↔️ IP Range Calculator
Enter a start and end IPv4 address to see the total address count and the CIDR blocks that cover the range.
Input
Results
First IP
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Last IP
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Total Addresses
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Covering CIDR Blocks
| CIDR Block | Size |
|---|
How It Works
Not every range of IP addresses aligns neatly to a single CIDR block. This tool finds the smallest set of CIDR blocks that exactly covers your range, using the standard "largest aligned block first" algorithm: at each step it finds the biggest power-of-two block that starts at the current address and doesn't overshoot the end of the range.
Examples & Common Use Cases
- 192.168.1.10 → 192.168.1.100 → 91 addresses, summarized as several CIDR blocks.
- A range that starts and ends exactly on a power-of-two boundary summarizes to a single CIDR block.