Network & Commissioning Tool
IP Subnet Calculator
Convert CIDR to mask, find the network, broadcast and usable host range, and lay out IP addresses for the PLCs, HMIs and drives on a line — all in the browser.
| Role | Name | Assigned IP | |
|---|---|---|---|
| 192.168.1.10 | |||
| 192.168.1.11 | |||
| 192.168.1.12 | |||
| 192.168.1.13 | |||
| 192.168.1.14 |
A common convention on a machine line is a private /24 such as 192.168.1.0/24: the gateway or managed switch takes .1, the PLC takes .10, HMIs and drives follow in blocks. Keep each cell or line on its own subnet so PROFINET and EtherNet/IP multicast traffic stays local. Educational tool; confirm addresses against your network plan before commissioning.
Questions
Frequently Asked
How do I convert CIDR to a subnet mask?
The CIDR prefix is the count of leading 1 bits in the mask. A /24 sets the first 24 bits, which is 255.255.255.0. A /26 sets 26 bits, which is 255.255.255.192. Slide the prefix in the calculator and the mask, host range and broadcast all update together, so you never have to do the binary by hand.
What is the usable host range on a /24?
A /24 holds 256 addresses. The first is the network address and the last is the broadcast, so 254 are usable for devices. On 192.168.1.0/24 the usable range is 192.168.1.1 to 192.168.1.254. Most machine lines live comfortably inside a single /24.
How should I assign IPs to PLCs, HMIs and drives?
Pick a private subnet for the line, give the gateway or managed switch a low address like .1, then assign the PLC a memorable address like .10 and group HMIs, drives and remote I/O in blocks after it. The device planner in this tool does exactly that: set a start offset and it lays out sequential addresses you can copy straight into your network plan.
Why keep each cell or line on its own subnet?
PROFINET and EtherNet/IP both lean on multicast and broadcast traffic for discovery and I/O. Keeping each cell on its own subnet, often a /24, contains that traffic so it does not flood the wider plant network and slow other devices. It also makes troubleshooting far easier because each line has a clean, predictable address block.
What are /31 and /32 used for?
A /31 gives two addresses with no network or broadcast reserved, which is the standard for point-to-point links between two devices. A /32 is a single host address, used for loopbacks and host routes. The calculator handles both edge cases correctly instead of reporting zero usable hosts.
Is anything sent to a server?
No. Every calculation runs in your browser. No IP addresses, device names or network details leave your machine.