IP Range Calculator

What this checks

• Start IP, end IP, total address count, and decimal boundaries.
• Whether the range is a single address and whether both ends are RFC 1918 private addresses.
• Minimal CIDR blocks that exactly cover the entered IPv4 range.

How to interpret results

• A single CIDR block means the range is aligned to a standard network boundary.
• Multiple CIDR blocks mean the start or end address cuts across normal CIDR boundaries.
• Private-only means both ends of the range are in RFC 1918 space, not that every possible mixed range is public-safe.

Common issues

• The start IP must be lower than or equal to the end IP.
• Only IPv4 ranges are supported; use the IPv6 decoder for IPv6 address analysis.

Privacy note

This IP range calculator runs entirely in the browser. The range you enter is not sent to the server.

Frequently Asked Questions

Can I enter a CIDR block instead of a start and end IP?

Yes. You can enter a start-end range such as 192.168.1.10 - 192.168.1.50 or a CIDR block such as 192.168.1.0/24.

What does CIDR coverage mean?

CIDR coverage is the smallest set of CIDR blocks that exactly covers the entered start and end IPv4 range.

Is the range sent to the server?

No. Range size and CIDR coverage are calculated locally in your browser.