diff --git a/tasks/task_consensus_call.wdl b/tasks/task_consensus_call.wdl
index b7cff278..ed8daebc 100644
--- a/tasks/task_consensus_call.wdl
+++ b/tasks/task_consensus_call.wdl
@@ -160,7 +160,7 @@ task consensus {
     echo $num_ACTG | tee NUM_ACTG
 
     # calculate percent coverage (Wu Han-1 genome length: 29903bp)
-    python -c "print ( round( ($num_ACTG / 29903 ) * 100, 2 ) )" | tee PERCENT_REF_COVERAGE
+    python3 -c "print ( round( ($num_ACTG / 29903 ) * 100, 2 ) )" | tee PERCENT_REF_COVERAGE
 
     num_degenerate=$( grep -v ">" ${samplename}.consensus.fa | grep -o -E "B|D|E|F|H|I|J|K|L|M|O|P|Q|R|S|U|V|W|X|Y|Z" | wc -l )
     if [ -z "$num_degenerate" ] ; then num_degenerate="0" ; fi