AWS and DevOps
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Visual IP Subnet Calculator & CIDR Reference
Calculate IPv4 subnets, CIDR prefix masks, network and broadcast addresses, usable host ranges, and wildcard masks. Includes a 32-bit binary bitmask visualizer and interactive CIDR quick reference table. Runs 100% locally in your browser.
Presets:
Network Address
192.168.1.0
First IP of subnet
Broadcast Address
192.168.1.255
Reserved broadcast IP
Usable Host IPs
254
Total: 256
IP Designation
Private (RFC 1918)
Class C
Calculated Address Parameters
- Subnet Mask:
- 255.255.255.0
- Wildcard Mask:
- 0.0.0.255
- First Usable Host:
- 192.168.1.1
- Last Usable Host:
- 192.168.1.254
32-Bit Binary Bitmask Visualization
IP Binary:11000000101010000000000101100100
Mask Binary:11111111111111111111111100000000
CIDR Subnet Reference Table
| Prefix | Subnet Mask | Total IPs | Usable Hosts |
|---|---|---|---|
| /8 | 255.0.0.0 | 16,777,216 | 16,777,214 |
| /16 | 255.255.0.0 | 65,536 | 65,534 |
| /20 | 255.255.240.0 | 4,096 | 4,094 |
| /24 | 255.255.255.0 | 256 | 254 |
| /25 | 255.255.255.128 | 128 | 126 |
| /26 | 255.255.255.192 | 64 | 62 |
| /27 | 255.255.255.224 | 32 | 30 |
| /28 | 255.255.255.240 | 16 | 14 |
| /29 | 255.255.255.248 | 8 | 6 |
| /30 | 255.255.255.252 | 4 | 2 |
| /31 | 255.255.255.254 | 2 | 2 |
| /32 | 255.255.255.255 | 1 | 1 |
01
How to use
- Enter an IPv4 address and CIDR prefix (e.g. 10.0.0.1/16 or 192.168.1.100/24).
- Inspect the calculated Network Address, Broadcast Address, Usable Host Range, Subnet Mask, and Wildcard Mask.
- View the 32-bit binary bitmask breakdown showing network prefix bits vs host bits.
- Use the interactive CIDR reference table to quickly look up host counts and subnet masks from /0 to /32.
02
Understanding the output
Subnetting divides IP networks into smaller sub-networks. The CIDR prefix length (e.g. /24) defines how many bits represent the network prefix, while the remaining bits determine host addresses. Standard subnets reserve the first address for the Network and the last for Broadcast.
03
Common issues & tips
- •Invalid IP address syntax: IPv4 requires 4 octets between 0 and 255 (e.g. 172.16.0.1).
- •Invalid CIDR prefix: prefix length must be an integer from 0 to 32.
- •/31 subnets follow RFC 3021 point-to-point links (2 usable hosts, no broadcast). /32 designates a single host route.
Frequently asked questions
- Does this calculator support IPv6?
- This version is dedicated to IPv4 subnetting. An IPv6 subnet calculator will be added in a future update.
- How are /31 and /32 subnets handled?
- /31 subnets follow RFC 3021 point-to-point links (2 usable hosts). /32 designates a single host route.