1diff --git a/src/RawFormulas/Date.ts b/src/RawFormulas/Date.ts
  2index fbfd05b..4d264d7 100644
  3--- a/src/RawFormulas/Date.ts
  4+++ b/src/RawFormulas/Date.ts
  5@@ -122,6 +122,51 @@ var DATEVALUE = function (...values) : number {
  6     }
  7   }
  8 
  9+  // Check YYYY/MM/DD HH(am|pm)
 10+  if (m === undefined) {
 11+    // For reference: https://regex101.com/r/m8FSCr/6
 12+    var matches = dateString.match(/^\s*(([0-9][0-9][0-9][0-9])|([1-9][0-9][0-9]))\/([1-9]|0[1-9]|1[0-2])\/([1-9]|[0-2][0-9]|3[0-1])\s*([0-9]|0[0-9]|1[0-2])\s*(am|pm)\s*$/i);
 13+    if (matches && matches.length === 8) {
 14+      var years = parseInt(matches[1]);
 15+      var months = parseInt(matches[4]) - 1; // Months are zero indexed.
 16+      var days = parseInt(matches[5]) - 1;// Months are zero indexed.
 17+      var actualYear = years;
 18+      if (years >= 0 && years < 30) {
 19+        actualYear = Y2K_YEAR + years;
 20+      } else if (years >= 30 && years < 100) {
 21+        actualYear = FIRST_YEAR + years;
 22+      }
 23+      var tmpMoment = moment([actualYear])
 24+        .add(months, 'months');
 25+      // If we're specifying more days than there are in this month
 26+      if (days > tmpMoment.daysInMonth() - 1) {
 27+        throw new CellError(VALUE_ERROR, "DATEVALUE parameter '" + dateString + "' cannot be parsed to date/time.");
 28+      }
 29+      tmpMoment = tmpMoment.add(days, 'days');
 30+      m = tmpMoment;
 31+    }
 32+  }
 33+
 34+  // Check YYYY/MM/DD HH:mm
 35+  if (m === undefined) {
 36+    // TODO: This.
 37+  }
 38+
 39+  // Check YYYY/MM/DD HH:mm(am|pm)
 40+  if (m === undefined) {
 41+    // TODO: This.
 42+  }
 43+
 44+  // Check YYYY/MM/DD HH:mm:ss
 45+  if (m === undefined) {
 46+    // TODO: This.
 47+  }
 48+
 49+  // Check YYYY/MM/DD HH:mm:ss(am|pm)
 50+  if (m === undefined) {
 51+    // TODO: This.
 52+  }
 53+
 54   // If we've not been able to parse the date by now, then we cannot parse it at all.
 55   if (m === undefined || !m.isValid()) {
 56     throw new CellError(VALUE_ERROR, "DATEVALUE parameter '" + dateString + "' cannot be parsed to date/time.");
 57diff --git a/tests/FormulasTest.ts b/tests/FormulasTest.ts
 58index 28691d0..91f6ac8 100644
 59--- a/tests/FormulasTest.ts
 60+++ b/tests/FormulasTest.ts
 61@@ -864,6 +864,55 @@ catchAndAssertEquals(function() {
 62 catchAndAssertEquals(function() {
 63   DATEVALUE("2005/1/44");// Out of range day for any month
 64 }, ERRORS.VALUE_ERROR);
 65+// YYYY/MM/DD HH(am|pm)
 66+assertEquals(DATEVALUE("1992/6/24 00am"), 33779);
 67+assertEquals(DATEVALUE("1992/06/24 01am "), 33779);
 68+assertEquals(DATEVALUE("1999/1/01 02pm"), 36161);
 69+assertEquals(DATEVALUE("2222/1/01 03pm"), 117610);
 70+assertEquals(DATEVALUE("1902/9/02 12pm"), 976);
 71+assertEquals(DATEVALUE("1902/9/2 12pm"), 976);
 72+assertEquals(DATEVALUE("4243/11/3 12pm   "), 856071);
 73+assertEquals(DATEVALUE("  1992/04/19   12pm   "), 33713);
 74+assertEquals(DATEVALUE("1992/5/20 01am"), 33744);
 75+assertEquals(DATEVALUE("1992/6/21  3pm"), 33776);
 76+assertEquals(DATEVALUE("1992/9/29 3pm"), 33876);
 77+assertEquals(DATEVALUE("1992/1/24 3pm"), 33627);
 78+assertEquals(DATEVALUE("1992/12/21 3pm"), 33959);
 79+assertEquals(DATEVALUE("1992/01/31 3pm"), 33634);
 80+assertEquals(DATEVALUE("1992/1/13 3pm"), 33616);
 81+assertEquals(DATEVALUE("2004/2/29 3pm"), 38046);
 82+assertEquals(DATEVALUE("2004/2/28  3pm "), 38045);
 83+assertEquals(DATEVALUE("1999/1/13 3pm"), 36173);
 84+assertEquals(DATEVALUE("1999/01/13 3pm"), 36173);
 85+assertEquals(DATEVALUE("0999/01/13 3pm"), -329069);
 86+assertEquals(DATEVALUE("1200/01/13 3pm"), -255656);
 87+assertEquals(DATEVALUE("0029/01/13 3pm"), 47131);
 88+assertEquals(DATEVALUE("0030/01/13 3pm"), 10971);
 89+assertEquals(DATEVALUE("0044/01/13 3pm"), 16084);
 90+assertEquals(DATEVALUE("0050/01/13 3pm"), 18276);
 91+assertEquals(DATEVALUE("0097/01/13 00pm"), 35443);
 92+assertEquals(DATEVALUE("0099/01/13 3pm"), 36173);
 93+assertEquals(DATEVALUE("0000/01/13 3pm"), 36538);
 94+assertEquals(DATEVALUE("0101/01/13 3pm"), -657057);
 95+assertEquals(DATEVALUE("0100/01/13 3pm"), -657422);
 96+assertEquals(DATEVALUE("100/12/31 3pm"), -657070);
 97+assertEquals(DATEVALUE("122/11/10 3pm"), -649086);
 98+assertEquals(DATEVALUE("2222/1/22 3pm"), 117631);
 99+assertEquals(DATEVALUE("222/1/22 3pm"), -612854);
100+catchAndAssertEquals(function() {
101+  DATEVALUE("2005/2/29 000pm");// Too many digits
102+}, ERRORS.VALUE_ERROR);
103+catchAndAssertEquals(function() {
104+  DATEVALUE("2001/2/2 13pm");// Hour out of range
105+}, ERRORS.VALUE_ERROR);
106+catchAndAssertEquals(function() {
107+  DATEVALUE("2005/2/29 11am");// Leap day on non-leap year.
108+}, ERRORS.VALUE_ERROR);
109+catchAndAssertEquals(function() {
110+  DATEVALUE("2005/1/44 11am");// Out of range day for any month
111+}, ERRORS.VALUE_ERROR);
112+
113+
114 // // yyyy-m-d
115 // assertEquals(DATEVALUE("1992-6-24"), 33779);
116 // assertEquals(DATEVALUE("1992-06-24"), 33779);