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IP Range to CIDR Converter

Convert an IPv4 range into the minimal list of CIDR blocks, or CIDR blocks into IP ranges.

Runs instantly in your browser — results update as you type.

How do I convert an IP range to CIDR?

Enter the range as start – end and the converter splits it into the fewest CIDR blocks that cover exactly those addresses. For example 192.168.1.0 – 192.168.1.130 becomes 192.168.1.0/25, 192.168.1.128/31 and 192.168.1.130/32.

Uses

  • Firewall and security group rules that only accept CIDR notation.
  • Allow-lists for cloud services and CDNs.
  • Converting ISP-provided ranges for router configuration.

For details of a single subnet, use the IP Subnet Calculator.

Frequently asked questions

Does it support IPv6?

This tool handles IPv4.

Can I convert several CIDRs at once?

Yes, enter them separated by spaces, commas or new lines.

Is it free?

Yes.