The topic about hardware/software requirements states
~52MB of free space
I'm on the FTLDNS branch and I don't think this specification is not correct anymore.
du -sh /etc/pihole/ => 37M
du -sh /etc/.pihole/ => 7.4M
du -sh /var/www/html/ => 34M
plus
- PHP
- lighttpd
- sqlite3
- dhcpcd
- (dnsmasq)
- git
- many different tools and dependencies