diff --git a/samtools.wdl b/samtools.wdl
index 4949569359e4b80a398b39c03f461cd26bb98429..5daf57ab3375ddb57193b4ad868268c755ddd079 100644
--- a/samtools.wdl
+++ b/samtools.wdl
@@ -209,7 +209,7 @@ task Flagstat {
         File inputBam
         String outputPath
 
-        String memory = "1G"
+        String memory = "256M"  # Only 40.5 MiB used for 150G bam file.
         Int timeMinutes = 1 + ceil(size(inputBam, "G"))
         String dockerImage = "quay.io/biocontainers/samtools:1.8--h46bd0b3_5"
     }