Subnet Calculator (IPv4 CIDR)
Calculate IPv4 subnets from any IP and CIDR prefix. Get network address, broadcast, subnet mask, usable host range, and total hosts instantly.
IPv4 address and CIDR
Quick CIDR presets
Network address
192.168.1.0
Class C . 254 usable hosts
Broadcast address
192.168.1.255
Subnet mask
255.255.255.0
Wildcard mask
0.0.0.255
IP class
C
First usable host
192.168.1.1
Last usable host
192.168.1.254
Total addresses
256
Usable hosts
254
Binary mask
11111111.11111111.11111111.00000000
Frequently Asked Questions about the Subnet Calculator (IPv4 CIDR)
What is a subnet mask and CIDR notation?
A subnet mask splits an IP address into network and host parts. CIDR notation writes it as a slash plus the number of network bits: /24 equals 255.255.255.0 and gives you 256 addresses per subnet.
What is the most common subnet for a home network?
/24 (255.255.255.0). It provides 254 usable host addresses, which is more than enough for any home or small office. Routers default to ranges like 192.168.1.0/24 or 192.168.0.0/24.
Why are 2 addresses subtracted from the total?
Every subnet reserves the first address for the network identifier and the last for broadcast. A /24 has 256 total addresses but only 254 are usable for devices.
What is the difference between IP class and CIDR?
Class A, B, and C were the original fixed-size blocks (/8, /16, /24). CIDR replaced them in 1993 and lets you pick any prefix length from /0 to /32, which uses address space far more efficiently.
What are /31 and /32 subnets used for?
A /32 represents a single host, common in routing tables and firewall rules. A /31 (RFC 3021) is used for point-to-point links between two routers where no network or broadcast address is needed.