Calculator Inputs
Example Data Table
| IPv4 Address | CIDR | Subnet Mask | Network Address | Usable Range | Broadcast |
|---|---|---|---|---|---|
| 192.168.10.14 | /24 | 255.255.255.0 | 192.168.10.0 | 192.168.10.1 - 192.168.10.254 | 192.168.10.255 |
| 10.25.8.201 | /20 | 255.255.240.0 | 10.25.0.0 | 10.25.0.1 - 10.25.15.254 | 10.25.15.255 |
| 172.16.33.70 | /27 | 255.255.255.224 | 172.16.33.64 | 172.16.33.65 - 172.16.33.94 | 172.16.33.95 |
| 203.0.113.9 | /30 | 255.255.255.252 | 203.0.113.8 | 203.0.113.9 - 203.0.113.10 | 203.0.113.11 |
Formula Used
1. Network Address: Network = IP Address AND Subnet Mask.
2. Wildcard Mask: Wildcard = 255.255.255.255 minus Subnet Mask.
3. Broadcast Address: Broadcast = Network Address OR Wildcard Mask.
4. Total Addresses: Total = 2(32 - prefix).
5. Usable Hosts: Traditional usable hosts = Total minus 2 for prefixes up to /30.
6. Binary Conversion: Each octet becomes an 8-bit binary value for accurate mask validation.
How to Use This Calculator
- Enter the IPv4 address you want to inspect.
- Provide a CIDR prefix, subnet mask, or both matching values.
- Select your preferred host counting mode.
- Choose whether binary output should appear.
- Add an optional subnet label for documentation.
- Click Calculate Subnet Range to generate the result.
- Review network, broadcast, host range, and binary details.
- Use the CSV or PDF buttons to export the result.
Frequently Asked Questions
1. What does the subnet mask actually do?
The subnet mask separates network bits from host bits. It tells routers and hosts which portion identifies the subnet and which portion identifies individual devices inside that subnet.
2. Why are network and broadcast addresses special?
The network address identifies the subnet itself. The broadcast address targets every device inside that subnet. Most traditional host ranges exclude both addresses from normal device assignment.
3. What is the difference between CIDR and subnet mask?
CIDR is compact notation like /24. A subnet mask is dotted decimal notation like 255.255.255.0. Both represent the same boundary between network and host bits.
4. Why would I use modern host counting?
Modern host counting treats /31 point-to-point links as usable on both addresses. That follows RFC-aware practice and can conserve address space on routed network links.
5. Can this calculator validate incorrect masks?
Yes. It checks whether the subnet mask is contiguous. Masks like 255.0.255.0 are rejected because valid IPv4 masks must contain uninterrupted ones followed by zeros.
6. Why are binary details useful?
Binary views help you verify bit boundaries, borrowed bits, and host capacity. They also make it easier to troubleshoot unexpected overlaps or incorrect planning assumptions.
7. Can I use this for private and public networks?
Yes. The calculator works with any valid IPv4 address. It also classifies the address scope, helping you identify whether the input belongs to a private, public, or special range.
8. When should I export results?
Export results when documenting VLAN plans, firewall rules, branch addressing, migration sheets, or audit evidence. CSV is convenient for spreadsheets, while PDF works well for reports.