Developer & Data tool
IP & Subnet Calculator
Use an IP address and prefix to find its network range and address count.
Counts are mathematical; cloud-provider reservations and device allocation policies are excluded.
IP & subnet calculatorCalculate network ranges and address counts from CIDR notation.
IPv4 · IPv6Without a prefix, IPv4 defaults to /32 and IPv6 to /128.
| Input address | 192.168.1.25 |
|---|---|
| Network CIDR | 192.168.1.0/24 |
| First address | 192.168.1.0 |
| Last address | 192.168.1.255 |
| Subnet mask | 255.255.255.0 |
| Wildcard mask | 0.0.0.255 |
| Broadcast | 192.168.1.255 |
| First host | 192.168.1.1 |
| Last host | 192.168.1.254 |
IPv4 /31 counts both point-to-point addresses; /32 is one address. IPv6 has no broadcast. Provider reservations and device allocation policies are not included.
Read a network range
Find the subnet containing an address
Enter the address and prefix
Use a value such as 192.168.1.25/24. Both IPv4 and IPv6 are supported; omitting the prefix calculates a single-address range.
Compare range and mask
Read the network CIDR, first and last addresses, and subnet mask together. IPv4 also shows the wildcard mask and host endpoints.
Distinguish counts from capacity
Compare total addresses with host capacity. /31 and /32 have special rules, and IPv6 does not have broadcast addresses.
A worked example
An office /24 subnet
- Start with
- 192.168.1.25/24
- Check the result
- 192.168.1.0–192.168.1.255; 256 total addresses and 254 hosts
The host range is .1–.254 and the mask is 255.255.255.0. Operational reservations may further reduce usable capacity.