IT Calculator

IP subnetting, RAID sizing, and storage/RAM math

IPv4 Subnet Calculator

Common Public DNS Resolvers (IPv4)

Cloudflare1.1.1.11.0.0.1
Quad99.9.9.9149.112.112.112
Google8.8.8.88.8.4.4
OpenDNS208.67.222.222208.67.220.220

IPv6 Subnet Calculator

Common Public DNS Resolvers (IPv6)

Cloudflare2606:4700:4700::11112606:4700:4700::1001
Quad92620:fe::fe2620:fe::9
Google2001:4860:4860::88882001:4860:4860::8844
OpenDNS2620:119:35::352620:119:53::53

RAID / JBOD Calculator

Storage / RAM

Everything here updates as you type.

Convert a size

Binary (1024) - what Windows, Linux & RAM use

Decimal (1000) - what drive labels & macOS use

Why does a "4 TB" drive show up as 3.64 TB? The box uses decimal units, but Windows counts in binary (TiB) while still labeling it "TB". RAM is always binary: a "16 GB" stick is 16 GiB.

Add it up

Total up a server's RAM or a set of drives. Each line is quantity × size.

Compare two sizes

How much space is left, what percent is used, or how many items fit.