IPv4 Subnet Calculator
Local ProcessingNetwork, broadcast, host range and count, and subnet mask from a CIDR.
How It Works & Processing Standards
Network, broadcast, host range and count, and subnet mask from a CIDR.
Tool processing runs in your browser. If you create a calculator or conversion share link, its values are included in the URL. See the privacy policy for account, analytics and advertising data.
Current Limits
- Maximum input length: 100,000 characters
The "/number" in CIDR is how many leading bits belong to the network. Choose a full calculation, address range, host count or CIDR ↔ mask under "Task" to see just what you need.
What You Can Do
- CIDR calculation
- Network, broadcast, mask, first/last host and host count at once.
- IP range and host count
- Only the start/end address or the usable host count.
- CIDR ↔ mask
- Converts between /26 and 255.255.255.192.
How to Use IPv4 Subnet Calculator
- 1Choose a taskPick the calculation you need.
- 2Enter CIDR or maskFor example 192.168.1.0/24, 26 or 255.255.240.0.
- 3Read the resultCopy the addresses and counts.
Examples
Full /24 calculation
Input: 192.168.1.0/24
Result: Network 192.168.1.0, broadcast 192.168.1.255, mask 255.255.255.0, hosts 192.168.1.1 – 192.168.1.254 (254)
/22 host count
Input: 10.0.0.0/22
Result: 1,024 total, 1,022 usable
Prefix → mask
Input: 26
Result: 255.255.255.192
Mask → prefix
Input: 255.255.240.0
Result: /20
Range from an address inside the block
Input: 172.16.5.130/27
Result: 172.16.5.128 – 172.16.5.159 (32)
Common Use Cases
- Splitting office networks or cloud VPC subnets
- Checking address ranges for firewall or security-group rules
- Verifying subnetting answers for certification study
Frequently Asked Questions (FAQ)
Why are there two fewer usable hosts?
The first address (network) and the last (broadcast) cannot be assigned to devices. /31 and /32 are treated as exceptions.
Can I enter an address in the middle, like 192.168.1.77/24?
Yes. The tool calculates from the block the address belongs to (192.168.1.0/24).