IP Subnet Calculator
Calculate network address, broadcast, and host range from IPv4 CIDR.
About this tool
Calculate network address, broadcast, and host range from IPv4 CIDR. Turn opaque strings from network traces, devtools, or SEO audits into structured output you can act on.
Enter an IPv4 address and CIDR prefix length (for example 192.168.1.10/24). Read network address, mask, broadcast, and usable host range. Example — Class C-style /24: try `192.168.1.10 / 24` and expect something like `Network address: 192.168.1.0/24 Subnet mask: 255.255.255.0 Broadcast: 192.168.1.255 Usable hosts: 254`.
IPv4 only — IPv6 prefixes are not calculated here. See also: HTTP Header Parser, and CORS Header Generator. Runs in your browser — nothing you paste gets uploaded.
How to use
- Enter an IPv4 address and CIDR prefix length (for example 192.168.1.10/24).
- Read network address, mask, broadcast, and usable host range.
- Use the host counts when sizing VPCs, VPN pools, or lab networks.
- Recalculate when splitting a larger block into smaller subnets.
Example
Class C-style /24
Input
192.168.1.10 / 24
Output
Network address: 192.168.1.0/24 Subnet mask: 255.255.255.0 Broadcast: 192.168.1.255 Usable hosts: 254
Limitations
- IPv4 only — IPv6 prefixes are not calculated here.
- Does not query WHOIS, BGP, or live routing tables.
- /31 and /32 point-to-point cases follow common host-count conventions that some vendors document differently.
Related guides
1Related tools
2Frequently asked questions
What does the IP Subnet Calculator do?
Calculate network address, broadcast, and host range from IPv4 CIDR. Runs in your browser — no install, no account.
How do I use the IP Subnet Calculator?
Enter an IPv4 address and CIDR prefix length (for example 192.168.1.10/24). Read network address, mask, broadcast, and usable host range. Use the host counts when sizing VPCs, VPN pools, or lab networks. Recalculate when splitting a larger block into smaller subnets.
Is the IP Subnet Calculator free?
Yes. No signup, no usage limits, no paywall.
Does the IP Subnet Calculator upload my data?
No. Processing happens locally in JavaScript. Your input is not uploaded, stored, or logged.
What are the limitations of the IP Subnet Calculator?
IPv4 only — IPv6 prefixes are not calculated here. Does not query WHOIS, BGP, or live routing tables. /31 and /32 point-to-point cases follow common host-count conventions that some vendors document differently.