diff --git a/.gitignore b/.gitignore
index 9106b2a..d7516a4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,5 @@
 /pkg/
 /spec/reports/
 /tmp/
+/vendor/
+/Gemfile.lock
diff --git a/Rakefile b/Rakefile
index cd510a0..61c6d63 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,4 +1,8 @@
 # frozen_string_literal: true
 
 require "bundler/gem_tasks"
-task default: %i[]
+
+require "minitest/test_task"
+Minitest::TestTask.create
+
+task default: :test
diff --git a/lib/vat_rate.rb b/lib/vat_rate.rb
index 3c744d1..6431214 100644
--- a/lib/vat_rate.rb
+++ b/lib/vat_rate.rb
@@ -2,7 +2,50 @@
 
 require_relative "vat_rate/version"
 
-module VatRate
-  class Error < StandardError; end
-  # Your code goes here...
+require 'psych'
+require 'date'
+
+class VatRate
+  CATEGORIES = %i(standard parking reduced super_reduced)
+  RATES = Psych.safe_load_file(__dir__ + "/vat_rate.yml", permitted_classes: [Date])
+
+  def initialize(country:, category: :standard, date: Date.today, rate: nil)
+    raise ArgumentError unless CATEGORIES.include?(category)
+
+    @category = category
+    @country = country.to_s
+    @date = date
+
+    if rate
+      @rate = rate
+    elsif RATES["#{@category}_rates"].key?(@country)
+      @rate = RATES["#{@category}_rates"][@country].detect do |rate_data|
+        if rate
+          rate == rate_data['rate']
+        else
+          !rate_data.key?('from') || date.to_date >= rate_data['from']
+        end
+      end&.fetch('rate') || 0
+    else
+      @rate = 0
+    end
+  end
+
+  attr_reader :rate
+
+  def amount_with_vat(amount)
+    amount * (100 + @rate) / 100.0
+  end
+
+  def amount_without_vat(amount)
+    amount * 100.0 / (100 + @rate)
+  end
+
+  def vat_amount(amount, has_vat: false)
+    if has_vat
+      amount * @rate / (100.0 + @rate)
+    else
+      amount * @rate / 100.0
+    end
+  end
 end
diff --git a/lib/vat_rate.yml b/lib/vat_rate.yml
new file mode 100644
index 0000000..400a626
--- /dev/null
+++ b/lib/vat_rate.yml
@@ -0,0 +1,176 @@
+standard_rates:
+  AT:
+    - rate: 20
+  BE:
+    - rate: 21
+  BG:
+    - rate: 20
+  HR:
+    - rate: 25
+  CY:
+    - rate: 19
+  CZ:
+    - rate: 21
+  DK:
+    - rate: 25
+  EE:
+    - rate: 22
+  FI:
+    - rate: 24
+  FR:
+    - rate: 20
+      from: 2014-01-01
+    - rate: 19.6
+  DE:
+    - rate: 19
+  GR:
+    - rate: 24
+  HU:
+    - rate: 27
+  IS:
+    - rate: 24
+  IE:
+    - rate: 23
+  IT:
+    - rate: 22
+  LV:
+    - rate: 21
+  LT:
+    - rate: 21
+  LU:
+    - rate: 17
+  MT:
+    - rate: 18
+  NL:
+    - rate: 21
+  "NO":
+    - rate: 25
+  PL:
+    - rate: 23
+  PT:
+    - rate: 23
+  RO:
+    - rate: 19
+  SK:
+    - rate: 20
+  SI:
+    - rate: 22
+  ES:
+    - rate: 21
+  SE:
+    - rate: 25
+  CH:
+    - rate: 8.1
+  TR:
+    - rate: 20
+  GB:
+    - rate: 20
+parking_rates:
+  AT:
+    - rate: 13
+  BE:
+    - rate: 12
+  IE:
+    - rate: 13.5
+  LU:
+    - rate: 14
+  PT:
+    - rate: 13
+reduced_rates:
+  AT:
+    - rate: 10
+    - rate: 13
+  BE:
+    - rate: 6
+    - rate: 12
+  BG:
+    - rate: 9
+  HR:
+    - rate: 5
+    - rate: 13
+  CY:
+    - rate: 5
+    - rate: 9
+  CZ:
+    - rate: 12
+  EE:
+    - rate: 9
+  FI:
+    - rate: 10
+    - rate: 14
+  FR:
+    - rate: 5.5
+    - rate: 10
+  DE:
+    - rate: 7
+  GR:
+    - rate: 6
+    - rate: 13
+  HU:
+    - rate: 5
+    - rate: 18
+  IS:
+    - rate: 11
+  IE:
+    - rate: 9
+    - rate: 13.5
+  IT:
+    - rate: 5
+    - rate: 10
+  LV:
+    - rate: 5
+    - rate: 12
+  LT:
+    - rate: 5
+    - rate: 9
+  LU:
+    - rate: 8
+  MT:
+    - rate: 5
+    - rate: 7
+  NL:
+    - rate: 9
+  "NO":
+    - rate: 12
+    - rate: 15
+  PL:
+    - rate: 5
+    - rate: 8
+  PT:
+    - rate: 6
+    - rate: 13
+  RO:
+    - rate: 5
+    - rate: 9
+  SK:
+    - rate: 10
+  SI:
+    - rate: 5
+    - rate: 9.5
+  ES:
+    - rate: 10
+  SE:
+    - rate: 6
+    - rate: 12
+  CH:
+    - rate: 2.6
+    - rate: 3.8
+  TR:
+    - rate: 10
+  GB:
+    - rate: 5
+super_reduced_rates:
+  FR:
+    - rate: 2.1
+  IE:
+    - rate: 4.8
+  IT:
+    - rate: 4
+  LU:
+    - rate: 3
+  SK:
+    - rate: 5
+  ES:
+    - rate: 4
+  TR:
+    - rate: 1
diff --git a/lib/vat_rate/version.rb b/lib/vat_rate/version.rb
index 5499a87..8b8ce34 100644
--- a/lib/vat_rate/version.rb
+++ b/lib/vat_rate/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
-module VatRate
+class VatRate
   VERSION = "0.1.0"
 end
diff --git a/sig/vat_rate.rbs b/sig/vat_rate.rbs
deleted file mode 100644
index 1a68567..0000000
--- a/sig/vat_rate.rbs
+++ /dev/null
@@ -1,4 +0,0 @@
-module VatRate
-  VERSION: String
-  # See the writing guide of rbs: https://github.com/ruby/rbs#guides
-end
diff --git a/test/test_vat_rate.rb b/test/test_vat_rate.rb
new file mode 100644
index 0000000..bd89ef0
--- /dev/null
+++ b/test/test_vat_rate.rb
@@ -0,0 +1,43 @@
+require 'minitest/autorun'
+require 'vat_rate'
+
+class TestVatRate < Minitest::Test
+  def test_should_check_data
+    assert_kind_of Hash, VatRate::RATES
+
+    VatRate::CATEGORIES.each do |category|
+      VatRate::RATES["#{category}_rates"].each do |country, rates|
+        assert_kind_of String, country
+        assert_kind_of Array, rates
+        rates.each do |rate|
+          assert rate.key?('rate')
+          assert_kind_of Numeric, rate['rate']
+          assert_kind_of Date, rate['from'] if rate['from']
+        end
+      end
+    end
+  end
+
+  def test_should_initialize_rate
+    vat_rate = VatRate.new(country: :FR)
+    assert_equal 20, vat_rate.rate
+
+    vat_rate = VatRate.new(country: "FR")
+    assert_equal 20, vat_rate.rate
+  end
+
+  def test_should_get_correct_rate_for_date
+    vat_rate = VatRate.new(country: "FR", date: Date.new(2011))
+    assert_equal 19.6, vat_rate.rate
+  end
+
+  def test_should_get_amounts
+    vat_rate = VatRate.new(country: "FR")
+    assert_equal 20, vat_rate.rate
+    assert_equal 40, vat_rate.vat_amount(200)
+    assert_equal 40, vat_rate.vat_amount(200, has_vat: false)
+    assert_equal 40, vat_rate.vat_amount(240, has_vat: true)
+    assert_equal 240, vat_rate.amount_with_vat(200)
+    assert_equal 200, vat_rate.amount_without_vat(240)
+  end
+end
diff --git a/vat_rate.gemspec b/vat_rate.gemspec
index 0b7de77..c5c022c 100644
--- a/vat_rate.gemspec
+++ b/vat_rate.gemspec
@@ -8,16 +8,15 @@ Gem::Specification.new do |spec|
   spec.authors = ["Guillaume Dott"]
   spec.email = ["guillaume+github@dott.fr"]
 
-  spec.summary = "TODO: Write a short summary, because RubyGems requires one."
-  spec.description = "TODO: Write a longer description or delete this line."
-  spec.homepage = "TODO: Put your gem's website or public repo URL here."
+  spec.summary = "VAT rates and helper methods"
+  spec.homepage = "https://code.amnesix.eu/guillaume/vat_rate"
   spec.required_ruby_version = ">= 3.0.0"
 
-  spec.metadata["allowed_push_host"] = "TODO: Set to your gem server 'https://example.com'"
+  spec.metadata["allowed_push_host"] = "https://rubygems.org"
 
   spec.metadata["homepage_uri"] = spec.homepage
-  spec.metadata["source_code_uri"] = "TODO: Put your gem's public repo URL here."
-  spec.metadata["changelog_uri"] = "TODO: Put your gem's CHANGELOG.md URL here."
+  spec.metadata["source_code_uri"] = "https://code.amnesix.eu/guillaume/vat_rate"
+  spec.metadata["changelog_uri"] = "https://code.amnesix.eu/guillaume/vat_rate/src/branch/main/CHANGELOG.md"
 
   # Specify which files should be added to the gem when it is released.
   # The `git ls-files -z` loads the files in the RubyGem that have been added into git.
@@ -35,6 +34,8 @@ Gem::Specification.new do |spec|
   # Uncomment to register a new dependency of your gem
   # spec.add_dependency "example-gem", "~> 1.0"
 
+  spec.add_development_dependency "minitest"
+
   # For more information and examples about making a new gem, check out our
   # guide at: https://bundler.io/guides/creating_gem.html
 end