IPv4 Network Range Calculator
Enter an IPv4 address and CIDR prefix (or subnet mask) to instantly calculate network details.
Why an IP network range calculator matters
An IP network range calculator helps you quickly find the exact boundaries of a subnet: network address, broadcast address, and usable host range. If you work with routers, firewalls, DHCP scopes, VLANs, cloud VPCs, or server deployments, this saves time and prevents costly addressing mistakes.
Instead of manually converting binary values and counting host bits, you can enter one address and prefix and get all the subnet math instantly. This is especially useful when troubleshooting overlapping networks or planning segmented infrastructure.
What this calculator gives you
- Network address: The first address in the subnet (identifies the subnet itself).
- Broadcast address: The last address in the subnet (used for broadcast traffic in traditional IPv4 networks).
- First and last host: The normal usable host range.
- Subnet mask and wildcard mask: Helpful for ACLs and routing rules.
- Total and usable hosts: Capacity planning made easy.
How CIDR works (quick refresher)
CIDR notation uses a slash, like /24. The number after the slash tells you how many bits are fixed for the network part. IPv4 has 32 total bits, so the remaining bits are for host addresses.
Simple examples
/24means 24 network bits and 8 host bits (256 total addresses)./16means 16 network bits and 16 host bits (65,536 total addresses)./30means very small subnet size (4 total addresses).
Manual subnet calculation steps (if you want to verify results)
1) Convert CIDR to subnet mask
Example: /27 becomes 255.255.255.224.
2) Find block size in the interesting octet
For 255.255.255.224, block size is 256 - 224 = 32. Subnets in the last octet start at 0, 32, 64, 96, 128, 160, 192, 224.
3) Locate the subnet containing your IP
If your IP is 192.168.10.77, it falls in the 64–95 block. So:
- Network:
192.168.10.64 - Broadcast:
192.168.10.95 - Host range:
192.168.10.65to192.168.10.94
Common subnet sizes cheat sheet
- /24 → 256 total, 254 usable
- /25 → 128 total, 126 usable
- /26 → 64 total, 62 usable
- /27 → 32 total, 30 usable
- /28 → 16 total, 14 usable
- /29 → 8 total, 6 usable
- /30 → 4 total, 2 usable
Practical use cases
Network design and VLAN planning
When splitting a LAN into smaller segments, you need exact subnet boundaries. This avoids overlap and makes route summarization cleaner.
Cloud networking
In AWS, Azure, and GCP, every VPC/VNet subnet must be defined in CIDR. A calculator helps you allocate ranges safely before deployment.
Firewall and ACL work
Knowing wildcard masks and exact subnet scopes is critical for writing accurate access rules.
Common mistakes to avoid
- Mixing up subnet mask and wildcard mask.
- Accidentally reusing overlapping subnets across sites or tunnels.
- Using network or broadcast addresses as host IPs in traditional subnetting.
- Forgetting that very small subnets (
/31,/32) behave differently.
Final thoughts
Subnetting gets easier with repetition—and with the right tool. Use this IP network range calculator whenever you assign addresses, build route tables, or troubleshoot connectivity. It gives you fast, consistent, and accurate subnet boundaries so you can focus on architecture and operations instead of manual bit math.