CIDR Calculator
Calculate CIDR ranges, subnet masks, host counts
CIDR Calculator is a free online tool from BrowserUtils that calculate cidr ranges, subnet masks, host counts. It runs entirely in your browser — your data never leaves your device. No account required.
Network Address192.168.1.0
Broadcast Address192.168.1.255
Subnet Mask255.255.255.0
Wildcard Mask0.0.0.255
Subnet (Binary)11111111.11111111.11111111.00000000
First Usable Host192.168.1.1
Last Usable Host192.168.1.254
Total Addresses256
Usable Hosts254
CIDR Prefix/24
IP ClassC
How to use CIDR Calculator
- 1 Paste or type your input into the editor above.
- 2 The tool processes your data instantly — right in your browser, with nothing sent to a server.
- 3 Copy the result with one click or continue editing your input.
About CIDR Calculator
Free online CIDR calculator. Calculate network address, broadcast address, subnet mask, wildcard mask, and host count from any CIDR notation. This tool runs entirely in your browser — your data is never sent to a server. Just paste your input, get instant results, and copy with one click. No sign-up or installation required.
CIDR Calculator specs
- Runtime
- 100% client-side (browser)
- Built on
- WHATWG URL API and Headers/Fetch standards as implemented by modern browsers
- Cost
- Free — no account, no rate limits, no usage caps
- Browser support
- Chrome 90+, Firefox 88+, Safari 14+, Edge 90+
- Part of
- 299 developer tools on BrowserUtils (100% client-side)
Questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation represents an IP address and its network prefix length, written as IP/prefix (e.g., 192.168.1.0/24). The prefix length indicates how many bits define the network portion.
How do I calculate the number of hosts in a subnet?
The number of usable hosts is 2^(32 - prefix length) - 2. The subtraction of 2 accounts for the network address and broadcast address. For example, a /24 network has 2^8 - 2 = 254 usable hosts.
What is a subnet mask and how does it relate to CIDR?
A subnet mask is a 32-bit number that separates the network and host portions of an IP address. A /24 CIDR prefix is equivalent to a subnet mask of 255.255.255.0. The CIDR calculator shows both representations.
What is the broadcast address in a subnet?
The broadcast address is the last address in a subnet, used to send packets to all hosts on that network. For example, in 192.168.1.0/24, the broadcast address is 192.168.1.255.
Does the CIDR calculator work offline?
Yes, all subnet calculations are performed locally in your browser using JavaScript. No network requests are made.
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