CIDR Calculator
Enter 192.168.1.0/24 or an IP with a mask to see the network, broadcast, host range, usable hosts, netmask, wildcard, binary form and address type. IPv6 too.
How to use the CIDR calculator
- Enter an address with a prefix length (192.168.1.10/24), an IP with a mask (192.168.1.10 255.255.255.0) or an IPv6 address.
- The network details appear right away: network address, broadcast, first and last host, host count, netmask and wildcard.
- To turn an IP range into CIDR blocks, choose "IP range → CIDR" and enter the first and last IP.
Frequently asked questions
In IPv4 the first address is the network address and the last is the broadcast, so neither can be given to a device. A /24 has 256 addresses but 254 hosts. A /31 (a two-point link) and a /32 use every address.
A wildcard is the inverted netmask (0.0.0.255 for a /24), mostly seen in Cisco router ACL and OSPF configuration.
Choose "IP range → CIDR" and enter the first and last IP. You get the fewest CIDR blocks that cover exactly that range, ready for a firewall or an IP block list.
No. IPv6 has no broadcast, and networks are written only with a prefix length such as /64. The tool shows the first and last address, the address count and the fully written form.
Whether the IP is private (used inside a local network, like 192.168.x.x), public, loopback (127.0.0.1), link-local, multicast or reserved for documentation, so you know whether it can reach the Internet.
It is completely free and needs no sign-up.
Related tools
Subnet CalculatorSplit an IPv4 network into subnets, VLSM tooMIME Type LookupLook up MIME types and check a file's real typeURL parserSplit a link into parts and edit its queryUser-Agent parserFind browser, OS and device from a user agentHash generatorGenerate MD5, SHA-1, SHA-256, SHA-384, SHA-512 hashesHMAC GeneratorCreate and verify HMAC signaturesRSA EncryptionGenerate RSA keys, encrypt and decrypt short textPassword GeneratorCreate strong random passwordsPassword strength checkerCheck if a password is weak or strong, and why