IP Address Calculator
Calculate IP address ranges and network details.
Calculate IP address ranges and network details.
IPv4 calculation
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Tool guide
Free Online IP Address Calculator
Calculate IPv4 subnet details from an address and a CIDR prefix or contiguous subnet mask. Review the network address, broadcast address, masks, first and last usable addresses, and address counts directly in your browser.
Steps
How it works
- Enter an IPv4 address.
- Enter a CIDR prefix or dotted-decimal subnet mask.
- Run the network calculation.
- Copy or download the resulting IPv4 subnet details.
Highlights
Key features
- Accepts IPv4 addresses with prefixes from /0 through /32.
- Accepts contiguous dotted-decimal subnet masks.
- Calculates subnet and wildcard masks.
- Reports network and broadcast addresses.
- Shows first and last usable addresses plus total and usable address counts.
Use cases
Common uses
- Check the network block containing an IPv4 address.
- Convert a subnet mask into its CIDR prefix.
- Review broadcast and host-range boundaries while planning a subnet.
- Compare total addresses with conventionally usable addresses.
Notes
Limitations to know
- Only IPv4 is supported; IPv6 calculations are not included.
- For /31 and /32, the tool reports every address as usable instead of applying traditional network and broadcast exclusions.
- Private or public classification, binary output, address classes, geolocation, WHOIS, and DNS lookup are not provided.
- The result is mathematical and does not test reachability or scan a network.
- Network policies can use host-address conventions that differ from this calculation.
FAQ
Frequently asked questions
Can I enter CIDR notation?
Enter the IPv4 address in the address field and a prefix such as 24 or /24 in the subnet field.
Can I use a dotted subnet mask?
Yes. Contiguous masks such as 255.255.255.0 are accepted and converted to a prefix.
How is the broadcast address calculated?
The calculator sets every host bit in the normalized IPv4 network block to one.
How are /31 and /32 handled?
For these prefixes, total and usable counts are the same, and the calculated range is shown without subtracting network and broadcast addresses.
Does it identify an IP owner or location?
No. The tool performs offline subnet arithmetic only and makes no WHOIS, geolocation, DNS, or network request.