diff --git a/l10n_us_hr_payroll/data/state/de_delaware.xml b/l10n_us_hr_payroll/data/state/de_delaware.xml
index fad2abf6..70965b3e 100644
--- a/l10n_us_hr_payroll/data/state/de_delaware.xml
+++ b/l10n_us_hr_payroll/data/state/de_delaware.xml
@@ -7,6 +7,7 @@
         <field name="country_id" ref="base.us"/>
     </record>
     <data noupdate="1">
+        <!-- Unchanged in 2021 https://laborfiles.delaware.gov/main/dui/handbook/UI%20Employer%20Handbook.pdf -->
         <record id="rule_parameter_us_de_suta_wage_base_2020" model="hr.rule.parameter.value">
             <field name="parameter_value">16500.0</field>
             <field name="rule_parameter_id" ref="rule_parameter_us_de_suta_wage_base"/>
@@ -21,6 +22,7 @@
         <field name="country_id" ref="base.us"/>
     </record>
     <data noupdate="1">
+        <!-- Unchanged in 2021 https://laborfiles.delaware.gov/main/dui/handbook/UI%20Employer%20Handbook.pdf -->
         <record id="rule_parameter_us_de_suta_rate_2020" model="hr.rule.parameter.value">
             <field name="parameter_value">1.50</field>
             <field name="rule_parameter_id" ref="rule_parameter_us_de_suta_rate"/>
@@ -34,6 +36,7 @@
         <field name="country_id" ref="base.us"/>
     </record>
     <data noupdate="1">
+        <!-- Unchanged in 2021 - Section 17 - https://revenue.delaware.gov/employers-guide-withholding-regulations-employers-duties/ -->
         <record id="rule_parameter_us_de_sit_tax_rate_2020" model="hr.rule.parameter.value">
             <field name="parameter_value">[
                 ( 2000,    0.0, 0.00),
@@ -56,6 +59,7 @@
         <field name="country_id" ref="base.us"/>
     </record>
     <data noupdate="1">
+        <!-- Unchanged in 2021 - Section 15 - https://revenue.delaware.gov/employers-guide-withholding-regulations-employers-duties/ -->
         <record id="rule_parameter_us_de_sit_standard_deduction_rate_2020" model="hr.rule.parameter.value">
             <field name="parameter_value">3250</field>
             <field name="rule_parameter_id" ref="rule_parameter_us_de_sit_standard_deduction_rate"/>
@@ -69,6 +73,7 @@
         <field name="country_id" ref="base.us"/>
     </record>
     <data noupdate="1">
+        <!-- Unchanged in 2021 - Section 15 - https://revenue.delaware.gov/employers-guide-withholding-regulations-employers-duties/ -->
         <record id="rule_parameter_us_de_sit_personal_exemption_rate_2020" model="hr.rule.parameter.value">
             <field name="parameter_value">110</field>
             <field name="rule_parameter_id" ref="rule_parameter_us_de_sit_personal_exemption_rate"/>
diff --git a/l10n_us_hr_payroll/tests/test_us_de_delaware_payslip_2020.py b/l10n_us_hr_payroll/tests/test_us_de_delaware_payslip_2020.py
index ed285368..75c0e755 100755
--- a/l10n_us_hr_payroll/tests/test_us_de_delaware_payslip_2020.py
+++ b/l10n_us_hr_payroll/tests/test_us_de_delaware_payslip_2020.py
@@ -30,7 +30,7 @@ class TestUsDEPayslip(TestUsPayslip):
 
     def test_2020_taxes_example(self):
         self._test_er_suta('DE', self.DE_UNEMP, date(2020, 1, 1), wage_base=self.DE_UNEMP_MAX_WAGE)
-        self._test_sit(480.77, 'single', 0.0, 1.0, 'weekly', date(2020, 1, 1), 13.88)
+        self._test_sit(480.77, 'single', 0.0, 1.0, 'weekly', date(2020, 1, 1), 13.84)
         self._test_sit(5000.0, 'single', 0.0, 2.0, 'monthly', date(2020, 1, 1), 211.93)
         self._test_sit(5000.0, 'single', 10.0, 1.0, 'monthly', date(2020, 1, 1), 231.1)
         self._test_sit(20000.0, 'married', 0.0, 3.0, 'quarterly', date(2020, 1, 1), 876.0)
diff --git a/l10n_us_hr_payroll/tests/test_us_de_delaware_payslip_2021.py b/l10n_us_hr_payroll/tests/test_us_de_delaware_payslip_2021.py
new file mode 100755
index 00000000..55ae8983
--- /dev/null
+++ b/l10n_us_hr_payroll/tests/test_us_de_delaware_payslip_2021.py
@@ -0,0 +1,36 @@
+# Part of Hibou Suite Professional. See LICENSE_PROFESSIONAL file for full copyright and licensing details.
+
+from datetime import date, timedelta
+from .common import TestUsPayslip
+
+
+class TestUsDEPayslip(TestUsPayslip):
+    ###
+    #   2021 Taxes and Rates
+    ###
+    DE_UNEMP_MAX_WAGE = 16500.0
+    DE_UNEMP = 1.50
+    # Calculation based on section 17. https://revenue.delaware.gov/employers-guide-withholding-regulations-employers-duties/
+
+    def _test_sit(self, wage, filing_status, additional_withholding, dependents, schedule_pay,  date_start, expected_withholding):
+        employee = self._createEmployee()
+        contract = self._createContract(employee,
+                                        wage=wage,
+                                        state_id=self.get_us_state('DE'),
+                                        de_w4_sit_filing_status=filing_status,
+                                        state_income_tax_additional_withholding=additional_withholding,
+                                        de_w4_sit_dependent=dependents,
+                                        schedule_pay=schedule_pay)
+        payslip = self._createPayslip(employee, date_start, date_start + timedelta(days=7))
+        payslip.compute_sheet()
+        cats = self._getCategories(payslip)
+
+        self._log('Computed period tax: ' + str(expected_withholding))
+        self.assertPayrollEqual(cats.get('EE_US_SIT', 0.0), -expected_withholding)
+
+    def test_2021_taxes_example(self):
+        self._test_er_suta('DE', self.DE_UNEMP, date(2021, 1, 1), wage_base=self.DE_UNEMP_MAX_WAGE)
+        self._test_sit(480.77, 'single', 0.0, 1.0, 'weekly', date(2021, 1, 1), 13.84)
+        self._test_sit(5000.0, 'single', 0.0, 2.0, 'monthly', date(2021, 1, 1), 211.93)
+        self._test_sit(5000.0, 'single', 10.0, 1.0, 'monthly', date(2021, 1, 1), 231.1)
+        self._test_sit(20000.0, 'married', 0.0, 3.0, 'quarterly', date(2021, 1, 1), 876.0)