IPv4 Subnetting Worksheets
Generate custom IPv4 subnetting practice worksheets with answer keys. Perfect for networking students preparing for CCNA, Network+, or other certifications. Create multiple worksheet versions for classroom use.
Worksheet Settings
Each version will have 10 different questions labeled A, B, C, etc.
Worksheet Preview
Note: The PDF will include all worksheet versions followed by all answer keys.
How to Use the Worksheet Generator
- Choose number of versions: Select how many different worksheet versions you need (1-26, labeled A-Z).
- Select CIDR range: Choose between any CIDR, classful boundaries, or common subnet ranges.
- Choose mask format: Select CIDR notation, decimal notation, or mixed format.
- Generate: Click "Generate Worksheets" to create your practice problems.
- Download PDF: Save the worksheets with answer keys as a PDF file.
What You'll Calculate
Network Address
The first IP address in a subnet, used to identify the network itself. All host bits are set to 0.
Broadcast Address
The last IP address in a subnet, used to send messages to all hosts on the network. All host bits are set to 1.
First Usable Address
The first IP address that can be assigned to a host device (network address + 1).
Last Usable Address
The last IP address that can be assigned to a host device (broadcast address - 1).
Total Addresses
The total number of IP addresses in the subnet, including network and broadcast addresses (2^host bits).
Usable Addresses
The number of addresses that can be assigned to hosts (total addresses - 2, excluding network and broadcast).
Features
✓ Multiple Versions
Generate up to 26 different worksheet versions (A-Z) for classroom use or extra practice.
✓ Answer Keys Included
PDF includes both worksheets and answer keys for easy grading and self-study.
✓ Customizable Difficulty
Choose between any CIDR, classful boundaries, or common ranges to match skill level.
✓ Flexible Notation
Practice with CIDR notation, decimal notation, or a mix of both formats.
✓ Complete Coverage
Each question requires calculating 6 values: network, broadcast, first/last usable, total and usable addresses.
✓ Optimized Layout
Questions spread across full page height in two columns with ample writing space.
Subnetting Tips & Tricks
- Know your powers of 2: Memorize 2^1 through 2^8 (2, 4, 8, 16, 32, 64, 128, 256) for quick calculations.
- Subnet mask shortcut: For /24, the mask is 255.255.255.0. Each bit borrowed adds 128, 64, 32, 16, 8, 4, 2, 1 in the next octet.
- Block size method: Calculate block size as 256 minus the interesting octet value (e.g., 256 - 192 = 64).
- Practice binary: Understanding binary makes subnetting much easier, especially for non-standard masks.
- Common CIDR values: Memorize /24 (254 hosts), /25 (126 hosts), /26 (62 hosts), /27 (30 hosts), /28 (14 hosts), /29 (6 hosts), /30 (2 hosts).
- Usable hosts formula: 2^(32 - CIDR) - 2 (subtract 2 for network and broadcast addresses).
- Network increments: Networks increment by the block size in the interesting octet.
Common Use Cases
- CCNA preparation: Practice essential subnetting skills required for Cisco CCNA certification.
- Network+ study: Master IP addressing concepts for CompTIA Network+ exam.
- Classroom assignments: Teachers can generate unique versions for each student to prevent copying.
- Homework practice: Students can generate unlimited practice problems with instant answer checking.
- Certification prep courses: Instructors can create standardized assessments for networking courses.
- Self-study: IT professionals can brush up on subnetting skills for interviews or job requirements.
- Technical interviews: Practice common subnetting questions asked in networking job interviews.
- Team training: Network administrators can train junior staff on IP addressing fundamentals.
Understanding CIDR Ranges
Any CIDR (/6 to /30)
Includes all subnet masks from /6 (67,108,862 hosts) down to /30 (2 hosts). Most challenging option with maximum variety including supernets.
Class Boundaries (/8, /16, /24)
Traditional classful addressing: Class A (/8), Class B (/16), and Class C (/24). Easier calculations with octet-aligned boundaries.
Common Ranges
Focuses on subnet masks frequently used in real-world networks: /16, /20, /22, /24, /25, /26, /27, /28, /29, /30. Balances practical relevance with variety.
Frequently Asked Questions
How many questions are on each worksheet?
Each worksheet contains 10 questions arranged in two columns of 5 questions each for optimal layout and readability.
Are the answer keys on separate pages?
Yes, the PDF is organized with all worksheet versions first, followed by all answer keys. For example, with 3 versions: pages 1-3 are worksheets A-C, pages 4-6 are answer keys A-C.
What's the difference between CIDR and decimal notation?
CIDR notation uses a slash and number (e.g., /24) to indicate how many network bits. Decimal notation shows the full subnet mask (e.g., 255.255.255.0). Both represent the same thing.
Can I generate new worksheets with the same settings?
Yes! Each time you click "Generate Worksheets," completely new random IP addresses and questions are created, even with the same settings.
Which CIDR range should beginners use?
Start with "Class Boundaries" for easiest calculations with octet-aligned masks. Progress to "Common Ranges" for practical scenarios, then "Any CIDR" for comprehensive practice.
Are these suitable for certification exams?
Yes! These worksheets cover the types of subnetting calculations required for CCNA, Network+, and similar networking certifications.
Can I use these for commercial training?
Generated worksheets are free for classroom and personal use. Commercial resale or publication is not permitted. Teachers and trainers can freely use them in educational settings.
Quick Reference: Common Subnet Masks
| CIDR | Subnet Mask | Usable Hosts | Common Use |
|---|---|---|---|
| /8 | 255.0.0.0 | 16,777,214 | Class A networks |
| /16 | 255.255.0.0 | 65,534 | Class B networks, large organizations |
| /24 | 255.255.255.0 | 254 | Class C networks, small LANs |
| /25 | 255.255.255.128 | 126 | Small office networks |
| /26 | 255.255.255.192 | 62 | Department networks |
| /27 | 255.255.255.224 | 30 | Small office segments |
| /28 | 255.255.255.240 | 14 | Workgroups |
| /29 | 255.255.255.248 | 6 | Small segments |
| /30 | 255.255.255.252 | 2 | Point-to-point links |
