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IPv4 subnet calculator

Network, broadcast, mask, wildcard, and host counts for any CIDR — exact BigInt math, RFC 3021 /31 handling included, computed in this tab.
parsed by ip-address 10.5.0 · computed here, never looked upCalculateClear
 Network address 192.0.2.128
 First usable host 192.0.2.129
 Last usable host 192.0.2.190
 Broadcast 192.0.2.191
 Subnet mask 255.255.255.192
 Wildcard mask 0.0.0.63
 Usable hosts 62
 Total addresses 64
 Legacy class CCheck

- ip-address (MIT) decides what parses; the math is the site's own BigInt layer, so a /11 or a /30 computes exactly — no float ever touches an address value.
- Usable hosts means total minus network and broadcast, the classic convention — except /31 (RFC 3021 point-to-point: both addresses usable) and /32 (one host). The convention in force is printed on every result.
- Host bits set in your input are called out, not dropped: 192.0.2.130/26 reports the 192.0.2.128 network and says why.
- The legacy class letter is a historical label — routing has been classless since CIDR (RFC 4632), and the row says so.
Done

Finished here in the tab. Nothing was uploaded.

exact values — the same engine the VLSM planner and splitter use

Next door in Network

- IPv6 prefix calculator (/network/ipv6-subnet)
- Subnet split & aggregate (/network/subnet-split)
All network tools (/network)

Canonical HTML: https://nutter.tools/network/ipv4-subnet
Markdown version: https://nutter.tools/network/ipv4-subnet/index.md
Plain-text version: https://nutter.tools/network/ipv4-subnet/index.txt
Agent index: https://nutter.tools/llms.txt