IPv4 Range Calculator
Enter any IPv4 address and CIDR prefix to instantly calculate the full subnet range, including network, broadcast, and usable host span.
Tip: Press Enter while focused on an input to calculate quickly.
Why a range of IP address calculator matters
When you configure networks, firewalls, VPNs, cloud instances, or on-prem servers, you constantly work with IP ranges. A range of IP address calculator saves time and reduces mistakes by translating a single IP address and CIDR prefix into concrete values you can use immediately: network address, broadcast address, first and last host, and total number of addresses.
Without a calculator, it’s easy to misread CIDR notation, especially when moving between /20, /23, or /27 networks. One small subnet mistake can break routing, block legitimate traffic, or expose systems unintentionally. A fast calculator helps teams stay accurate and consistent.
What this calculator gives you
This tool is focused on IPv4 subnet math and returns a practical breakdown:
- Subnet mask and wildcard mask for ACL and routing use cases.
- Network address and broadcast address.
- Usable host range (including correct handling of /31 and /32 edge cases).
- Total addresses and usable host count.
- Address class and basic address type classification (private/public/etc.).
How subnet range calculation works
1) Start with IP + prefix
Suppose you enter 192.168.10.42 with prefix /24. The /24 means the first 24 bits are the network portion and the last 8 bits are host bits.
2) Build the subnet mask
A /24 becomes 255.255.255.0. The mask is used in bitwise operations to identify network boundaries.
3) Find network and broadcast
- Network address = IP AND subnet mask
- Broadcast address = network + all host bits set to 1
For 192.168.10.42/24, that becomes:
- Network: 192.168.10.0
- Broadcast: 192.168.10.255
4) Determine usable host range
In traditional subnetting for prefixes up to /30, usable hosts are between network+1 and broadcast−1. For /31, both addresses are commonly used in point-to-point links. For /32, the range is a single host route.
CIDR quick reference
| CIDR | Subnet Mask | Total Addresses | Traditional Usable Hosts |
|---|---|---|---|
| /30 | 255.255.255.252 | 4 | 2 |
| /29 | 255.255.255.248 | 8 | 6 |
| /28 | 255.255.255.240 | 16 | 14 |
| /27 | 255.255.255.224 | 32 | 30 |
| /26 | 255.255.255.192 | 64 | 62 |
| /25 | 255.255.255.128 | 128 | 126 |
| /24 | 255.255.255.0 | 256 | 254 |
| /16 | 255.255.0.0 | 65,536 | 65,534 |
Common mistakes this tool helps prevent
- Mixing up network and host bits, especially in non-/24 subnets.
- Incorrect host range in firewall rules, resulting in blocked users or open access.
- Overlapping subnets in VPCs, VLANs, or site-to-site VPN designs.
- Wrong wildcard masks in ACL configurations.
Practical use cases
Firewall and ACL design
When defining allow/deny rules, you need exact start and end points. The calculator provides network and wildcard values directly, which reduces ACL syntax errors.
Cloud network planning
In AWS, Azure, and GCP, subnet planning is critical to avoid overlap across environments. Quick subnet math helps when carving VPC ranges into production, staging, and development blocks.
Troubleshooting connectivity
If two hosts cannot communicate, one of the fastest checks is whether both addresses belong to the same subnet range. This calculator makes that determination immediate.
Final note
This page focuses on IPv4. If you also work with IPv6, consider using a separate IPv6 calculator because address length, notation, and subnetting behavior are different. For day-to-day IPv4 operations, though, a reliable range of IP address calculator is one of the most useful tools you can keep in your networking toolkit.