CIDR to Range
CIDR to Range translates an IPv4 address and prefix length into the containing network boundary, broadcast boundary, and total number of addresses. It performs bitmask arithmetic locally. The total includes every address in the block and does not subtract network, broadcast, gateway, or provider-reserved addresses.
Runs locally — files stay on your deviceWhat range does 192.168.1.42/24 describe?
Network 192.168.1.0, broadcast 192.168.1.255, with 256 total addresses.
A CIDR prefix fixes the leading network bits
IPv4 has 32 bits. A /p prefix keeps p network bits and leaves 32−p host bits, producing 2^(32−p) total addresses.
How it works
Enter an IPv4 address followed by /0 through /32. The tool constructs the subnet mask, clears host bits for the network, sets them for the broadcast address, and reports the block size.
Key concepts
Any address inside the block is accepted
Host bits are masked to derive the network boundary.
Total and usable counts differ
Usability depends on prefix and network platform policy.
When to use it
- Find the boundaries containing a host address.
- Check subnet plans.
- Calculate the raw size of an IPv4 block.
When not to use it
- Do not treat total addresses as universally usable hosts.
- Do not use this IPv4 tool for IPv6 prefixes.
- Do not assume the input address must already be the network boundary.
Worked examples
Typical /24
- Input
192.168.1.42/24- Expected output
192.168.1.0–192.168.1.255; 256 addresses
Eight host bits remain.
Single address
- Input
203.0.113.9/32- Expected output
Network and broadcast 203.0.113.9; 1 address
No host bits remain.
Two-address block
- Input
198.51.100.2/31- Expected output
198.51.100.2–198.51.100.3; 2 addresses
One host bit remains.
Common mistakes
Calling total addresses usable hosts
Traditional subnets reserve boundaries, while /31 and /32 have special uses. Correction: Apply the rules of the actual platform.
Using a netmask instead of a prefix
The input expects slash notation. Correction: Use a value such as /24.
Entering IPv6
The implementation uses 32-bit IPv4 arithmetic. Correction: Use an IPv6-aware prefix calculator.
Best practices
- Record both prefix and range.
- Check overlap before deployment.
- Apply environment-specific usable-address rules.
Related operations and differences
IP Address Validator
Choose IP Address Validator when you need to validate IPv4 or basic IPv6 syntax.; use CIDR to Range specifically for cidr range.
Private IP Checker
Choose Private IP Checker when you need to check common private and reserved IPv4 ranges.; use CIDR to Range specifically for cidr range.
cURL Command Builder
Choose cURL Command Builder when you need to build a basic cURL command from manual fields.; use CIDR to Range specifically for cidr range.
DMARC Record Generator
Choose DMARC Record Generator when you need to generate a basic DMARC policy record.; use CIDR to Range specifically for cidr range.
Fetch Request Builder
Choose Fetch Request Builder when you need to build a browser fetch request snippet.; use CIDR to Range specifically for cidr range.
HTTP Header Formatter
Choose HTTP Header Formatter when you need to normalize spacing in pasted HTTP headers.; use CIDR to Range specifically for cidr range.
Limitations and privacy
- IPv4 only.
- Reports raw total addresses, not provider-specific usable capacity.
- Does not detect overlap with other networks or fetch routing data.
The entered network data is processed locally in this browser.
Frequently asked questions
Must the input be the network address?
No.
Are network and broadcast included in the total?
Yes.
What does /32 mean?
A single IPv4 address.
Does it support IPv6?
No.