Best Free Online Developer Tools to Use in 2026
A practical, opinionated list of the best free online developer tools worth using in 2026, organized by category so you can find what you need fast.
Aug 08, 2026
Subnet CIDR Calculator
Calculate network address, broadcast address, host range, subnet mask, and more from CIDR notation
- Home
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- Subnet CIDR Calculator
Quick Examples
Subnet Details
Network Address
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Broadcast Address
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Subnet Mask
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Wildcard Mask
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Total Hosts
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Usable Hosts
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Host Range
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Prefix Length
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IP Address (Binary)
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Subnet Mask (Binary)
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Subnet Mask (Hex)
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Enter a CIDR address and click Calculate
What Is CIDR Notation?
CIDR (Classless Inter-Domain Routing) notation specifies an IP address and its subnet prefix length using the format IP/prefix. For example, 192.168.1.0/24 means the first 24 bits are the network portion, leaving 8 bits for host addresses. This calculator helps network engineers plan and understand IP subnet allocations.
How to Use This Tool
- Enter CIDR notation — Type an IP address with prefix length (e.g., 192.168.1.0/24) into the input field.
- Click Calculate — The tool computes network address, broadcast address, subnet mask, wildcard mask, total hosts, usable hosts, and host range.
- Review details — Results are displayed in grid cards showing each calculated value. Binary representations of the IP and subnet mask are also shown.
- Try examples — Click the quick example buttons to load common CIDR notations and see their subnet details.
- Use for planning — The calculator helps with network segmentation, VLAN design, and IP address allocation planning.
Frequently Asked Questions
Is my data sent to a server?
No. All processing is performed locally in your browser. Your IP data never leaves your device.
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation uses the format IP/prefix where the prefix length indicates how many bits represent the network portion. For example, /24 means 24 network bits and 8 host bits.
What is the difference between total hosts and usable hosts?
Total hosts is 2^(32-prefix) for IPv4. Usable hosts subtracts 2 for the network and broadcast addresses, which cannot be assigned to devices.
Can I calculate IPv6 subnets?
This tool currently supports IPv4 subnetting only. IPv6 support may be added in the future.
Is this tool free to use?
Yes. This tool is completely free with no usage limits or registration required.
Last updated: 17 Aug 2026
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