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Key Features
Instant Calculation
Get accurate results in real time with our optimized algorithm.
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Working out a subnet's network address, broadcast address, and usable host range by hand means converting between binary and decimal — tedious and easy to get wrong under time pressure.
This calculator takes any IPv4 address in CIDR notation (like 192.168.1.0/24) and instantly computes the network address, broadcast address, subnet mask, and the full range of usable host addresses.
How it works
Enter an IPv4 address with a CIDR prefix (e.g. 192.168.1.0/24). The tool calculates the subnet mask from the prefix, then derives the network address, broadcast address, and usable host range using standard bitwise subnetting math.
- Enter iPv4 CIDR address.
- Click Calculate to see your results.
Examples
A standard /24 subnet
192.168.1.0/24 has a network address of 192.168.1.0, broadcast address of 192.168.1.255, and 254 usable host addresses (192.168.1.1 through 192.168.1.254).
Who should use it
- Planning IP address allocation for a network segment.
- Verifying subnet boundaries during network troubleshooting.
Industry applications
- Network engineering and administration
- IT infrastructure and DevOps
Advantages
- Handles the /31 and /32 special cases correctly, not just the general subnetting formula.
- Instant calculation without manual binary conversion.
Limitations
- IPv4 only — does not support IPv6 subnetting.
Common mistakes to avoid
- Forgetting that the first and last addresses in a subnet are reserved (network and broadcast) for all prefixes except /31 and /32.
- Confusing the subnet mask with the wildcard mask, which are bitwise inverses of each other.
Best practices
- Double-check whether you're working with a /31 (point-to-point) or /32 (single host) subnet, since both are special cases with different usable-host rules than the general case.
Tips
- When designing a new network, plan subnet sizes based on actual host count needs plus reasonable growth room — oversized subnets waste address space, undersized ones require renumbering later.