IP Subnet Calculator (IPv4 CIDR)
Enter an IPv4 CIDR like 192.168.1.10/24 and instantly get the network, broadcast, host range, subnet mask, wildcard mask, host counts and address class/type — runs 100% in your browser, no upload.
192.168.1.0192.168.1.255192.168.1.1192.168.1.254255.255.255.00.0.0.255256254CPrivate (RFC 1918)🔒 Calculated in your browser — nothing is uploaded.
What this subnet calculator does
Type an IPv4 address with a CIDR prefix, for example 192.168.1.10/24, and the calculator instantly derives the whole subnet. It shows the network address, broadcast address, the first and last usable host, the subnet mask, the wildcard mask (handy for router ACLs), the total number of addresses and the number of usable hosts. It also identifies the address's classful class (A–E) and its type — whether it is private (RFC 1918), public, loopback, link-local/APIPA, shared/CGNAT, multicast, documentation or reserved. Any host inside the block gives the same result because the host bits are masked off, so 192.168.1.10/24 and 192.168.1.200/24 both resolve to the 192.168.1.0/24 network.
How the numbers are worked out
Everything is pure 32-bit integer math. The prefix length becomes a subnet mask, the mask is ANDed with the address to find the network, and the wildcard (the bit-inverse of the mask) is ORed in to find the broadcast. The total address count is 2^(32 − prefix), and usable hosts are normally the total minus the network and broadcast addresses. Two special cases follow common practice: a /31 is treated as an RFC 3021 point-to-point link where both addresses are usable, and a /32 is a single host.
Frequently asked questions
Is this address private or public?
The tool labels the address type for you. Private ranges (RFC 1918) are 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 — used inside home and office networks and not routable on the public internet. It also flags loopback (127.x), link-local/APIPA (169.254.x, which usually means DHCP failed), shared/CGNAT (100.64.0.0/10), multicast, documentation (TEST-NET) and reserved addresses; anything else is public.
Why do 192.168.1.10/24 and 192.168.1.0/24 give the same result?
The /24 prefix keeps only the first 24 bits (the network part) and masks off the last 8 bits (the host part). Any host address inside the block therefore collapses to the same network, 192.168.1.0, with the same broadcast and host range.
How are usable hosts counted for /31 and /32?
For most prefixes usable hosts equal the total addresses minus the network and broadcast. A /32 is a single host, and a /31 follows RFC 3021 for point-to-point links, where both of its two addresses are treated as usable.
Is my IP address uploaded anywhere?
No. All parsing and subnet math runs locally in your browser with JavaScript. The address you type is never sent, stored or uploaded to any server.