diff --git a/Gemfile.lock b/Gemfile.lock
index df66c8fa..041f3a88 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    active_storage_validations (1.1.0)
+    active_storage_validations (1.1.1)
       activejob (>= 5.2.0)
       activemodel (>= 5.2.0)
       activestorage (>= 5.2.0)
diff --git a/lib/active_storage_validations/matchers/size_validator_matcher.rb b/lib/active_storage_validations/matchers/size_validator_matcher.rb
index b234f978..6633a471 100644
--- a/lib/active_storage_validations/matchers/size_validator_matcher.rb
+++ b/lib/active_storage_validations/matchers/size_validator_matcher.rb
@@ -13,6 +13,7 @@ def initialize(attribute_name)
         @attribute_name = attribute_name
         @min = @max = nil
         @custom_message = nil
+        @context = nil
       end
 
       def description
@@ -49,6 +50,10 @@ def with_message(message)
         self
       end
 
+      def on(context)
+        @context = context
+      end
+
       def matches?(subject)
         @subject = subject.is_a?(Class) ? subject.new : subject
         responds_to_methods && not_lower_than_min? && higher_than_min? && lower_than_max? && not_higher_than_max?
@@ -86,11 +91,15 @@ def not_higher_than_max?
         @max.nil? || @max == Float::INFINITY || !passes_validation_with_size(@max + 1)
       end
 
+      def validate
+        @subject.validate(@context)
+      end
+
       def passes_validation_with_size(new_size)
         io = Tempfile.new('Hello world!')
         Matchers.stub_method(io, :size, new_size) do
           @subject.public_send(@attribute_name).attach(io: io, filename: 'test.png', content_type: 'image/pg')
-          @subject.validate
+          validate
           exclude_error_message = @custom_message || "file_size_not_"
           @subject.errors.details[@attribute_name].none? do |error|
             error[:error].to_s.include?(exclude_error_message)
diff --git a/lib/active_storage_validations/size_validator.rb b/lib/active_storage_validations/size_validator.rb
index 67b04350..49afa38d 100644
--- a/lib/active_storage_validations/size_validator.rb
+++ b/lib/active_storage_validations/size_validator.rb
@@ -31,7 +31,8 @@ def validate_each(record, attribute, _value)
         errors_options[:file_size] = number_to_human_size(file.blob.byte_size)
         errors_options[:min_size] = number_to_human_size(min_size(flat_options))
         errors_options[:max_size] = number_to_human_size(max_size(flat_options))
-        error_type = "file_size_not_#{flat_options.keys.first}".to_sym
+        keys = AVAILABLE_CHECKS & flat_options.keys
+        error_type = "file_size_not_#{keys.first}".to_sym
 
         add_error(record, attribute, error_type, **errors_options)
         break
diff --git a/test/dummy/app/models/size/portfolio.rb b/test/dummy/app/models/size/portfolio.rb
index 3f26b8ea..22baf32c 100644
--- a/test/dummy/app/models/size/portfolio.rb
+++ b/test/dummy/app/models/size/portfolio.rb
@@ -17,6 +17,8 @@ class Size::Portfolio < ApplicationRecord
   has_one_attached :size_greater_than_or_equal_to
   has_one_attached :size_between
   has_one_attached :size_with_message
+  has_one_attached :size_with_context
+  has_one_attached :size_with_if
 
   has_one_attached :proc_size_less_than
   has_one_attached :proc_size_less_than_or_equal_to
@@ -33,6 +35,8 @@ class Size::Portfolio < ApplicationRecord
   validates :size_greater_than_or_equal_to, size: { greater_than_or_equal_to: 7.kilobytes }
   validates :size_between, size: { between: 2.kilobytes..7.kilobytes }
   validates :size_with_message, size: { between: 2.kilobytes..7.kilobytes, message: 'is not in required file size range' }
+  validates :size_with_context, size: { less_than: 2.kilobytes }, on: :custom_context
+  validates :size_with_if, size: { less_than: 2.kilobytes }, if: -> {  title == 'very_nice_title' }
 
   validates :proc_size_less_than, size: { less_than: -> (record) { 2.kilobytes } }
   validates :proc_size_less_than_or_equal_to, size: { less_than_or_equal_to: -> (record) { 2.kilobytes } }
diff --git a/test/matchers/size_validator_matcher_test.rb b/test/matchers/size_validator_matcher_test.rb
index 1a3b6f80..075addaa 100644
--- a/test/matchers/size_validator_matcher_test.rb
+++ b/test/matchers/size_validator_matcher_test.rb
@@ -153,6 +153,14 @@ class UnknownAttachedAttribute < ActiveStorageValidations::Matchers::SizeValidat
     end
   end
 
+  class WithContextMatcher < ActiveStorageValidations::Matchers::SizeValidatorMatcher::Test
+    test 'matches when provided with the validation context' do
+      matcher = ActiveStorageValidations::Matchers::SizeValidatorMatcher.new(:size_with_context)
+      matcher.less_than 2.kilobytes
+      matcher.on(:custom_context)
+      assert matcher.matches?(Size::Portfolio)
+    end
+  end
 
   # Other tests
   test 'matches when provided with an instance' do
diff --git a/test/validators/size_validator_test.rb b/test/validators/size_validator_test.rb
index 4fd93e0b..9da7e117 100644
--- a/test/validators/size_validator_test.rb
+++ b/test/validators/size_validator_test.rb
@@ -239,6 +239,41 @@ def error_message
     end
   end
 
+  class WithContext < ActiveStorageValidations::SizeValidator::Test
+    # validates :size_with_context, size: { less_than: 2.kilobytes }, on: :custom_context
+
+    test 'generates correct error message' do
+      pt = Size::Portfolio.new(title: 'Matisse')
+      pt.size_with_context.attach(file_10ko)
+
+      refute pt.invalid?
+      refute pt.valid?(:custom_context)
+
+      assert_equal(
+        ['Size with context file size must be less than 2 KB (current size is 10 KB)'],
+        pt.errors.full_messages
+      )
+    end
+  end
+
+  class WithIf < ActiveStorageValidations::SizeValidator::Test
+    #   validates :size_with_if, size: { less_than: 2.kilobytes }, if: -> {  title == 'very_nice_title' }
+
+    test 'generates correct error message' do
+      pt = Size::Portfolio.new(title: 'Matisse')
+      pt.size_with_if.attach(file_10ko)
+
+      refute pt.invalid?
+
+      pt.title = 'very_nice_title'
+      refute pt.valid?
+
+      assert_equal(
+        ['Size with if file size must be less than 2 KB (current size is 10 KB)'],
+        pt.errors.full_messages
+      )
+    end
+  end
 end
 
 def file_1ko