What this tool does
The IP Range Calculator defines the start address as the network address and the end address as the broadcast address. Even for 10.0.0.0/8 or /0, it displays only the boundaries and counts instead of generating millions or billions of addresses.
- Range endpoints are calculated as unsigned 32-bit values.
- For /31, both endpoints are shown under RFC 3021 point-to-point semantics; for /32, the start and end are identical.
- The tool does not scan, connect to, or check the online status of any address in the range.
How to use it
- Enter an IPv4 address or a complete CIDR block.
- Enter the prefix in the second field if needed.
- Click Calculate IP Range.
- View the start address, end address, usable range, and address count.
How it works
The CIDR mask clears the IP address’s host bits to produce the start of the range; setting those host bits to 1 produces the end. The address count is calculated directly as 2^(host bits), without iterating over individual addresses.
Examples
- 192.168.1.100/24 → 192.168.1.0–192.168.1.255; the traditional usable range is .1–.254.
- 10.0.0.0/8 → 16,777,216 addresses total; only the start, end, and count are displayed.
- 192.168.1.10/32 → Both the start and end are 192.168.1.10.
Common uses
- Confirm the boundaries covered by a firewall rule or address pool.
- Compare a CIDR block's total address count with its traditional usable-host count.
- Inspect the range of a large network safely without creating an address list.
Privacy
Inputs and results are processed only in local browser memory. Nothing is uploaded, sent to an online API, or stored automatically.
IP Range Calculator Features
Calculate a CIDR block's start and end addresses, usable range, and counts without expanding it into a large IP list. Useful for network planning, configuration checks, and troubleshooting; results can be reviewed and copied immediately.
FAQ
How do I calculate the IP range of a CIDR block?
Apply the subnet mask to the IP address to get the start, then set the wildcard bits to 1 to get the end.
Is the network address part of the IP range?
Yes. This page defines it as the start address of the range.
Is the broadcast address part of the IP range?
Yes. In the traditional subnet model, it is the end address of the range.
Why not list every IP address in a large CIDR block?
A /0 contains 4,294,967,296 addresses. Enumerating them would exhaust browser memory and serves no purpose.