Network
IP / Subnet Calculator
IPv4 · CIDR · Address ranges
Find an IPv4 subnet, choose a size for the IP addresses you need, or split an address range into CIDRs.
Processed locally in your browser. Input is not uploaded or saved.
Result
IPv4: 8 bits × 4 groups
Filled: Network bits · Outlined: Host bits
Details and terminology
Why are two addresses excluded?
In conventional /0–/30 subnets, one address identifies the network and one is the broadcast address. /31 point-to-point links can use both addresses (RFC 3021); /32 identifies one host and has no subnet broadcast.
/24 → 256 · /25 → 128 · /26 → 64 · /27 → 32 · /28 → 16
Usage guideWhen to use · Examples · Understand results
When to use this tool
Find the subnet of an IPv4 address, plan capacity for required IP addresses, or describe a start/end range accurately as CIDRs.
How to use it
- Choose IP/CIDR, required address count or start/end range. For example, enter 192.168.10.35/27 and calculate.
- IPv4 has 32 bits in four groups of eight. /27 means the first 27 cells are network bits; the remaining 5 are host bits. Five host bits represent 2⁵ = 32 addresses. Change the CIDR slider to see the boundary move.
Examples
IPv4 / CIDR
- Input
192.168.10.35/27
- Expected result
192.168.10.32 ~ 192.168.10.63 192.168.10.33 ~ 192.168.10.62 255.255.255.224 Total 32 · Usable 30 · Network 27 bit · Host 5 bit
Reading the result
The full range contains every address. In /0–/30 conventional subnets, the network and broadcast addresses leave two fewer generally usable addresses. /31 uses both addresses on a point-to-point link; /32 identifies one host and has no subnet broadcast. Required address sizing uses conventional subnets and excludes these exceptions.