IPv4 Subnet Calculator
Calculate the network address, broadcast address, usable host range, and subnet mask for any IPv4 address and CIDR.
Network Address
192.168.1.0
Broadcast Address
192.168.1.255
Subnet Mask
255.255.255.0
Wildcard Mask
0.0.0.255
First Usable Host
192.168.1.1
Last Usable Host
192.168.1.254
Usable Hosts
254
Total Addresses
256
CIDR Notation
192.168.1.0/24
Recommended Settings
Pro Tips
- •The CIDR number represents how many bits of the address are fixed for the network portion - a smaller number means a larger subnet with more hosts
- •/31 and /32 are special cases used for point-to-point links and single-host routes, where the usual network/broadcast address split doesn't apply
- •The wildcard mask is simply the inverse of the subnet mask, commonly used in Cisco access control list configurations
- •The network and broadcast addresses themselves aren't usable by hosts - that's why usable host count is normally two less than the total address count
Most Popular
Most people calculate a /24 subnet, the most common home and small-office network size, offering 254 usable addresses
When to Use This Tool
Figure out the full address range and usable hosts for a planned subnet.
Check whether a specific IP address falls within a given subnet's range.
See exactly how a CIDR prefix translates into a subnet mask and address range.
Get the precise network address and mask needed for a routing or firewall rule.
How It Works
Convert the IPv4 address into a single 32-bit integer
Derive the subnet mask from the CIDR prefix length, then compute the network address by masking the IP
Calculate the broadcast address, usable host range, and total address count from the network address and mask
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Client-side 32-bit IPv4 arithmetic for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
What does /24 mean?
It means the first 24 bits of the 32-bit address are fixed as the network portion, leaving 8 bits (256 addresses, 254 usable) for hosts - the standard size for many home and small office networks.
Why are the network and broadcast addresses not usable by hosts?
The network address identifies the subnet itself, and the broadcast address is used to send data to every host on the subnet - neither can be assigned to an individual device.
What's special about /31 and /32?
/32 identifies a single host with no room for a network at all, and /31 is a special case (defined in RFC 3021) used for point-to-point links where both addresses are usable, since there's no room for a separate broadcast address.
Is my IP address sent anywhere?
No. All calculation happens locally in your browser.