Network Engineer
IP Subnet Calculator
Use this ip subnet calculator entirely in your browser.
Subnet mask: 255.255.255.0
Broadcast: 192.168.1.255
Usable hosts: 254
Host range: 192.168.1.1 – 192.168.1.254
Calculations happen locally in your browser.
How to use this calculator
- Enter the labelled values and review the live result.
- Review the live result and use Copy result when you need to share it.
How the calculation works
Bitwise CIDR masking identifies network and broadcast addresses locally.
Formula
Bitwise CIDR masking identifies network and broadcast addresses locally.
Step-by-step calculation
- Enter the labelled values and review the live result.
- Bitwise CIDR masking identifies network and broadcast addresses locally.
- Check the displayed result, then copy it if needed.
Worked example
192.168.1.42/24 belongs to network 192.168.1.0/24.
Methodology and review
Who this is for
People inspecting an IPv4 CIDR network.
Inputs and units
- IPv4 address
- CIDR prefix
Method
The IPv4 address and CIDR prefix are converted to 32-bit integers to derive mask, network, broadcast, range, and address count.
Worked example
192.168.1.10/24 belongs to network 192.168.1.0 with broadcast 192.168.1.255.
Assumptions
- Input is valid IPv4 CIDR notation.
- Usable-host conventions are shown separately from total addresses.
Common mistakes
- Using a dotted mask as a prefix
- Assuming /31 follows traditional host subtraction
Limitations
- Point-to-point and provider rules can use address ranges differently.
- The tool does not inspect or change a live network.
How this tool was checked
Tests cover private and public examples, /31 and /32 boundaries, masks, ranges, and invalid octets.
Reference sources
Related tools
Calculation review: 21 August 2026. Published by Goldwave Dynamics Limited. This is an internal product review, not an independent certification.
Risk guidance
Frequently asked questions
Does this tool send my inputs anywhere?
No. The interactive calculation runs in your browser and this site does not submit tool inputs to a backend.
How should I use the result?
Check that the entered units and values match your situation, especially around dates, breaks, and rounding.
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