diff --git a/scripts/db-backup.sh b/scripts/db-backup.sh
index e4185ec..27abbf1 100755
--- a/scripts/db-backup.sh
+++ b/scripts/db-backup.sh
@@ -52,9 +52,9 @@ ensure_postgres_running() {
 
 format_size() {
   local bytes=$1
-  if   (( bytes >= 1073741824 )); then printf "%.1f GB" "$(echo "$bytes / 1073741824" | bc -l)"
-  elif (( bytes >= 1048576 ));    then printf "%.1f MB" "$(echo "$bytes / 1048576" | bc -l)"
-  elif (( bytes >= 1024 ));       then printf "%.1f KB" "$(echo "$bytes / 1024" | bc -l)"
+  if   (( bytes >= 1073741824 )); then printf "%d.%d GB" $((bytes / 1073741824)) $(( (bytes % 1073741824) * 10 / 1073741824 ))
+  elif (( bytes >= 1048576 ));    then printf "%d.%d MB" $((bytes / 1048576))    $(( (bytes % 1048576)    * 10 / 1048576 ))
+  elif (( bytes >= 1024 ));       then printf "%d.%d KB" $((bytes / 1024))       $(( (bytes % 1024)       * 10 / 1024 ))
   else printf "%d B" "$bytes"
   fi
 }