diff --git a/src/utils/__tests__/PhutilUtilsTestCase.php b/src/utils/__tests__/PhutilUtilsTestCase.php
--- a/src/utils/__tests__/PhutilUtilsTestCase.php
+++ b/src/utils/__tests__/PhutilUtilsTestCase.php
@@ -474,6 +474,8 @@
       '128 bits in bytes' => 16,
       '1 byte in bytes' => 1,
       '8 bits in bytes' => 1,
+      '1 minute in milliseconds' => 60000,
+      '2 minutes in microseconds' => 120000000,
     );
 
     foreach ($cases as $input => $expect) {
@@ -486,7 +488,6 @@
     $bad_cases = array(
       'quack',
       '3 years in seconds',
-      '1 minute in milliseconds',
       '1 day in days',
       '-1 minutes in seconds',
       '1.5 minutes in seconds',
diff --git a/src/utils/utils.php b/src/utils/utils.php
--- a/src/utils/utils.php
+++ b/src/utils/utils.php
@@ -1113,6 +1113,7 @@
               $src_unit));
       }
       break;
+
     case 'bytes':
       switch ($src_unit) {
         case 'byte':
@@ -1131,6 +1132,59 @@
               $src_unit));
       }
       break;
+
+    case 'milliseconds':
+      switch ($src_unit) {
+        case 'second':
+        case 'seconds':
+          $factor = 1000;
+          break;
+        case 'minute':
+        case 'minutes':
+          $factor = 1000 * 60;
+          break;
+        case 'hour':
+        case 'hours':
+          $factor = 1000 * 60 * 60;
+          break;
+        case 'day':
+        case 'days':
+          $factor = 1000 * 60 * 60 * 24;
+          break;
+        default:
+          throw new InvalidArgumentException(
+            pht(
+              'This function can not convert from the unit "%s".',
+              $src_unit));
+      }
+      break;
+
+    case 'microseconds':
+      switch ($src_unit) {
+        case 'second':
+        case 'seconds':
+          $factor = 1000000;
+          break;
+        case 'minute':
+        case 'minutes':
+          $factor = 1000000 * 60;
+          break;
+        case 'hour':
+        case 'hours':
+          $factor = 1000000 * 60 * 60;
+          break;
+        case 'day':
+        case 'days':
+          $factor = 1000000 * 60 * 60 * 24;
+          break;
+        default:
+          throw new InvalidArgumentException(
+            pht(
+              'This function can not convert from the unit "%s".',
+              $src_unit));
+      }
+      break;
+
     default:
       throw new InvalidArgumentException(
         pht(