Practical example
For 192.168.10.0/27, confirm the address range and reserve network, gateway, broadcast, and infrastructure addresses before assigning hosts.
IP Subnet Calculator
Options
Status
Idle
Subnet summary
IP class
Address type
Network address
Broadcast address
Subnet mask
Wildcard mask
First usable host
Last usable host
Total addresses
Usable hosts
Binary view
Binary IP
Binary subnet mask
What is an IP Subnet Calculator?
An IP Subnet Calculator helps you calculate the network details of an IPv4 address and CIDR block.
It is useful for networking, DevOps, server setup, firewall rules, cloud infrastructure, and troubleshooting address ranges.
How to use the IP Subnet Calculator
- Enter an IPv4 address and CIDR, such as 192.168.1.10/24.
- You can also fill the IP and CIDR fields separately.
- Click Calculate to see the network address, broadcast, subnet mask, and usable range.
- Copy the summary output if needed.
Tips
- A /24 network usually has 256 total addresses and 254 usable hosts.
- A /32 represents a single IPv4 address.
- A /31 is often used for point-to-point links.
- The wildcard mask is useful for ACL and router configurations.
Subnet planning checks
Avoid overlapping ranges
Check whether a planned subnet overlaps with VPN, office, VPC, Kubernetes, or database allowlist ranges before using it.
Size for growth
Leave enough usable hosts for future services, load balancers, NAT gateways, containers, and temporary environments.
Use narrow allowlists
For firewall and database access, prefer the smallest CIDR range that matches the real source addresses.
Document private ranges
Record why each private range exists so future network migrations do not accidentally reuse the same address space.
Related guides
Learn the workflow behind this tool and what to check next.
Networks
IP subnet basics for developers
A practical subnetting guide for reading CIDR notation, checking network ranges, planning private networks, and avoiding address conflicts.
Read guide
DNS and domains
How to troubleshoot DNS records for a domain
A practical DNS checklist for website hosting, email records, domain verification, nameserver changes, SSL certificates, and reverse DNS.
Read guide
Subnet checks before assigning or routing an IP range
Verify address family, prefix length, reserved addresses, and the platform's routing model before applying calculated boundaries.
Network boundaries
Confirm network, broadcast, first and last usable addresses, total size, and whether the environment reserves additional addresses.
Prefix interpretation
Keep CIDR prefix and subnet mask aligned and avoid applying IPv4 host assumptions directly to IPv6 networks.
Overlap detection
Compare proposed ranges with VPCs, VPNs, containers, offices, partner networks, and future expansion space.
Routing and access
Review route tables, gateways, NAT, firewalls, ACLs, and cloud-specific reservations before deployment.
A practical example, an edge case, and a maintainer note
Edge case
/31 point-to-point and /32 host routes do not follow the usual usable-host subtraction, and IPv6 has no broadcast address.
Maintainer note
I compare the calculated block with routing tables, DHCP pools, and cloud-provider reservations before deployment.
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IP Subnet Calculator FAQ
Can this tool calculate broadcast and subnet mask?
Yes. It calculates network address, broadcast address, subnet mask, wildcard mask, and host range.
Does it support IPv6?
This version focuses on IPv4 subnet calculations.
What is the difference between total and usable hosts?
Total addresses include network and broadcast addresses, while usable hosts usually exclude them in standard IPv4 subnets.
Is my IP stored?
No. Everything is processed in your browser.