IPv4 Subnet Calculator
Parses a CIDR network and works out the full set of details: usable hosts, first and last address, mask and more.
Paste a CIDR like 192.168.1.0/24 and get the full subnet breakdown — usable hosts, first/last address, netmask, wildcard. Built for VPC and VLAN planning, free in your browser.
Steps and notes
What is IPv4 Subnet Calculator?
Paste a CIDR block like 192.168.1.0/24 and get everything a subnet plan needs: network and broadcast addresses, first and last usable host, usable host count, netmask and wildcard mask. Handy for VLAN planning, DHCP scope sizing or double-checking an assignment before you apply it.
- Enter the CIDR (e.g. 192.168.1.0/24)
- Read the results below
- Copy whichever field you need
- The network address and broadcast address normally cannot be assigned to a host
Frequently asked questions
- How many addresses are in a /24?
- 256 total. Subtracting the network and broadcast addresses leaves 254 usable hosts — this is the most common home-lab and small-office subnet.
- Why do two addresses disappear from the usable count?
- The lowest address identifies the network itself and the highest is reserved for broadcast, so neither can be assigned to a host. The calculator shows them explicitly so nothing surprises you.
- What is a wildcard mask for?
- It is the inverted netmask (0.0.0.255 for /24). Access control lists on routers and some firewalls are written with wildcards instead of netmasks, and mixing the two up breaks matching.
- How do I calculate a subnet mask from CIDR?
- Paste the CIDR (192.168.1.0/24) and the netmask, wildcard, host range and usable count are all derived at once — no manual binary math. /24 → 255.255.255.0, /26 → 255.255.255.192, and so on.
Category: Network
Network & IP workflow
IPv4 Subnet Calculator → IPv4 range expander → IPv4 address converter → IPv6 ULA generator → MAC address generator → MAC address lookup → WHOIS lookup