diff --git a/main/src/com/google/refine/expr/functions/date/DatePart.java b/main/src/com/google/refine/expr/functions/date/DatePart.java
index 126838c6d..d7440000c 100644
--- a/main/src/com/google/refine/expr/functions/date/DatePart.java
+++ b/main/src/com/google/refine/expr/functions/date/DatePart.java
@@ -36,6 +36,12 @@ package com.google.refine.expr.functions.date;
 import java.util.Calendar;
 import java.util.Date;
 import java.util.Properties;
+import java.util.TimeZone;
+import java.time.DayOfWeek;
+import java.time.LocalDate;
+import java.time.OffsetDateTime;
+import java.time.temporal.TemporalField;
+import java.time.temporal.WeekFields;
 
 import org.json.JSONException;
 import org.json.JSONWriter;
@@ -49,21 +55,62 @@ public class DatePart implements Function {
     @Override
     public Object call(Properties bindings, Object[] args) {
         if (args.length == 2 && 
-                args[0] != null && (args[0] instanceof Calendar || args[0] instanceof Date) && 
+                args[0] != null && (args[0] instanceof Calendar || args[0] instanceof Date || args[0] instanceof OffsetDateTime) && 
                 args[1] != null && args[1] instanceof String) {
             
             String part = (String) args[1];
             if (args[0] instanceof Calendar) {
                 return getPart((Calendar) args[0], part);
-            } else {
-                Calendar c = Calendar.getInstance();
+            } else if (args[0] instanceof Date) {
+                Calendar c = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
                 c.setTime((Date) args[0]);
                 return getPart(c, part);
+            } else {
+                return getPart((OffsetDateTime) args[0], part);
             }
         }
         return new EvalError(ControlFunctionRegistry.getFunctionName(this) + " expects a date and a string");
     }
     
+    private Object getPart(OffsetDateTime offsetDateTime, String part) {
+        if ("hours".equals(part) || "hour".equals(part) || "h".equals(part)) {
+            return offsetDateTime.getHour();
+        } else if ("minutes".equals(part) || "minute".equals(part) || "min".equals(part)) { // avoid 'm' to avoid confusion with month
+            return offsetDateTime.getMinute();
+        } else if ("seconds".equals(part) || "sec".equals(part) || "s".equals(part)) {
+            return offsetDateTime.getSecond();
+        } else if ("milliseconds".equals(part) || "ms".equals(part) || "S".equals(part)) {
+            return Math.round(offsetDateTime.getNano() / 1000);
+        } else if ("nanos".equals(part) || "nano".equals(part) || "n".equals(part)) {
+            // JSR-310 is based on nanoseconds, not milliseconds.
+            return offsetDateTime.getNano();
+        } else if ("years".equals(part) || "year".equals(part)) {
+            return offsetDateTime.getYear();
+        } else if ("months".equals(part) || "month".equals(part)) { // avoid 'm' to avoid confusion with minute
+            return offsetDateTime.getMonth().getValue();
+        } else if ("weeks".equals(part) || "week".equals(part) || "w".equals(part)) {
+            return getWeekOfMonth(offsetDateTime);
+        } else if ("days".equals(part) || "day".equals(part) || "d".equals(part)) {
+            return offsetDateTime.getDayOfMonth();
+        } else if ("weekday".equals(part)) {
+            return offsetDateTime.getDayOfWeek().name();
+        } else if ("time".equals(part)) {       // get Time In Millis
+            return offsetDateTime.toInstant().toEpochMilli();
+        } else {
+            return new EvalError("Date unit '" + part + "' not recognized.");
+        }
+    }
+
+    private int getWeekOfMonth(OffsetDateTime offsetDateTime) {
+        LocalDate date = offsetDateTime.toLocalDate();
+        DayOfWeek firstDayOfWeek = DayOfWeek.SUNDAY;
+        int minDays = 1;
+        WeekFields week = WeekFields.of(firstDayOfWeek, minDays);
+        TemporalField womField = week.weekOfMonth();
+        
+        return date.get(womField);
+    }
+    
     static private String[] s_daysOfWeek = new String[] {
         "Saturday", "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"
     };
diff --git a/main/tests/server/src/com/google/refine/tests/expr/functions/date/DatePartTests.java b/main/tests/server/src/com/google/refine/tests/expr/functions/date/DatePartTests.java
new file mode 100644
index 000000000..f4294fcd3
--- /dev/null
+++ b/main/tests/server/src/com/google/refine/tests/expr/functions/date/DatePartTests.java
@@ -0,0 +1,244 @@
+package com.google.refine.tests.expr.functions.date;
+
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.time.OffsetDateTime;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeFormatterBuilder;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.Properties;
+import java.util.TimeZone;
+
+import org.slf4j.LoggerFactory;
+import org.testng.Assert;
+import org.testng.annotations.AfterMethod;
+import org.testng.annotations.BeforeMethod;
+import org.testng.annotations.BeforeTest;
+import org.testng.annotations.Test;
+
+import com.google.refine.expr.EvalError;
+import com.google.refine.grel.ControlFunctionRegistry;
+import com.google.refine.grel.Function;
+import com.google.refine.tests.RefineTest;
+
+
+public class DatePartTests extends RefineTest {
+
+    static Properties bindings;
+    
+    @Override
+    @BeforeTest
+    public void init() {
+        logger = LoggerFactory.getLogger(this.getClass());
+    }
+    
+    @BeforeMethod
+    public void SetUp() {
+        bindings = new Properties();
+    }
+
+    @AfterMethod
+    public void TearDown() {
+        bindings = null;
+    }
+    
+    /**
+     * Lookup a control function by name and invoke it with a variable number of args
+     */
+    private static Object invoke(String name,Object... args) {
+        // registry uses static initializer, so no need to set it up
+        Function function = ControlFunctionRegistry.getFunction(name);
+        if (function == null) {
+            throw new IllegalArgumentException("Unknown function "+name);
+        }
+        if (args == null) {
+            return function.call(bindings,new Object[0]);
+        } else {
+            return function.call(bindings,args);
+        }
+    }
+    
+    @Test
+    public void testDateDatePart() throws ParseException {        
+        Assert.assertTrue(invoke("datePart") instanceof EvalError);
+        
+        // 2018-4-30 23:55:44, cannot use new Date(2018 - 1900, 4 - 1, 30, 23, 55, 44). use below way to get a UTC date:
+        SimpleDateFormat isoFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
+        isoFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
+        Date source = isoFormat.parse("2018-04-30T23:55:44");
+        
+        // hours
+        Assert.assertEquals(invoke("datePart", source, "hours"), 23);
+        Assert.assertEquals(invoke("datePart", source, "hour"), 23);
+        Assert.assertEquals(invoke("datePart", source, "h"), 23);
+        
+        // minutes
+        Assert.assertEquals(invoke("datePart", source, "minutes"), 55);
+        Assert.assertEquals(invoke("datePart", source, "minute"), 55);
+        Assert.assertEquals(invoke("datePart", source, "min"), 55);
+        
+        // seconds
+        Assert.assertEquals(invoke("datePart", source, "seconds"), 44);
+        Assert.assertEquals(invoke("datePart", source, "sec"), 44);
+        Assert.assertEquals(invoke("datePart", source, "s"), 44);
+        
+        // milliseconds
+        Assert.assertEquals(invoke("datePart", source, "milliseconds"), 0);
+        Assert.assertEquals(invoke("datePart", source, "ms"), 0);
+        Assert.assertEquals(invoke("datePart", source, "S"), 0);
+        
+        // years
+        Assert.assertEquals(invoke("datePart", source, "years"), 2018);
+        Assert.assertEquals(invoke("datePart", source, "year"), 2018);
+        
+        // months
+        Assert.assertEquals(invoke("datePart", source, "months"), 4);
+        Assert.assertEquals(invoke("datePart", source, "month"), 4);
+        
+        // weeks
+        Assert.assertEquals(invoke("datePart", source, "weeks"), 5);
+        Assert.assertEquals(invoke("datePart", source, "week"), 5);
+        Assert.assertEquals(invoke("datePart", source, "w"), 5);
+        
+        // days, day, d
+        Assert.assertEquals(invoke("datePart", source, "days"), 30);
+        Assert.assertEquals(invoke("datePart", source, "day"), 30);
+        Assert.assertEquals(invoke("datePart", source, "d"), 30);
+        
+        // weekday
+        Assert.assertEquals(invoke("datePart", source, "weekday"), "Monday");
+        
+        // time
+        Assert.assertEquals(invoke("datePart", source, "time"), 1525132544000l);
+    }
+    
+    @Test
+    public void testCalendarDatePart() throws ParseException {        
+     // 2018-4-30 23:55:44
+        SimpleDateFormat isoFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
+        isoFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
+        Date dt = isoFormat.parse("2018-04-30T23:55:44");
+        Calendar source = dateToCalendar(dt);
+        source.set(Calendar.MILLISECOND, 789);
+        
+        // hours
+        Assert.assertEquals(invoke("datePart", source, "hours"), 23);
+        Assert.assertEquals(invoke("datePart", source, "hour"), 23);
+        Assert.assertEquals(invoke("datePart", source, "h"), 23);
+        
+        // minutes
+        Assert.assertEquals(invoke("datePart", source, "minutes"), 55);
+        Assert.assertEquals(invoke("datePart", source, "minute"), 55);
+        Assert.assertEquals(invoke("datePart", source, "min"), 55);
+        
+        // seconds
+        Assert.assertEquals(invoke("datePart", source, "seconds"), 44);
+        Assert.assertEquals(invoke("datePart", source, "sec"), 44);
+        Assert.assertEquals(invoke("datePart", source, "s"), 44);
+        
+        // milliseconds
+        Assert.assertEquals(invoke("datePart", source, "milliseconds"), 789);
+        Assert.assertEquals(invoke("datePart", source, "ms"), 789);
+        Assert.assertEquals(invoke("datePart", source, "S"), 789);
+        
+        // years
+        Assert.assertEquals(invoke("datePart", source, "years"), 2018);
+        Assert.assertEquals(invoke("datePart", source, "year"), 2018);
+        
+        // months
+        Assert.assertEquals(invoke("datePart", source, "months"), 4);
+        Assert.assertEquals(invoke("datePart", source, "month"), 4);
+        
+        // weeks
+        Assert.assertEquals(invoke("datePart", source, "weeks"), 5);
+        Assert.assertEquals(invoke("datePart", source, "week"), 5);
+        Assert.assertEquals(invoke("datePart", source, "w"), 5);
+        
+        // days, day, d
+        Assert.assertEquals(invoke("datePart", source, "days"), 30);
+        Assert.assertEquals(invoke("datePart", source, "day"), 30);
+        Assert.assertEquals(invoke("datePart", source, "d"), 30);
+        
+        // weekday
+        Assert.assertEquals(invoke("datePart", source, "weekday"), "Monday");
+        
+        // time
+        Assert.assertEquals(invoke("datePart", source, "time"), 1525132544000l + 789);
+    }
+    
+    private DateTimeFormatter formatter = new DateTimeFormatterBuilder()
+            // here is the same as your code
+            .append(DateTimeFormatter.BASIC_ISO_DATE).appendLiteral('-')
+            // time (hour/minute/seconds)
+            .appendPattern("HH:mm:ss")
+            // optional nanos, with 9, 6 or 3 digits
+            .appendPattern("[.SSSSSSSSS][.SSSSSS][.SSS]")
+            // offset
+            .appendOffset("+HH:mm", "Z")
+            // create formatter
+            .toFormatter();
+    
+    @Test
+    public void testOffsetDateTimeDatePart() {        
+        // 2018-4-30 23:55:44
+        OffsetDateTime source = OffsetDateTime.parse("20180430-23:55:44.000789000Z",
+                formatter);
+        
+        // hours
+        Assert.assertEquals(invoke("datePart", source, "hours"), 23);
+        Assert.assertEquals(invoke("datePart", source, "hour"), 23);
+        Assert.assertEquals(invoke("datePart", source, "h"), 23);
+        
+        // minutes
+        Assert.assertEquals(invoke("datePart", source, "minutes"), 55);
+        Assert.assertEquals(invoke("datePart", source, "minute"), 55);
+        Assert.assertEquals(invoke("datePart", source, "min"), 55);
+        
+        // seconds
+        Assert.assertEquals(invoke("datePart", source, "seconds"), 44);
+        Assert.assertEquals(invoke("datePart", source, "sec"), 44);
+        Assert.assertEquals(invoke("datePart", source, "s"), 44);
+        
+        // milliseconds
+        Assert.assertEquals(invoke("datePart", source, "milliseconds"), 789);
+        Assert.assertEquals(invoke("datePart", source, "ms"), 789);
+        Assert.assertEquals(invoke("datePart", source, "S"), 789);
+        
+        // nanos
+        Assert.assertEquals(invoke("datePart", source, "nanos"), 789000);
+        Assert.assertEquals(invoke("datePart", source, "nano"), 789000);
+        Assert.assertEquals(invoke("datePart", source, "n"), 789000);
+        
+        // years
+        Assert.assertEquals(invoke("datePart", source, "years"), 2018);
+        Assert.assertEquals(invoke("datePart", source, "year"), 2018);
+        
+        // months
+        Assert.assertEquals(invoke("datePart", source, "months"), 4);
+        Assert.assertEquals(invoke("datePart", source, "month"), 4);
+        
+        // weeks
+        Assert.assertEquals(invoke("datePart", source, "weeks"), 5);
+        Assert.assertEquals(invoke("datePart", source, "week"), 5);
+        Assert.assertEquals(invoke("datePart", source, "w"), 5);
+        
+        // days, day, d
+        Assert.assertEquals(invoke("datePart", source, "days"), 30);
+        Assert.assertEquals(invoke("datePart", source, "day"), 30);
+        Assert.assertEquals(invoke("datePart", source, "d"), 30);
+        
+        // weekday
+        Assert.assertEquals(invoke("datePart", source, "weekday"), "MONDAY");
+        
+        // time
+        Assert.assertEquals(invoke("datePart", source, "time"), 1525132544000l);
+    }
+    
+    // Convert Date to Calendar
+    private Calendar dateToCalendar(Date date) {
+        Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
+        calendar.setTime(date);
+        return calendar;
+    }
+}