IPv4 Range Expander
Expand a CIDR block or start-end pair into its full IP range.
Addresses
Frequently asked questions
What does expanding an IP range do?
It lists every individual IPv4 address contained in a CIDR block or a start-to-end range. This turns a compact notation into the full set of addresses.
What is CIDR notation?
CIDR notation writes a network as an address followed by a slash and a prefix length, such as 192.168.0.0 slash 24, where the prefix says how many bits are fixed. The remaining bits define the range of host addresses.
How many addresses does a slash 24 contain?
A slash 24 block contains 256 addresses, from the network address through the broadcast address. Smaller prefix numbers cover far more addresses.
Why is there a cap on very large ranges?
Enormous ranges could contain millions of addresses and overwhelm the browser and the display, so the tool caps the output to keep it responsive. You can narrow the range to see specific addresses.
Can I use a start and end address instead of CIDR?
Yes. You can provide a start address and an end address, and the tool expands every address in between. This helps when the range does not fall on a clean CIDR boundary.
Is my input sent to a server?
No. The expansion is computed entirely in your browser, so the ranges you enter are never uploaded. It runs locally.
Does the expanded list include the network and broadcast addresses?
A full CIDR expansion includes every address in the block, including the network and broadcast addresses at the ends. Whether those are usable as hosts depends on the network configuration.