CIDR to IP Range Converter
Convert a CIDR block to its first and last IP and list every address, or turn an IP range into the minimal set of CIDR blocks. IPv4 and IPv6, in-browser.
Enter a CIDR (10.0.0.0/29) to get its range, or a range (10.0.0.1 - 10.0.0.20) to get the CIDR blocks that cover it.
| First address | 192.168.10.0 |
|---|---|
| Last address | 192.168.10.7 |
| Number of addresses | 8 |
| CIDR blocks | 192.168.10.0/29 |
192.168.10.0 192.168.10.1 192.168.10.2 192.168.10.3 192.168.10.4 192.168.10.5 192.168.10.6 192.168.10.7
What is CIDR to IP Range?
This converter expands a CIDR block such as 10.0.0.0/29 into its start address, end address, address count and, optionally, a full list of every IP in it. It also works in reverse: enter a range like 10.0.0.1 - 10.0.0.20 and it returns the smallest list of CIDR blocks that covers exactly that range. IPv4 and IPv6 are supported.
How to use CIDR to IP Range
- Enter a CIDR block (e.g.
192.168.10.0/29) or a range with a hyphen (e.g.10.0.0.1 - 10.0.0.6). - Keep "List every address" ticked to see each IP, one per line; untick it for very large blocks.
- Read the first address, last address, address count and CIDR blocks.
- Copy the address list or download it as a text file.
Example
10.0.0.1 - 10.0.0.6
10.0.0.1/32, 10.0.0.2/31, 10.0.0.4/31, 10.0.0.6/32 (6 addresses)
192.168.10.0/29 expands to 192.168.10.0 – 192.168.10.7 (8 addresses).
When to use CIDR to IP Range
Use it to build allow/deny lists, import ranges into firewalls that only accept CIDR, or check what a block in a cloud provider's IP list actually contains. For subnet details such as broadcast and usable hosts, use the Subnet Calculator instead.
How CIDR to IP Range works
Addresses are handled as big integers. For a CIDR block, the start is the address with the host bits cleared and the end is the start plus 2^(bits − prefix) − 1. For a range, the tool repeatedly takes the largest power-of-two block that both starts on an aligned boundary and does not extend past the end of the range, which yields the minimal CIDR set. Lists are capped at 1,024 addresses so a /8 or an IPv6 /64 cannot freeze the browser; the count is still shown exactly.
Common Use Cases
- Expand a /28 to paste the individual IPs into a monitoring tool.
- Convert a vendor-supplied range (start–end) into CIDR entries for an nginx allow list or AWS security group.
- Check how many addresses a /22 block contains before requesting it.
- Split an awkward range like .1–.10 into the exact CIDRs a router needs.
FAQs
Why is the list limited to 1,024 addresses?
Large blocks contain millions (IPv4 /8) or astronomically many (IPv6 /64) addresses. The tool always shows the exact count and range, but only lists the first 1,024 so the page stays responsive.
Does the list include the network and broadcast addresses?
Yes. This tool lists every address in the block. Use the Subnet Calculator if you need only the usable host range.
Can I mix IPv4 and IPv6 in a range?
No. Both ends of a range must be the same IP version; otherwise the tool shows an error.