup
+      interpolators_cache.each do |method, token|
+        result.gsub!(token) { send(method, *args) } if result.include?(token)
       end
+      result
+    end
+
+    def self.interpolators_cache
+      @interpolators_cache ||= all.reverse!.map! { |method| [method, ":#{method}"] }
+    end
+
+    def self.plural_cache
+      @plural_cache ||= PluralCache.new
     end
 
     # Returns the filename, the same way as ":basename.:extension" would.
@@ -63,13 +77,16 @@ module Paperclip
 
     # Returns the underscored, pluralized version of the class name.
     # e.g. "users" for the User class.
-    def class attachment, style_name
-      attachment.instance.class.to_s.underscore.pluralize
+    # NOTE: The arguments need to be optional, because some tools fetch
+    # all class names. Calling #class will return the expected class.
+    def class attachment = nil, style_name = nil
+      return super() if attachment.nil? && style_name.nil?
+      plural_cache.underscore_and_pluralize_class(attachment.instance.class)
     end
 
     # Returns the basename of the file. e.g. "file" for "file.jpg"
     def basename attachment, style_name
-      attachment.original_filename.gsub(/#{File.extname(attachment.original_filename)}$/, "")
+      File.basename(attachment.original_filename, ".*")
     end
 
     # Returns the extension of the file. e.g. "jpg" for "file.jpg"
@@ -94,7 +111,7 @@ module Paperclip
     # Returns the pluralized form of the attachment name. e.g.
     # "avatars" for an attachment of :avatar
     def attachment attachment, style_name
-      attachment.name.to_s.downcase.pluralize
+      plural_cache.pluralize_symbol(attachment.name)
     end
 
     # Returns the style, or the default style if nil is supplied.
diff --git a/lib/paperclip/interpolations/plural_cache.rb b/lib/paperclip/interpolations/plural_cache.rb
new file mode 100644
index 0000000..23bd39f
--- /dev/null
+++ b/lib/paperclip/interpolations/plural_cache.rb
@@ -0,0 +1,18 @@
+module Paperclip
+  module Interpolations
+    class PluralCache
+      def initialize
+        @symbol_cache = {}.compare_by_identity
+        @klass_cache = {}.compare_by_identity
+      end
+
+      def pluralize_symbol(symbol)
+        @symbol_cache[symbol] ||= symbol.to_s.downcase.pluralize
+      end
+
+      def underscore_and_pluralize_class(klass)
+        @klass_cache[klass] ||= klass.name.underscore.pluralize
+      end
+    end
+  end
+end
diff --git a/test/plural_cache_test.rb b/test/plural_cache_test.rb
new file mode 100644
index 0000000..0e9a1d0
--- /dev/null
+++ b/test/plural_cache_test.rb
@@ -0,0 +1,34 @@
+require 'test_helper'
+
+class PluralCacheTest < Test::Unit::TestCase
+  should 'cache pluralizations' do
+    cache = Paperclip::Interpolations::PluralCache.new
+    symbol = :box
+
+    first = cache.pluralize_symbol(symbol)
+    second = cache.pluralize_symbol(symbol)
+    assert_equal first, second
+  end
+
+  should 'cache pluralizations and underscores' do
+    class BigBox ; end
+    cache = Paperclip::Interpolations::PluralCache.new
+    klass = BigBox
+
+    first = cache.underscore_and_pluralize_class(klass)
+    second = cache.underscore_and_pluralize_class(klass)
+    assert_equal first, second
+  end
+
+  should 'pluralize words' do
+    cache = Paperclip::Interpolations::PluralCache.new
+    assert_equal 'boxes', cache.pluralize_symbol(:box)
+  end
+
+  should 'pluralize and underscore words' do
+    class BigBox ; end
+    cache = Paperclip::Interpolations::PluralCache.new
+    klass = BigBox
+    assert_equal 'plural_cache_test/big_boxes', cache.underscore_and_pluralize_class(klass)
+  end
+end