IP / CIDR calculator — network & host count
Crunch an IPv4 CIDR like `192.168.1.10/24` into network address, broadcast, subnet mask, wildcard mask, first/last host, and total host count. Flags private, loopback, and reserved ranges. Everything runs in your browser — perfect for vetting internal network plans without sending them anywhere.
How to use
Enter an IPv4 address in CIDR notation (e.g., `192.168.1.10/24`) to compute the network address, broadcast, subnet mask, wildcard mask, first/last host IP, usable host count, total addresses, and a classification (RFC 1918 private ranges, loopback, link-local, multicast, etc.). If you omit the prefix, the address is treated as `/32`. Use the sample chips for common ranges.
FAQ
- Is the IP uploaded?
- No. Everything is calculated by JavaScript inside your browser, so even internal network plans stay private.
- Is IPv6 supported?
- Currently only IPv4. IPv6 has a 128-bit address space that needs a BigInt-based implementation — it may ship as a separate tool if there is demand.
- What's the difference between usable hosts and total addresses?
- Total is the size of the CIDR range (256 for /24). Usable hosts excludes the network and broadcast addresses (254 for /24). /31 is a special case for point-to-point links where both addresses are usable (2), and /32 is a single-host designation (1).
- Can I enter a host IP with a prefix?
- Yes. A host-like input such as `192.168.1.10/24` is fine — the tool computes the network address (192.168.1.0) and proceeds.
- Is the prefix optional?
- Yes. A bare IP like `8.8.8.8` is treated as `/32` (single host).
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