diff --git a/main/src/com/google/refine/expr/functions/date/Inc.java b/main/src/com/google/refine/expr/functions/date/Inc.java
index 9ad1a1719..ff521d620 100644
--- a/main/src/com/google/refine/expr/functions/date/Inc.java
+++ b/main/src/com/google/refine/expr/functions/date/Inc.java
@@ -78,6 +78,10 @@ public class Inc implements Function {
             return ChronoUnit.WEEKS;
         } else if ("seconds".equals(unit) || "sec".equals(unit) || "s".equals(unit)) {
             return ChronoUnit.SECONDS;
+        } else if ("milliseconds".equals(unit) || "ms".equals(unit) || "S".equals(unit)) {
+            return ChronoUnit.MILLIS;
+        } else if ("nanos".equals(unit) || "nano".equals(unit) || "n".equals(unit)) {
+            return ChronoUnit.NANOS;
         } else {
             throw new RuntimeException("Unit '" + unit + "' not recognized.");
         }
diff --git a/main/src/com/google/refine/expr/functions/strings/Diff.java b/main/src/com/google/refine/expr/functions/strings/Diff.java
index 855b5a352..155b0bfea 100644
--- a/main/src/com/google/refine/expr/functions/strings/Diff.java
+++ b/main/src/com/google/refine/expr/functions/strings/Diff.java
@@ -60,7 +60,17 @@ public class Diff implements Function {
                             OffsetDateTime c1 = (OffsetDateTime)o1;
                             OffsetDateTime c2 = (OffsetDateTime)o2;
 
-                            long delta = (c1.toInstant().toEpochMilli() - c2.toInstant().toEpochMilli()) / 1000;
+                            long delta = getNano(c1) - getNano(c2);
+                            if ("nanos".equals(unit)) {
+                                return delta;
+                            }
+                            
+                            delta /= 1000;
+                            if ("milliseconds".equals(unit)) {
+                                return delta;
+                            }
+                            
+                            delta /= 1000000;
                             if ("seconds".equals(unit)) {
                                 return delta;
                             }
@@ -101,4 +111,8 @@ public class Diff implements Function {
         writer.key("returns"); writer.value("string for strings, number for dates");
         writer.endObject();
     }
+    
+    private long getNano(OffsetDateTime odt) {
+        return odt.toEpochSecond() * 1000000000l + odt.toInstant().getNano();
+    }
 }
diff --git a/main/tests/server/src/com/google/refine/tests/expr/functions/date/IncTests.java b/main/tests/server/src/com/google/refine/tests/expr/functions/date/IncTests.java
index c7b6608e9..e1905b5c0 100644
--- a/main/tests/server/src/com/google/refine/tests/expr/functions/date/IncTests.java
+++ b/main/tests/server/src/com/google/refine/tests/expr/functions/date/IncTests.java
@@ -101,6 +101,18 @@ public class IncTests extends RefineTest {
         Assert.assertEquals(invoke("inc",  source, 2, "sec"), source.plus(2, ChronoUnit.SECONDS));
         Assert.assertEquals(invoke("inc",  source, 2, "s"), source.plus(2, ChronoUnit.SECONDS));
         
+        // add milliseconds
+        Assert.assertTrue(invoke("inc",  source, 2, "milliseconds") instanceof OffsetDateTime);
+        Assert.assertEquals(invoke("inc",  source, 2, "milliseconds"), source.plus(2, ChronoUnit.MILLIS));
+        Assert.assertEquals(invoke("inc",  source, 2, "ms"), source.plus(2, ChronoUnit.MILLIS));
+        Assert.assertEquals(invoke("inc",  source, 2, "S"), source.plus(2, ChronoUnit.MILLIS));
+        
+        // add nanos
+        Assert.assertTrue(invoke("inc",  source, 2, "nanos") instanceof OffsetDateTime);
+        Assert.assertEquals(invoke("inc",  source, 2, "nanos"), source.plus(2, ChronoUnit.NANOS));
+        Assert.assertEquals(invoke("inc",  source, 2, "nano"), source.plus(2, ChronoUnit.NANOS));
+        Assert.assertEquals(invoke("inc",  source, 2, "n"), source.plus(2, ChronoUnit.NANOS));
+        
         // exception
         Assert.assertTrue(invoke("inc", source, 99) instanceof EvalError);
         Assert.assertTrue(invoke("inc", source.toInstant().toEpochMilli(), 99, "h") instanceof EvalError);
diff --git a/main/tests/server/src/com/google/refine/tests/expr/functions/strings/DiffTests.java b/main/tests/server/src/com/google/refine/tests/expr/functions/strings/DiffTests.java
index 7f98278fa..92f44c6c7 100644
--- a/main/tests/server/src/com/google/refine/tests/expr/functions/strings/DiffTests.java
+++ b/main/tests/server/src/com/google/refine/tests/expr/functions/strings/DiffTests.java
@@ -28,8 +28,8 @@ public class DiffTests extends RefineTest {
     @BeforeTest
     public void init() {
         logger = LoggerFactory.getLogger(this.getClass());
-        odt1 = OffsetDateTime.parse("2011-09-01T10:15:30+01:00", DateTimeFormatter.ISO_OFFSET_DATE_TIME);
-        odt2 = OffsetDateTime.parse("2011-12-02T10:16:30+01:00", DateTimeFormatter.ISO_OFFSET_DATE_TIME);
+        odt1 = OffsetDateTime.parse("2011-09-01T10:15:30.123456+01:00", DateTimeFormatter.ISO_OFFSET_DATE_TIME);
+        odt2 = OffsetDateTime.parse("2011-12-02T10:16:30.123467+01:00", DateTimeFormatter.ISO_OFFSET_DATE_TIME);
     }
     
     @BeforeMethod
@@ -77,5 +77,7 @@ public class DiffTests extends RefineTest {
         Assert.assertEquals(invoke("diff",odt2,odt1,"months"),Long.valueOf(3));
         Assert.assertEquals(invoke("diff",odt2,odt1,"hours"),Long.valueOf(2208));
         Assert.assertEquals(invoke("diff",odt2,odt1,"seconds"),Long.valueOf(7948860));
+        Assert.assertEquals(invoke("diff",odt2,odt1,"milliseconds"),Long.valueOf(7948860000011l));
+        Assert.assertEquals(invoke("diff",odt2,odt1,"nanos"),Long.valueOf(7948860000011000l));
     }
 }