diff --git a/modules/nf-core/star/genomegenerate/main.nf b/modules/nf-core/star/genomegenerate/main.nf
index 744e3ea71d00..a5874d3b1e9b 100644
--- a/modules/nf-core/star/genomegenerate/main.nf
+++ b/modules/nf-core/star/genomegenerate/main.nf
@@ -40,7 +40,7 @@ process STAR_GENOMEGENERATE {
     } else {
         """
         samtools faidx $fasta
-        NUM_BASES=`gawk '{sum = sum + \$2}END{if ((log(sum)/log(2))/2 - 1 > 14) {printf "%.0f", 14} else {printf "%.0f", (log(sum)/log(2))/2 - 1}}' ${fasta}.fai`
+        NUM_BASES=`gawk '{sum = sum + \$2}END{if ((log(sum)/log(2))/2 - 1 > 14) {printf "%.0f", 14} else {printf "%d", int((log(sum)/log(2))/2 - 1)}}' ${fasta}.fai`
 
         mkdir star
         STAR \\