IP Address Info & Subnet Calculator
Look up IP address information and calculate subnet details, CIDR notation, and network ranges.
Fetching your public IP...
Subnet Calculator
About this calculator
Enter a network in CIDR form, such as 192.168.1.0/24, and see its mask, range and host count. The page also tries to show your public IP.
Useful for home networks, office subnets and cloud VPC planning.
How to use it
- Enter the CIDR.
- Press Calculate.
- Read the network details.
CIDR basics
CIDR (Classless Inter-Domain Routing) writes an address and its prefix: 10.0.0.0/8 covers 16,777,216 addresses; 192.168.1.0/24 covers 256. A /24 has 254 usable hosts, a /25 has 126, /26 has 62, /27 has 30, /28 has 14 and /29 has 6.
Worked example
192.168.1.0/24
| Mask | 255.255.255.0 |
| Usable hosts | 254 |
| Broadcast | 192.168.1.255 |
Tips and common mistakes
- Private addresses are not routable on the internet.
- Your public IP is assigned by your ISP and may change.
- Use /30 for point-to-point links.
- Document your IP plan.
- IPv6 uses 128-bit addresses and /64 subnets.
Frequently asked questions
What does /24 mean?
The first 24 bits are the network.
How many hosts in a /28?
14.
What is a public IP?
The address the internet sees for your connection.
What is a private IP?
An address used inside a local network.
Is my IP private?
Addresses starting 192.168, 10 or 172.16 to 31 are private.
Is it free?
Yes.