diff --git a/python3/tests/test_parser.py b/python3/tests/test_parser.py
index a8db9fe..ccbf0f4 100644
--- a/python3/tests/test_parser.py
+++ b/python3/tests/test_parser.py
@@ -37,6 +37,7 @@ def test_parse_current(self):
         parse = parser('current')
         assert parse('1A') == 1
         assert parse('1mA') == mili
+        assert parse('1uA') == micro
         assert parse('1nA') == nano
         assert parse('1pA') == pico
 
@@ -64,6 +65,7 @@ def test_parse_inductance(self):
         parse = parser('inductance')
         assert parse('1H') == 1
         assert parse('1mH') == mili
+        assert parse('1uH') == micro
         assert parse('1nH') == nano
 
     def test_parse_frequency(self):
@@ -78,13 +80,14 @@ def test_parse_time(self):
         parse = parser('time')
         assert parse('1s') == 1
         assert parse('1ms') == mili
+        assert parse('1us') == micro
         assert parse('1ns') == nano
         assert parse('1ps') == pico
 
     def test_parse_temperature(self):
         parse = parser('temperature')
         assert parse('1C') == 1
-        assert parse('1°C')
+        assert parse('1°C') == 1
 
     def test_parse_tolerance(self):
         parse = parser('tolerance')
diff --git a/src/Units.g4 b/src/Units.g4
index 8ebeb93..e0a1b9d 100644
--- a/src/Units.g4
+++ b/src/Units.g4
@@ -61,6 +61,6 @@ frequency: NUMBER fprefix? HERZ tolerance?;
 fprefix: GIGA | MEGA | KILO;
 
 time: NUMBER tprefix? SECOND tolerance?;
-tprefix: MILI | NANO | PICO;
+tprefix: MILI | MICRO | NANO | PICO;
 
 temperature: NUMBER 'u{00b0}'? CELSIUS tolerance?;
\ No newline at end of file