Subnet Calculator Lab
Practice subnetting calculations for the CompTIA A+ exam
IPv4 Subnet Calculator
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Network Address
192.168.1.0
Broadcast Address
192.168.1.255
Subnet Mask
255.255.255.0
Usable Host Range
192.168.1.1 - 192.168.1.254
Total Hosts
256
Usable Hosts
254
IP Class
Class C
IP Type
Private
Binary Representation (Network bits = purple, Host bits = green)
IP Address in Binary
Subnet Mask in Binary
Exam Tip: Quick CIDR Reference
/8 = 255.0.0.0 (Class A default) | /16 = 255.255.0.0 (Class B default) | /24 = 255.255.255.0 (Class C default)
Usable hosts formula: 2^(32 - CIDR) - 2 (subtract 2 for network and broadcast addresses)
Question 1 of 10
Score: 0/0
Calculate the Subnet Mask
192.168.1.0/24
What is the subnet mask for this CIDR notation?
Your Answer:
Quick Reference: Common Subnets
| CIDR | Subnet Mask | Usable Hosts | Common Use |
|---|---|---|---|
| /8 | 255.0.0.0 | 16,777,214 | Class A Default |
| /16 | 255.255.0.0 | 65,534 | Class B Default |
| /24 | 255.255.255.0 | 254 | Class C Default |
| /25 | 255.255.255.128 | 126 | Half /24 |
| /26 | 255.255.255.192 | 62 | Quarter /24 |
| /27 | 255.255.255.224 | 30 | Small Office |
| /28 | 255.255.255.240 | 14 | Very Small |
| /30 | 255.255.255.252 | 2 | Point-to-Point |
| /32 | 255.255.255.255 | 1 | Host Route |
