diff --git a/scripts/size_compare.sh b/scripts/size_compare.sh
new file mode 100755
index 0000000000..8b047a451e
--- /dev/null
+++ b/scripts/size_compare.sh
@@ -0,0 +1,151 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Copyright (C) 2020 Paul Spooren <mail@aparcar.org>
+#
+###
+### size_compare - compare size of OpenWrt packages against upstream
+###
+### The script compares locally compiled package with the package indexes
+### available upstream. This way the storage impact of optimizations or
+### feature modifiactions is easy to see.
+###
+### If no environmental variables are set the scritp reads the current
+### .config file. The evaluated env variables are the following:
+###
+###   TARGET SUBTARGET ARCH PACKAGES BIN_DIR BASE_URL CHECK_INSTALLED
+###
+### Usage:
+###   ./scripts/size_compare.sh
+###
+### Options:
+###   -p --package-size 	Check IPK package size and not installed size
+###   -h --help 		This message
+
+CONFIG_TARGET=$(sed -n 's/^CONFIG_TARGET_BOARD="\(.*\)"$/\1/p' .config)
+CONFIG_SUBTARGET=$(sed -n 's/^CONFIG_TARGET_SUBTARGET="\(.*\)"$/\1/p' .config)
+CONFIG_ARCH=$(sed -n 's/^CONFIG_TARGET_ARCH_PACKAGES="\(.*\)"$/\1/p' .config)
+CONFIG_PACKAGES=$(sed -n 's/^CONFIG_PACKAGE_\(.*\)=y$/\1/p' .config | tr '\n' ' ')
+CONFIG_BIN_DIR=$(sed -n 's/^CONFIG_BINARY_DIR="\(.*\)"$/\1/p' .config)
+
+TARGET=${TARGET:-$CONFIG_TARGET}
+SUBTARGET=${SUBTARGET:-$CONFIG_SUBTARGET}
+ARCH=${ARCH:-$CONFIG_ARCH}
+PACKAGES=${PACKAGES:-$CONFIG_PACKAGES}
+BIN_DIR=${CONFIG_BIN_DIR:-./bin}
+BASE_URL="${BASE_URL:-https://downloads.openwrt.org/snapshots}"
+CHECK_INSTALLED="${CHECK_INSTALLED:-y}"
+
+TARGET_URL="$BASE_URL/targets/$TARGET/$SUBTARGET/packages/Packages.gz"
+CONFIG_URL="$BASE_URL/targets/$TARGET/$SUBTARGET/config.buildinfo"
+PACKAGES_URL="$BASE_URL/packages/$ARCH/base/Packages.gz"
+
+if command -v curl > /dev/null; then
+	DOWNLOAD_METHOD="curl"
+else
+	DOWNLOAD_METHOD="wget --output-document=-"
+fi
+
+help() {
+    sed -rn 's/^### ?//;T;p' "$0"
+}
+
+package_size () {
+	FOUND_PACKAGE=
+	if [ -z "$CHECK_INSTALLED" ]; then
+		SEARCH_PATTERN="Size"
+	else
+		SEARCH_PATTERN="Installed-Size"
+	fi
+	while IFS= read -r line; do
+		if [ "$line" = "Package: $2" ]; then
+			FOUND_PACKAGE=y
+		fi
+		if [ -n "$FOUND_PACKAGE" ]; then
+			case $line in
+				"$SEARCH_PATTERN"*)
+					echo "$line" | cut -d ' ' -f 2
+					break
+					;;
+			esac
+		fi
+	done < "$1"
+}
+
+compare_sizes () {
+	for PACKAGE in $PACKAGES; do
+		if [ "$PACKAGE" = "libc" ]; then
+			continue
+		fi
+		PACKAGE_FILE=$(find "$BIN_DIR/packages/$ARCH/" \
+			"$BIN_DIR/targets/$TARGET/$SUBTARGET/" \
+			-name "${PACKAGE}_*.ipk" 2>/dev/null | head -n1)
+
+		if [ -z "$PACKAGE_FILE" ]; then
+			continue
+		fi
+		if [ -z "$CHECK_INSTALLED" ]; then
+			SIZE_LOCAL=$(stat -c '%s' "$PACKAGE_FILE")
+		else
+			SIZE_LOCAL=$(tar tzvf "$PACKAGE_FILE" ./data.tar.gz | awk '{ print $3 }')
+		fi
+		SIZE_UPSTREAM=$(package_size "$TMP_INDEX" "$PACKAGE")
+		SIZE_DIFF="$((SIZE_LOCAL-SIZE_UPSTREAM))"
+		if [ "$SIZE_DIFF" -gt 0 ]; then
+			SIZE_DIFF="+$SIZE_DIFF"
+		fi
+		if [ -n "$SIZE_UPSTREAM" ]; then
+			echo "${SIZE_DIFF}	${SIZE_LOCAL}	${SIZE_UPSTREAM}	$PACKAGE"
+		else
+			echo "$PACKAGE is missing upstream"
+		fi
+	done
+}
+
+if [ "$1" = "-h" ]; then
+    help
+    exit 0
+fi
+
+if [ "$1" = "-p" ]; then
+    CHECK_INSTALLED=
+fi
+
+echo "Compare packages of $TARGET/$SUBTARGET/$ARCH":
+echo "$PACKAGES"
+echo
+
+echo "Checking configuration difference"
+TMP_CONFIG=$(mktemp /tmp/config.XXXXXX)
+sed -n 's/^	\+config \(.*\)/\1/p' config/Config-build.in config/Config-devel.in > "${TMP_CONFIG}-FOCUS"
+sort .config | grep -f "${TMP_CONFIG}-FOCUS" | grep -v "^#" | sort > "${TMP_CONFIG}-LOCAL"
+mv .config .config.bak
+"$DOWNLOAD_METHOD" "$CONFIG_URL" > .config
+make defconfig > /dev/null 2> /dev/null
+grep -f "${TMP_CONFIG}-FOCUS" .config | grep -v "^#" | sort > "${TMP_CONFIG}-UPSTREAM"
+mv .config.bak .config
+
+echo
+echo " --- start config diff ---"
+diff -u "${TMP_CONFIG}-LOCAL" "${TMP_CONFIG}-UPSTREAM"
+echo " --- end config diff ---"
+rm "${TMP_CONFIG}-FOCUS" "${TMP_CONFIG}-UPSTREAM" "${TMP_CONFIG}-LOCAL"
+echo
+
+if [ -z "$CHECK_INSTALLED" ]; then
+	echo "Checking IPK package size"
+else
+	echo "Checking installed size"
+fi
+echo
+
+echo "Fetching latest package indexes..."
+TMP_INDEX=$(mktemp /tmp/size_compare_package_index.XXXXXX)
+"$DOWNLOAD_METHOD" "$TARGET_URL" | gzip -d > "$TMP_INDEX" || exit 1
+"$DOWNLOAD_METHOD" "$PACKAGES_URL" | gzip -d >> "$TMP_INDEX" || exit 1
+echo
+
+echo "Comparing package sizes..."
+echo "Change 	Local	Remote 	Package"
+compare_sizes | sort -g -r
+
+rm "$TMP_INDEX"