Use values such as 10.0.0.0/8 or 192.168.1.0/24.
IP utility
IPv4 range & CIDR calculator
Explore a CIDR block or turn an arbitrary IPv4 start/end range into the smallest set of CIDR blocks that covers it exactly.
Quick guide
CIDR and address ranges
CIDR expresses a contiguous IP block with an address and prefix length. A /24 contains 256 IPv4 addresses, while a /32 contains exactly one.
When you enter a start/end range, IPGetter calculates the smallest exact set of aligned CIDR blocks covering that range without including addresses outside it.
Use two IPv4 addresses separated by a hyphen.
Useful for firewall rules, allowlists and route summaries.
IPGetter converts the start and end IPv4 addresses into integers, validates the range, then finds the smallest set of CIDR blocks that covers it exactly.
- Summarising firewall allow-lists
- Turning address ranges into CIDR blocks
- Checking the size and boundaries of an IPv4 range
Terminal shortcut
Prefer the command line?
Summarize an IPv4 range into minimal CIDR blocks.
> range 192.168.1.10 192.168.1.25
Run in Terminal ->