diff --git a/lib/DDG/Goodie/Timer.pm b/lib/DDG/Goodie/Timer.pm
index a2319f19d..a1ca149d4 100644
--- a/lib/DDG/Goodie/Timer.pm
+++ b/lib/DDG/Goodie/Timer.pm
@@ -8,7 +8,7 @@ zci answer_type => 'timer';
 zci is_cached   => 1;
 
 my @triggers = ('timer', 'countdown', 'count down', 'alarm', 'reminder');
-# Triggers that are vaild, but not stripped from the resulting query
+# Triggers that are valid, but not stripped from the resulting query
 my @nonStrippedTriggers = qw(minutes mins seconds secs hours hrs);
 # Triggers that are valid in start only
 my @baseTriggers = qw(start begin set run);
@@ -20,7 +20,7 @@ push(@startTriggers, @baseTriggers);
 # Beautifies the trigger can be appended in front/back of trigger
 my @beautifierTriggers = qw(online);
 #Joins the Timer Value
-my @joiners = qw(for on at to with);
+my @joiners = qw(for on at to with of);
 # StartEndTriggers to trigger on nonStrippedTriggers, startTriggers, beautifierTriggers and triggers
 my @triggersStartEnd = (@triggers, @nonStrippedTriggers, @startTriggers, @beautifierTriggers);
 # Ambigous triggers which should not give Timer IA
@@ -117,6 +117,13 @@ handle remainder => sub {
     if($raw =~ /^($ambTrgx)$/){
         return;
     }
+    
+    # When query doesn't ask for timer explicitly and just wants time
+    # calculations, don't invoke IA.
+    if($raw !~ /($trgx)/ and $raw =~ /[+-]/) {
+        return;
+    }
+    
     # When the query is empty and we know that the trigger word matches
     # the trigger exactly (whitespace check) we can return a valid result
     if($qry eq '') {
diff --git a/t/Timer.t b/t/Timer.t
index 7b4f0d5c1..9a927f570 100644
--- a/t/Timer.t
+++ b/t/Timer.t
@@ -104,6 +104,8 @@ ddg_goodie_test(
     'timer 60 minutes'                               => build_test('3600'),
     'start a timer for 20 minutes'                   => build_test('1200'),
     'set a timer to 60 minutes'                      => build_test('3600'),
+    'set a timer of 60 minutes'                      => build_test('3600'),
+    'timer of 5:15 mins'                             => build_test('315'),          
     # Should not trigger
     'start 30 minutes for timer' => undef,
     'run with timer'             => undef,
@@ -121,7 +123,9 @@ ddg_goodie_test(
     '20 minutes'                 => undef,
     ' 22 minutes'                 => undef,
     '60 minutes'                 => undef,
-    '48 hours  '                   => undef
+    '48 hours  '                   => undef,
+    '5:15 + 32 minutes'          => undef,
+    '3:32 - 8 mins'              => undef
 );
 
 done_testing;