1. What is Subnet Calculation?

Subnet calculation is the process of dividing a network into smaller network segments called subnets. This helps in efficient IP address allocation, improved network security, and reduced network congestion.

2. How Does the Calculator Work?

The calculator uses the subnet calculation formula:

Where:

• \( New\ mask \) — The new subnet mask in bits (CIDR notation)
• \( Old\ mask \) — The original network mask in bits

Explanation: The formula calculates how many times a network can be divided by borrowing bits from the host portion of the IP address.

3. Importance of Subnet Calculation

Details: Proper subnetting is essential for network design, allowing efficient use of IP address space, creating broadcast domains, and implementing network security policies.

4. Using the Calculator

Tips: Enter the original network mask and the new subnet mask (must be equal or larger than the original). Both values must be between 1 and 32 bits.

5. Frequently Asked Questions (FAQ)

Q1: What's the maximum number of subnets possible?
A: The maximum is 2³¹ (over 2 billion) when changing from a /1 to a /32 mask, though practical limits are much lower.

Q2: Can I use this for IPv6?
A: No, this calculator is for IPv4 only. IPv6 subnetting follows different principles.

Q3: What if my new mask is smaller than the old mask?
A: The calculator will show no result as this represents supernetting (combining networks) rather than subnetting.

Q4: How does this relate to host addresses per subnet?
A: Hosts per subnet is calculated separately as 2^(32 - new mask) - 2 (for network and broadcast addresses).

Q5: What's the practical limit for subnet masks?
A: /30 is typically the smallest practical subnet (2 hosts), while /24 (256 hosts) is common for small networks.