Networking
Subnet Calculator
Type an IPv4 address plus CIDR prefix to instantly see the network and broadcast addresses, usable host range, wildcard mask, and classful designation.
Break down IPv4 network, broadcast, host counts, and masks from CIDR notation.
Binary mask
11111111.11111111.11111111.00000000
CIDR fundamentals
Network = IP AND subnet mask. Broadcast = network OR wildcard. Usable hosts = 2^(32 − CIDR) − 2 (except /31 and /32, which are treated specially).
How to use
- Enter an IPv4 address such as 192.168.1.42 and set the CIDR prefix (0–32).
- Review the derived subnet mask, wildcard mask, network, and broadcast addresses.
- Copy the usable host range and capacity to plan VLANs, lab exercises, or certification homework.
Example
Input: IP = 192.168.1.42/26
Output: Network = 192.168.1.0, Broadcast = 192.168.1.63, Usable hosts = 62 (192.168.1.1–192.168.1.62)
Student-friendly breakdown
This walkthrough emphasizes the most searched ideas for Subnet Calculator: subnet calculator, cidr calculator, ipv4 subnet calculator, network mask calculator. Start with the formula above, then follow the guided steps to double-check your work. For quick revision, highlight the givens, plug into the equation, and finish by verifying your units.
Need more support? Use the links below to open the long-form guide, browse additional examples, or hop into adjacent calculators within the same topic — each one is a quick way to double-check your work or handle a related question without starting from scratch.
Deep dive & study plan
Subnet Calculator: Breaks down IPv4 networks into mask, host range, broadcast, and host counts. It's built around subnet calculator, cidr, ipv4, so you can go from a raw question to a checked answer without switching tools.
The math behind it: Network = IP AND subnet mask. Broadcast = network OR wildcard. Usable hosts = 2^(32 − CIDR) − 2 (except /31 and /32, which are treated specially).
To use it well: (1) Enter an IPv4 address such as 192.168.1.42 and set the CIDR prefix (0–32). (2) Review the derived subnet mask, wildcard mask, network, and broadcast addresses. (3) Copy the usable host range and capacity to plan VLANs, lab exercises, or certification homework. Keep your units consistent as you go, and re-run a case you already know the answer to — it's the fastest way to catch a typo before it throws off a result you're relying on.
Worked example: entering IP = 192.168.1.42/26 returns Network = 192.168.1.0, Broadcast = 192.168.1.63, Usable hosts = 62 (192.168.1.1–192.168.1.62). Try swapping in your own numbers next, especially a case you're unsure about, before you use this for something that matters.
Quick retention checklist
- Speak the formula aloud (or annotate it) so the relationships stick.
- Write each step in your own words and compare with the numbered list above.
- Swap in new numbers for the Example to make sure the calculator (and your logic) handles edge cases.
- Check at least one related calculator below — it's the fastest way to confirm your numbers still line up from a different angle.
FAQ & notes
Does it support /31 or /32 links?
Yes. /31 shows the two point-to-point addresses as usable, while /32 reserves the single host without a broadcast address.
What about IPv6?
This tool focuses on IPv4 subnetting today. IPv6 planning is on the roadmap as a separate calculator.
What formula does the Subnet Calculator use?
Network = IP AND subnet mask. Broadcast = network OR wildcard. Usable hosts = 2^(32 − CIDR) − 2 (except /31 and /32, which are treated specially).
How do I use the Subnet Calculator?
Enter an IPv4 address such as 192.168.1.42 and set the CIDR prefix (0–32). Review the derived subnet mask, wildcard mask, network, and broadcast addresses. Copy the usable host range and capacity to plan VLANs, lab exercises, or certification homework.