Quick start
- Enter an IPv4 address such as 192.168.1.10.
- Enter a CIDR prefix length from 0 to 32.
- Calculate to see mask, wildcard, network, broadcast, and usable range.
Best uses
Use this guide when one of these tasks matches what you are trying to do.
- Find the network and broadcast address for an IPv4 CIDR block.
- Convert a prefix length such as /24 into a dotted decimal subnet mask.
- Check usable host range and address count.
- Practice subnetting for networking, security, or developer work.
What the calculator is doing
The calculator converts IPv4 octets to a 32-bit number, builds the CIDR subnet mask, then uses bitwise network and wildcard math.
How to read the answer
After calculating, read the main answer first, then use the supporting metrics to understand the context.
- Network address is the first address in the CIDR block.
- Broadcast address is the last address in normal IPv4 subnet notation.
- Usable range excludes network and broadcast except for /31 and /32 style cases.
Common mistakes to avoid
Most wrong answers come from using the wrong unit, date, weight, scale, or policy assumption.
- Do not use this for IPv6 subnetting.
- Do not assume the calculator changes any live network setting.
- Check your router, cloud provider, or firewall rules before applying subnet plans.
Research and references
These references shaped the calculator assumptions, unit choices, or safety notes.
Examples from the calculator
Network 192.168.1.0, usable 192.168.1.1-192.168.1.254
16 total addresses
2 usable /31 addresses
Common questions
What can I use the Subnet Calculator for?
Use it for quick everyday planning, school work, technical checks, or comparison tasks when the inputs match the tool page.
How does the Subnet Calculator calculate the result?
The calculator converts IPv4 octets to a 32-bit number, builds the CIDR subnet mask, then uses bitwise network and wildcard math.
What should I double-check before using the answer?
This tool covers IPv4 CIDR math. It does not configure routers, validate a live network, or handle IPv6 subnets.
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History, privacy, and copying
Recent answers stay visible in the page while you work. The history is kept only in the current browser tab and is not sent to a server.
Copy answer copies the expression and result so you can paste it into notes, homework, a message, or another document.