IPv4 & IPv6 CIDR Subnet Calculator
/
| Network Address | |
|---|---|
| Subnet Mask | |
| Broadcast Address | |
| First Usable Host | |
| Last Usable Host | |
| Total Usable Hosts |
Invalid IP Address or CIDR prefix. Please enter a valid IPv4 address and prefix between 0 and 32.
Introduction
Instantly calculate usable IP ranges, broadcast addresses, and subnet masks for your server architecture and cloud VPC routing rules.
What is the CIDR Calculator and Why Use It?
When provisioning cloud infrastructure on AWS, Google Cloud, or configuring firewalls, network routing is defined using CIDR (Classless Inter-Domain Routing) blocks like `192.168.1.0/24`. Attempting to manually calculate the binary mathematics for subnet masks, network boundaries, and usable host limits is complex and risky. Our CIDR Subnet Calculator handles the bitwise operations for you instantly. Enter your IP and suffix to get a complete breakdown of your network topology, executed safely right in your browser.
Key Features
- 100% Client-Side Privacy: Network topologies are highly confidential. Our tool performs all binary calculations locally so your infrastructure map remains private.
- IPv4 & IPv6 Support: Fully supports traditional IPv4 subnets as well as complex IPv6 hexadecimal routing configurations.
- Instant Range Mapping: Immediately displays the First Usable IP, Last Usable IP, Network Address, and Broadcast Address.
- Maximum Host Calculation: Accurately subtracts reserved network/broadcast IPs to tell you exactly how many servers can fit in the subnet.
How to Use the Subnet Calculator (Step-by-Step)
- Step 1: Enter your base IP address into the input field.
- Step 2: Provide the CIDR suffix (the number after the slash, e.g., `24` or `16`).
- Step 3: Review the generated network table, and copy the IP range directly into your AWS VPC or firewall configuration.
Frequently Asked Questions
The `/24` dictates that the first 24 bits of the IP address are locked as the network identifier, leaving 8 bits for the hosts. This equates to 256 total IP addresses, or 254 usable addresses for devices.
In IPv4 subnets, the very first address is reserved as the Network Identifier, and the very last address is reserved as the Broadcast address. They cannot be assigned to servers.
No. DevToolbox performs all subnet calculations inside your local browser. Your network architecture is never tracked.