IP Keisan combines interactive IP and subnet calculators with public/private address checks, range tools, IPv4/IPv6 references, and practical network setup guides.
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What is this tool?
Calculate IPv4 and IPv6 networks, subnet masks, CIDR ranges, usable hosts, network addresses, and broadcast addresses in a Japanese browser toolkit.
Best for
Network administrators, developers, IT learners, and Japanese-speaking users who need quick subnet and IP reference calculations.
Pricing note
All calculators are free in the browser. Verify production network changes against your organization’s addressing plan and device documentation.
Key features
Use cases
Plan a subnet before configuring a router, server, or lab network.
Check whether an address is public, private, or reserved for a special purpose.
Convert prefix lengths and masks or confirm usable addresses in a CIDR block.
Pros
Cons
How to use
Open the IP Keisan calculator.
Enter an IPv4 or IPv6 address and choose the subnet mask or prefix length.
Run the calculation and review the network, range, broadcast, and host results.
Check the reference guides before applying values to a live network.
FAQ
What can IP Keisan calculate?
It calculates subnet masks, CIDR blocks, network and broadcast addresses, usable ranges, host counts, and selected IPv6 values.
Can it identify private IP addresses?
Yes. The site includes address-type guidance and covers the 10/8, 172.16/12, and 192.168/16 private ranges.
Is IP Keisan free?
Yes. Its browser calculators and network guides are available without payment or registration.
Is the site available in English?
The current interface and most guides are in Japanese, while standard IP, CIDR, IPv4, and IPv6 notation remains recognizable.
