Subnet / IP Calculator
Calculate network, broadcast, host range and subnet mask.
Calculation Results
| IP Address | |
|---|---|
| Network Address | |
| Usable Host Range | |
| Broadcast Address | |
| Subnet Mask | |
| Wildcard Mask | |
| CIDR Notation | |
| Usable Hosts | |
| Total Hosts | |
| IP Class |
1. How to use Subnet / IP Calculator
Subnet / IP Calculator is a powerful tool to help you calculate and manage network parameters quickly and accurately. Here are the steps to use the tool:
Steps to perform
- Enter IP Address: Enter the IP address you want to calculate in the main input field
- Choose Subnet Mask format: You can enter the subnet mask in CIDR format (e.g. /24) or dotted decimal format (e.g. 255.255.255.0)
- Click Calculate: The tool will automatically process and display the results in a few seconds
- View detailed results: Check information about network address, broadcast address, host range and number of usable hosts
- Copy results: Use the copy function to save important parameters
2. When to use Subnet / IP Calculator
Subnet / IP Calculator is an indispensable tool for network professionals, system administrators and IT engineers. Here are common situations:
- Enterprise Network Design: Plan IP and subnet allocation for new departments, branches or projects
- DHCP Infrastructure Management: Determine appropriate IP ranges for DHCP server configuration to avoid address conflicts
- Router and Firewall Configuration: Set up routing rules, ACLs and firewalls based on accurate subnet information
- Network Troubleshooting: Check if two devices are in the same subnet to determine connection issues
- Learning and Training: Better understand the structure of TCP/IP networks and how subnet masking works
- Network Security Audit: Analyze IP ranges to identify sensitive network areas that need protection
3. Technical Information
To use the Subnet / IP Calculator effectively, you need to understand the basic concepts of TCP/IP networks:
Key Concepts
- Subnet Mask: A 32-bit sequence used to determine the network and host portions of an IP address. '1' bits represent the network, '0' bits represent the host
- CIDR Notation: A shorthand for subnet masks, e.g. /24 means the first 24 bits are network, the remaining 8 bits are host
- Network Address: The first address in a subnet, used to identify the entire subnetwork
- Broadcast Address: The last address in the subnet, used to send data to all devices in the network
- Usable Host Range: The set of IP addresses that can be assigned to devices, excluding the network and broadcast addresses
- Class-based Addressing: The legacy IP classification system (Class A, B, C) based on the first octet, now replaced by CIDR
- Subnetting: The process of dividing a large network into smaller subnetworks to optimize IP usage
Practical Examples
- Example 1: IP 192.168.1.0/24 has network address 192.168.1.0, broadcast 192.168.1.255, and 254 usable hosts from 192.168.1.1 to 192.168.1.254
- Example 2: IP 10.0.0.0/8 is a Class A network with 16,777,214 usable hosts, commonly used for large enterprise networks
4. Subnet Mask & CIDR Reference Table
The subnet mask determines which part of the IP address is network and which is host. CIDR notation (e.g. /24) indicates the number of network bits. The table below provides a quick reference between CIDR, subnet mask and usable hosts.
| CIDR | Subnet Mask | Usable Hosts |
|---|---|---|
| /30 | 255.255.255.252 | 2 |
| /29 | 255.255.255.248 | 6 |
| /28 | 255.255.255.240 | 14 |
| /27 | 255.255.255.224 | 30 |
| /26 | 255.255.255.192 | 62 |
| /25 | 255.255.255.128 | 126 |
| /24 | 255.255.255.0 | 254 |
| /23 | 255.255.254.0 | 510 |
| /22 | 255.255.252.0 | 1022 |
| /16 | 255.255.0.0 | 65534 |
How to calculate subnet mask and IP allocation
Usable hosts = 2(32 − network bits) − 2 (subtracting network and broadcast addresses). For example, /24 has 8 host bits, so 28 − 2 = 254 hosts. Enter IP address and CIDR into the tool above to automatically calculate network, broadcast, host range and subnet mask.
Frequently Asked Questions
A /24 subnet mask provides 254 usable hosts. There are 256 total IP addresses, but the first address is the Network Address and the last is the Broadcast Address.
CIDR (e.g. /24) represents the number of consecutive '1' bits in the subnet mask. An IP address has 32 bits. /24 means the first 24 bits are 1, and the remaining 8 bits are 0. Converted to binary: 11111111.11111111.11111111.00000000, which equals 255.255.255.0.
With /25, the subnet mask is 255.255.255.128. The network address for 192.168.1.100/25 is 192.168.1.0, the usable host range is from 192.168.1.1 to 192.168.1.126, and the broadcast address is 192.168.1.127.
Calculating subnets helps divide a large network into smaller subnetworks (subnetting) to enhance security, reduce network congestion (smaller broadcast domains), and manage IP resources more efficiently by preventing IP waste.
Currently, this tool focuses on calculations for IPv4, as it is the most common standard for subnetting and internal network design.
About Subnet / IP Calculator
Subnet / IP Calculator is a powerful tool to help you calculate and manage network parameters quickly and accurately.
Calculate the network address, broadcast address, subnet mask, wildcard mask, usable host range, and address counts from an IPv4 address and CIDR prefix.
Key features
- Diagnostic scope Calculate the network address, broadcast address, subnet mask, wildcard mask, usable host range, and address counts from an IPv4 address and CIDR prefix.
- Target input Enter a valid IPv4 host address and either a prefix length such as /24 or the corresponding subnet mask.
- Checks to review Change CIDR or mask to compare subnet sizes and inspect binary or hexadecimal representations where available.
- Diagnostic result The result derives the containing network, address range, conventional usable hosts, masks, and capacity for network planning.
How to use Subnet / IP Calculator
Follow this workflow to work with IPv4 subnet boundaries safely and accurately.
- Enter the target Enter a valid IPv4 host address and either a prefix length such as /24 or the corresponding subnet mask.
- Select the diagnostic scope Change CIDR or mask to compare subnet sizes and inspect binary or hexadecimal representations where available.
- Run the network check Run the IPv4 subnet boundaries diagnostic and retain status, timing, returned values, and the observation point needed to reproduce it.
- Correlate the result The result derives the containing network, address range, conventional usable hosts, masks, and capacity for network planning.
Usage tips
- Remember that /31 is commonly used for point-to-point links and /32 identifies a single host.
- Reserve gateway, infrastructure, DHCP, and growth space before assigning application hosts.
- Check for overlap with VPN, cloud VPC, container, and on-premises ranges.
Frequently asked questions
Calculate the network address, broadcast address, subnet mask, wildcard mask, usable host range, and address counts from an IPv4 address and CIDR prefix.
Enter a valid IPv4 host address and either a prefix length such as /24 or the corresponding subnet mask.
Change CIDR or mask to compare subnet sizes and inspect binary or hexadecimal representations where available.
The arithmetic cannot know platform-specific reserved addresses, route policy, VLAN design, or whether overlapping private ranges are reachable through NAT or VPN.