IPv6 Range to CIDR
Convert a start and end IPv6 address into the smallest list of CIDR blocks.
IPv4 ranges work too, such as 192.168.0.10 to 192.168.1.20.
Continue your work
- IPv6 CIDR to Range — Check the range of each block.
- IPv4 Subnet Calculator — Explore an IPv4 subnet in detail.
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Clear instructions
Find steps, examples and limitations below.
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How to use the IPv6 Range to CIDR
Convert a start and end IPv6 address into the smallest list of CIDR blocks.
- 1 Enter the first address of the range.
- 2 Enter the last address of the range.
- 3 Copy the list of CIDR blocks and the address count shown above it.
Example and practical tips
The range 192.168.0.10 to 192.168.0.20 needs four blocks: 192.168.0.10/31, 192.168.0.12/30, 192.168.0.16/30 and 192.168.0.20/32.
Frequently asked questions
Why can one range need several blocks?
A CIDR block must start on a boundary that matches its size, so ranges that do not line up are split into several blocks.
Does it work for IPv4?
Yes. If the start address is IPv4, the range is calculated as IPv4.
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