diff --git a/src/calc/Calc.js b/src/calc/Calc.js
index 4e637da..da611ec 100644
--- a/src/calc/Calc.js
+++ b/src/calc/Calc.js
@@ -270,11 +270,18 @@ exports.relativeDate = function( data, value )
             // months
             case 'm':
                 date_new.setMonth( date_new.getMonth() + +tval );
+                // when adding a month to the last day of the month
+                // make sure the new date is also the last day of the month
+                // and not the first day of the next
+                if( date_new.getUTCDate() !== now_day )
+                {
+                    date_new.setUTCDate(0);
+                }
                 break;
 
             // days
             case 'd':
-                date_new.setDate( date_new.getUTCDate() + +tval );
+                date_new.setUTCDate( date_new.getUTCDate() + +tval );
                 break;
 
             // seconds
diff --git a/test/calc/CalcTest.js b/test/calc/CalcTest.js
new file mode 100644
index 0000000..dbec665
--- /dev/null
+++ b/test/calc/CalcTest.js
@@ -0,0 +1,72 @@
+/**
+ * Tests Calc
+ *
+ *  Copyright (C) 2017 R-T Specialty, LLC.
+ *
+ *  This file is part of liza.
+ *
+ *  liza is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+var liza         = require( '../..' ),
+    relativeDate = liza.calc.Calc.relativeDate,
+    expect       = require( 'chai' ).expect;
+
+
+describe( 'relativeDate', function()
+{
+    //returns a date relative to another date by adding a given value
+
+    it( 'assert 10 days is added, the date\'s month changes', function()
+    {
+        expect( relativeDate( ['2019-11-25'], ['10d'] ) )
+            .to.have.all.members( ['2019-12-05'] );
+    });
+
+    it( 'assert 10 days is added, the date\'s month and year changes', function()
+    {
+        expect( relativeDate( ['2019-12-28'], ['10d'] ) )
+            .to.have.all.members( ['2020-01-07'] );
+    });
+
+    it( 'assert edge case 6 months is added, the date does not go into the 7th month', function()
+    {
+        expect( relativeDate( ['2019-12-31'], ['6m'] ) )
+            .to.have.all.members( ['2020-06-30'] );
+    });
+
+    it( 'assert edge case 3 months is added, the date does not go into the 4th month', function()
+    {
+        expect( relativeDate( ['2019-08-31'], ['3m'] ) )
+            .to.have.all.members( ['2019-11-30'] );
+    });
+
+    it( 'assert 2 years is added', function()
+    {
+        expect( relativeDate( ['2019-12-31'], ['2y'] ) )
+            .to.have.all.members( ['2021-12-31'] );
+    });
+
+    it( 'assert edge case february', function()
+    {
+        expect( relativeDate( ['2018-12-31'], ['2m'] ) )
+            .to.have.all.members( ['2019-02-28'] );
+    });
+
+    it( 'assert edge case february leap year', function()
+    {
+        expect( relativeDate( ['2019-12-31'], ['2m'] ) )
+            .to.have.all.members( ['2020-02-29'] );
+    });
+});