diff --git a/chrono/datetime.cpp b/chrono/datetime.cpp
index 10da38b..41f5c85 100644
--- a/chrono/datetime.cpp
+++ b/chrono/datetime.cpp
@@ -119,6 +119,8 @@ DateTime DateTime::fromString(const char *str)
 std::pair<DateTime, TimeSpan> DateTime::fromIsoString(const char *str)
 {
     int values[9] = { 0 };
+    int *const yearIndex = values + 0;
+    int *const monthIndex = values + 1;
     int *const dayIndex = values + 2;
     int *const hourIndex = values + 3;
     int *const secondsIndex = values + 5;
@@ -178,7 +180,13 @@ std::pair<DateTime, TimeSpan> DateTime::fromIsoString(const char *str)
     if (deltaNegative) {
         delta = TimeSpan(-delta.totalTicks());
     }
-    return make_pair(DateTime::fromDateAndTime(values[0], values[1], *dayIndex, *hourIndex, values[4], *secondsIndex, miliSeconds), delta);
+    if (valueIndex < monthIndex && !*monthIndex) {
+        *monthIndex = 1;
+    }
+    if (valueIndex < dayIndex && !*dayIndex) {
+        *dayIndex = 1;
+    }
+    return make_pair(DateTime::fromDateAndTime(*yearIndex, *monthIndex, *dayIndex, *hourIndex, values[4], *secondsIndex, miliSeconds), delta);
 }
 
 /*!
diff --git a/tests/chronotests.cpp b/tests/chronotests.cpp
index df09521..65a9028 100644
--- a/tests/chronotests.cpp
+++ b/tests/chronotests.cpp
@@ -171,6 +171,9 @@ void ChronoTests::testDateTime()
     CPPUNIT_ASSERT_EQUAL(600, test5.first.nanosecond());
     CPPUNIT_ASSERT_EQUAL("2017-08-23T19:40:15.9850776-02:30"s, test5.first.toIsoString(test5.second));
     // test further variants
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("only year", DateTime::fromDate(2008), DateTime::fromIsoStringGmt("2008"));
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("only year and month", DateTime::fromDate(2008, 12), DateTime::fromIsoStringGmt("2008-12"));
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("only date", DateTime::fromDate(2008, 12, 5), DateTime::fromIsoStringGmt("2008-12-05"));
     CPPUNIT_ASSERT_EQUAL_MESSAGE("Zulu time", TimeSpan(), DateTime::fromIsoString("2017-08-23T19:40:15.985077682Z").second);
     CPPUNIT_ASSERT_EQUAL_MESSAGE("no minutes", TimeSpan::fromHours(3), DateTime::fromIsoString("2017-08-23T19:40:15.985077682+03").second);
     const auto test6 = DateTime::fromIsoString("1970-01-01T01:02:03+01:00");