diff --git a/docker/docker_tar_to_chroot.sh b/docker/docker_tar_to_chroot.sh
index 6ba4080..705bc81 100755
--- a/docker/docker_tar_to_chroot.sh
+++ b/docker/docker_tar_to_chroot.sh
@@ -2,24 +2,25 @@
 # This script takes a Docker container export (.tar) creates a chroot image (.img)
 # Note that root privileges are required to mount the loopback images 
 
-# Syntax: ./docker_tar_to_chroot.sh docker-export.tar chroot.img
+# Syntax: ./docker_tar_to_chroot.sh docker-export.tar chroot.img optional_buffer_size_in_mb
 
 EXPORT_FILE=${1}
 CHROOT_FILE=${2}
+BUFFER_MB=${3:-50}
 
 # Files have a minimum storage size of 4k due to block size
 exportSize=$(tar -tvf "${EXPORT_FILE}" | awk '{s+=int($3/4096+0.99999)*4096} END{printf "%.0f\n", s}')
 
 # Add a minimum buffer of free space to account for filesystem overhead
-chrootMinSize=$(( exportSize/(1024*1024) * 115/100 + 50))
+chrootMinSize=$(( exportSize/(1024*1024) * 115/100 + ${BUFFER_MB}))
 
 # Round up to the nearest 100 MB
 chrootSize=$(( ((${chrootMinSize%.*})/100+1)*100 ))
 
-echo ------------------------------------------------------------
-echo Total size of files from Docker image is $(( exportSize/(1024*1024) )) MB
-echo Creating chroot file ${CHROOT_FILE} of size $chrootSize MB
-echo ------------------------------------------------------------
+echo ----------------------------------------------------------------------
+echo Total size of files from Docker image is $(( exportSize/(1024*1024) )) MB with ${BUFFER_MB} MB of buffer
+echo Creating chroot file ${CHROOT_FILE} of size ${chrootSize} MB
+echo ----------------------------------------------------------------------
 
 if test -f "${CHROOT_FILE}"; then
     echo "Warning -- ${CHROOT_FILE} exists and will be overwritten!"
diff --git a/docker/docker_to_chroot.bat b/docker/docker_to_chroot.bat
index 2af99a9..6d1cde0 100755
--- a/docker/docker_to_chroot.bat
+++ b/docker/docker_to_chroot.bat
@@ -1,16 +1,23 @@
 @echo off
+setlocal enabledelayedexpansion
+
 rem This script takes a Docker image and creates a chroot image (.img)
 rem Note that this script also requires docker_tar_to_chroot.sh to be located in the same folder
  
-rem Syntax: docker_to_chroot.bat kspacekelvin/fire-python fire-python-chroot.img
+rem Syntax: docker_to_chroot.bat kspacekelvin/fire-python fire-python-chroot.img optional_buffer_size_in_mb
  
 if     "%1"=="" GOTO wrongargnum
 if     "%2"=="" GOTO wrongargnum
-if not "%3"=="" GOTO wrongargnum
  
 set DOCKER_NAME=%1
 set CHROOT_FILE=%2
 set EXPORT_FILE=docker-export.tar
+
+if "%3"=="" (
+  set BUFFER_SIZE=50
+) else (
+  set BUFFER_SIZE=%3
+)
  
 if exist %EXPORT_FILE% (
   echo Warning -- %EXPORT_FILE% exists and will be overwritten!
@@ -31,12 +38,12 @@ docker run -it --rm          ^
            --privileged=true ^
            -v "%cd%":/share  ^
            ubuntu            ^
-           /bin/bash -c "sed -i -e 's/\r//g' /share/docker_tar_to_chroot.sh && /share/docker_tar_to_chroot.sh /share/%EXPORT_FILE% /share/%CHROOT_FILE%"
+           /bin/bash -c "sed -i -e 's/\r//g' /share/docker_tar_to_chroot.sh && /share/docker_tar_to_chroot.sh /share/%EXPORT_FILE% /share/%CHROOT_FILE% !BUFFER_SIZE!"
  
 del %EXPORT_FILE%
 goto eof
  
 :wrongargnum
-echo Syntax: docker_to_chroot.bat docker_image_name chroot_file_name
+echo Syntax: docker_to_chroot.bat docker_image_name chroot_file_name optional_buffer_size_in_mb
  
 :eof
diff --git a/docker/docker_to_chroot.sh b/docker/docker_to_chroot.sh
index 49391fb..d17ae73 100755
--- a/docker/docker_to_chroot.sh
+++ b/docker/docker_to_chroot.sh
@@ -1,17 +1,18 @@
 #!/bin/bash
 # This script takes a Docker image and creates a chroot image (.img)
 
-# Syntax: ./docker_to_chroot.sh docker_image_name chroot_file_name
+# Syntax: ./docker_to_chroot.sh docker_image_name chroot_file_name optional_buffer_size_in_mb
 
-if [[ $# -ne 2 ]]; then
+if [[ $# -gt 3 ]]; then
     echo "Wrong number of arguments" >&2
-    echo "Syntax: ./docker_to_chroot.sh docker_image_name chroot_file_name" >&2
+    echo "Syntax: ./docker_to_chroot.sh docker_image_name chroot_file_name optional_buffer_size_in_mb" >&2
     exit 2
 fi
 
 DOCKER_NAME=${1}
 CHROOT_FILE=${2}
 EXPORT_FILE=docker-export.tar
+BUFFER_MB=${3:-50}
 
 # Create a Docker container and export to a .tar file
 echo ------------------------------------------------------------
@@ -32,6 +33,6 @@ docker run -it --rm          \
            --privileged=true \
            -v $(pwd):/share  \
            ubuntu            \
-           /bin/bash -c "sed -i -e 's/\r//g' /share/docker_tar_to_chroot.sh && /share/docker_tar_to_chroot.sh /share/${EXPORT_FILE} /share/${CHROOT_FILE}"
+           /bin/bash -c "sed -i -e 's/\r//g' /share/docker_tar_to_chroot.sh && /share/docker_tar_to_chroot.sh /share/${EXPORT_FILE} /share/${CHROOT_FILE} ${BUFFER_MB}"
 
 rm ${EXPORT_FILE}