CIDR Calc

IP range to CIDR, instantly.

Convert any IPv4 range into the minimal set of CIDR blocks that exactly covers it. No extra addresses.

Open range calculatorFull calculator

How it works

  1. Enter a start and end IPv4 address.
  2. We split the range into the fewest CIDR blocks possible.
  3. Copy the CIDRs or share the link.

Example

192.168.1.10 – 192.168.1.20

Result

192.168.1.10/31, 192.168.1.12/30, 192.168.1.16/30, 192.168.1.20/32

Tip

Use CIDR blocks to feed firewall rules, ACLs, or routing tables without expanding your address space.