Calculate complete network details for IPv4 and IPv6 addresses in CIDR notation. Network address, broadcast, host range, subnet mask, and binary representation.
Open IP & Subnet Calculator → free, no sign-inNetwork planning requires subnet arithmetic: given an IP address and CIDR notation, what's the network address, broadcast address, usable host range, and number of hosts? For IPv6 it's even more complex. The IP & Subnet Calculator handles both IPv4 and IPv6: enter an address in CIDR notation and get all the critical network details — including binary representations — immediately.
Network engineers planning subnets, system administrators configuring firewall rules or DHCP ranges, DevOps engineers designing VPC network layouts, or students studying networking who need to verify their manual calculations.
No tutorials. No learning curve. Open it and get started.
No server uploads. Shows binary representations alongside decimal — useful for understanding the actual bit-level subnet mask logic.
Completely free. No trial period. No premium tier for basic functionality. No account required. Use it as often as you need.
One job, done well. IP & Subnet Calculator was built to solve a specific problem cleanly. No feature bloat, no ads, no distractions.
What is CIDR notation?
Classless Inter-Domain Routing — an IP address followed by a slash and the number of network bits (e.g. 192.168.1.0/24 means the first 24 bits are the network prefix).
How many hosts can a /24 subnet hold?
A /24 gives 254 usable hosts (256 addresses minus network and broadcast).
What is the broadcast address?
The last address in a subnet — used to send data to all hosts in the network.
Does it support IPv6?
Yes — IPv6 CIDR notation is supported.
What is a private IP range?
10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 are reserved for private networks.
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