IPv4 network toolbox
Calculate IPv4 subnets, masks, host capacity, ranges, conversions, and same-subnet checks locally.
Inputs stay in your browser
Interactive tool
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The IPv4 network toolbox groups subnet calculation, mask conversion, host planning, range-to-CIDR conversion, IPv4 notation conversion, local classification, and same-subnet checks on one canonical page. Each module keeps its own input, validation, result, copy, and reset state.
When to use this tool
- Plan a LAN prefix and usable host capacity before configuring routers or firewalls.
- Convert address ranges, masks, and IPv4 notation without sending network data outside the browser.
How to use
- Start with the subnet module and try 192.168.1.10/24.
- Use the anchor navigation to move to mask, host, range, converter, or same-subnet modules.
- Review each module result independently; correcting one module does not clear or overwrite another module.
Example
Subnet and range planning
192.168.1.10/24 reports the 192.168.1.0 network, 255.255.255.0 mask, 254 usable hosts, and range boundaries.
How it works
- IPv4 addresses are converted to unsigned 32-bit integers. Masks must be contiguous, ranges are summarized exactly, and /31 follows RFC 3021 point-to-point behavior.
Limits and notes
- Classful networking is not used.
- Ambiguous leading-zero IPv4 octets and non-contiguous masks are rejected.
- The page does not contact DNS or any external network service.
Frequently asked questions
Why are several IPv4 functions on one page?
They share the same IPv4 addressing model, so grouping them avoids duplicate pages while keeping each module independent.
Does range-to-CIDR approximate?
No. Returned CIDR blocks do not cover addresses outside the requested IPv4 range.
References
Related tools
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