IPv4 Subnet Calculator Online (CIDR)
Runs 100% in your browser — your files never leave your device.
Slicing networks by hand is where address math goes wrong. Enter an IPv4 address with or without a mask — 192.168.0.1/24, 10.0.0.0/8 — and read the full breakdown: netmask, network address, wildcard mask, first and last usable hosts, broadcast address, block size, and IP class. Step to the previous or next block with one click.
How it works
- 1
Enter an address or CIDR
Both plain addresses and IP/mask notation are parsed.
- 2
Read the breakdown
Netmask, host range, broadcast address, size, and class appear instantly.
- 3
Walk adjacent blocks
Previous/next buttons shift the block by its own size.
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