Network · IP and CIDRCheck and inspect an IP address or CIDR
Check an IP address or a CIDR block: version, type, mask, range and representations in every common format. It all runs in the browser, with no network requests.
Computed locally — the address is never sent anywhere
01
IP / CIDR breakdown
version and format are detected automatically02
About IP and CIDR
An IP address is the number of a device on a network. A CIDR block such as 192.168.1.0/24 describes a whole network rather than one address: the number after the slash says how many bits belong to the network and how many are left for devices. From that alone the mask, the range and the host count follow — no lookups required.
IPv4 and IPv6
Versions192.168.0.1 · ::1
IPv4 is four numbers from 0 to 255. IPv6 is longer and hexadecimal, with runs of zeros collapsed into a double colon.
Private addresses
Type10/8 · 172.16/12 · 192.168/16
Ranges reserved for internal networks; they are not routed on the internet. Next to them sits 100.64/10, carrier NAT, routinely mistaken for public space.
What CIDR is
Network/24 = 256 addresses
The number after the slash says how many bits belong to the network. A /24 leaves 8 bits for hosts, so 256 addresses in total.
Subnet mask
Boundary/24 = 255.255.255.0
The mask separates the network part from the host part. A /N prefix and a dotted mask are the same thing said differently.
Address representations
Formsdotted · int · hex · bin
One address can be written with dots, as an integer, in hex or in binary — each form turns up in code, logs and configs.
Computed locally
Privacyno requests
The breakdown is arithmetic on the number behind the address. No DNS, no lookups: the address never leaves the browser.
03
Frequently asked questions
Updated