diff --git a/check_vcf_samples.wdl b/check_vcf_samples.wdl
index 485714e..243e7e7 100644
--- a/check_vcf_samples.wdl
+++ b/check_vcf_samples.wdl
@@ -9,7 +9,7 @@ workflow check_vcf_samples {
         String workspace_namespace
     }
 
-    Int disk_gb = ceil(size(vcf_file, "GB")*1.5)
+    Int disk_gb = ceil(size(vcf_file, "GB")*1.5) + 5
 
     call vcf_samples {
         input: vcf_file = vcf_file,