1. What is Subnet Mask?

A subnet mask is a 32-bit number that divides an IP address into network and host portions. It's used to determine which part of an IP address belongs to the network and which part belongs to the host.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Hosts \) — Number of required hosts in the subnet
• \( +2 \) — Accounts for network and broadcast addresses
• \( \log_2 \) — Binary logarithm to determine required bits
• \( 32 \) — Total bits in an IPv4 address

Explanation: The formula calculates the minimum number of host bits needed to accommodate the specified number of hosts, then determines the corresponding subnet mask.

3. Importance of Subnet Mask

Details: Proper subnet mask calculation is essential for efficient IP address allocation, network segmentation, and routing. It helps prevent IP address exhaustion and optimizes network performance.

4. Using the Calculator

Tips: Enter the number of hosts you need to accommodate in the subnet. The calculator will determine the appropriate subnet mask in both dotted-decimal and CIDR notation.

5. Frequently Asked Questions (FAQ)

Q1: Why add 2 to the number of hosts?
A: The formula adds 2 to account for the network address (all 0s) and broadcast address (all 1s) which cannot be assigned to hosts.

Q2: What is CIDR notation?
A: CIDR (Classless Inter-Domain Routing) notation represents the subnet mask as a slash followed by the number of network bits (e.g., /24).

Q3: What's the maximum number of hosts in a subnet?
A: The maximum is 2^(32 - mask_bits) - 2. For example, a /24 subnet (255.255.255.0) supports 254 hosts.

Q4: Can I use this for IPv6?
A: No, this calculator is for IPv4 only. IPv6 uses a different addressing scheme.

Q5: What if I need multiple subnets with different host counts?
A: Calculate each subnet separately, ensuring the sum of all hosts plus their network/broadcast addresses fits within your available address space.