Calculate a CIDR subnet
Calculate network address, broadcast, host range, subnet mask and host count from CIDR notation, with binary view. Free subnet calculator.
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About CIDR Calculator
Plan networks, VPCs and firewall rules with confidence. Enter an IPv4 address with a CIDR prefix such as 10.0.0.0/16 and instantly see the network and broadcast addresses, the usable host range, the subnet mask, the wildcard mask and the number of hosts, plus a binary breakdown of the address. It is a handy companion when setting up AWS, Azure or Google Cloud networks.
How to use CIDR Calculator
- 1
Enter an IP with a CIDR prefix, for example 192.168.1.0/24.
- 2
Read the network, broadcast and host range.
- 3
Check the subnet mask and host count.
- 4
Use the binary view to understand the split.
Why use this tool
- Network and broadcast addresses.
- First and last usable host.
- Subnet and wildcard masks.
- Total and usable host counts.
- Binary representation.
Frequently asked questions
The first 24 bits are the network part, leaving 256 addresses, of which 254 are usable hosts.
65,536 addresses, with 65,534 usable hosts on a traditional network.
AWS, for example, reserves five addresses in each subnet for routing and DNS, so plan for fewer usable hosts.
This calculator works with IPv4 addresses.
The inverse of the subnet mask, used in some firewall and router access lists.
No. Everything is processed in your browser tab. Nothing you type or paste is sent to CodeMites or any other server.
Yes. There is no account, no watermark and no usage limit. The tool runs in your own browser, so there is no server cost to charge you for.
Yes. It runs in any modern browser on Android and iOS as well as on Windows, macOS and Linux, with nothing to install.
Yes, once the page has loaded. Everything runs in your browser, so you can keep working on a train or plane without a connection.
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