Calculate subnet masks, network addresses, broadcast addresses, and host ranges for IPv4 and IPv6 CIDR blocks.
A CIDR block becomes a set of concrete IPv4 or IPv6 boundaries: its network address, mask or prefix length, final address, and the IPv4 broadcast and host interval where applicable. Entering a host address with a prefix is valid; the calculator clears the host bits to find the containing subnet. The common surprise is that 192.168.1.10/24 falls within 192.168.1.0/24, rather than defining a network beginning at .10. IPv6 results differ because IPv6 has no broadcast address.
A concrete input and expected output from the current implementation.
Input
192.168.1.10/24
Expected output
Network address: 192.168.1.0 Subnet mask: 255.255.255.0 Broadcast address: 192.168.1.255 Host range: 192.168.1.1 - 192.168.1.254
A /24 fixes the first 24 bits and leaves 8 host bits. Setting those 8 bits to zero gives .0, setting them to one gives .255, and the conventional usable IPv4 host range lies between those addresses.
CIDR combines an address with a slash prefix. For IPv4, the prefix is 0 through 32; for IPv6, it is 0 through 128. The network address has every bit after that prefix set to zero. The final address has those bits set to one. An IPv4 subnet mask expresses the same prefix as four decimal octets.
For an ordinary IPv4 subnet, the all-zero host value is the network address and the all-one host value is the directed broadcast address; the conventional host interval lies between them. IPv6 has no broadcast address, so its upper boundary is only the last numeric address in the prefix. These results describe address space, not actual routing or assignment.
Yes. When an interface address includes a prefix length, the containing network is found by clearing its host bits. Both 192.168.1.10/24 and 192.168.1.0/24 therefore produce the network boundary 192.168.1.0/24. The original .10 value can still represent a particular interface address inside that subnet.
No broadcast address exists in IPv6. The calculator can identify the numeric boundaries and size of an IPv6 prefix, but the upper boundary is not a broadcast destination. A mathematical address count also does not establish how many addresses may be assigned, because deployment rules, reserved meanings, and local address plans still apply.
The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
Generate strong, random passwords with customizable length, character sets, and complexity requirements.
Analyze password strength with entropy scoring, crack-time estimates, and improvement suggestions.
Create cryptographically random strings for API keys, tokens, salts, and unique identifiers.
Create QR codes for URLs, text, Wi-Fi credentials, vCards, and more with customizable size and colors.
Scan and decode QR codes from uploaded images or your device camera to extract embedded data.
Compute MD5, SHA-1, SHA-256, and SHA-512 checksums to verify file integrity and detect tampering.