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Usage tip: Simply enter the IP and prefix to calculate automatically. All data is processed locally and never uploaded to any server.
Enter IP Address & CIDR
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/
Binary Representation
Calculation Results
Subnet Mask
255.255.255.255
Network Address
192.168.1.1
Broadcast Address
192.168.1.1
First Usable IP
192.168.1.1
Last Usable IP
192.168.1.1
Usable IP Count
1
How to calculate a CIDR range
- Enter a network address with its prefix length, for example 192.168.1.0/24.
- Read the network address and broadcast address the block resolves to.
- Check the usable host range and total usable host count.
- Use the binary view to see exactly which bits are network and which are host — invaluable when planning subnets.
Frequently Asked Questions
What is CIDR?
CIDR (Classless Inter-Domain Routing) represents IP address ranges with a /prefix length, e.g., 192.168.1.0/24.
What can it calculate?
It automatically computes the network address, broadcast address, and usable IP range, with binary view and full results.
What does the /24 in an address mean?
It says how many leading bits are the network part. A /24 fixes the first 24 bits, leaving 8 host bits — 256 addresses, of which 254 are usable.
How many usable hosts does a /26 have?
Six host bits give 64 addresses; subtracting the network and broadcast addresses leaves 62 usable hosts. The calculator shows this count for any prefix you enter.
Why is the binary view useful?
Subnetting decisions happen at the bit level. Seeing which bits are fixed and which vary makes it obvious whether two addresses share a network or need a router between them.
Technical References
- CIDR — RFC 4632: https://www.rfc-editor.org/rfc/rfc4632
- RFC 4632 — Classless Inter-domain Routing (CIDR): https://datatracker.ietf.org/doc/html/rfc4632