Subnet Planning for Network Admins

Plan IP allocation, calculate usable hosts, and size subnets for your network.

Nid oes angen mewngofnodi

IPv4 address

Prefix

/0/8/16/24/32

254

Usable hosts

256

Total addresses

Network address192.168.1.0/24

Usable host range192.168.1.1 – 192.168.1.254

Broadcast address192.168.1.255

Subnet mask255.255.255.0

Wildcard mask0.0.0.255

Mask (binary)11111111.11111111.11111111.00000000

IP classC

Address typePrivate (RFC 1918)

IPv4 subnetting reference. /31 and /32 are handled per RFC 3021 (point-to-point and single-host). All math runs locally in your browser.

Network Admin tips

🖧

Before deploying a VLAN, calculate the usable host count to make sure the subnet fits your device count plus growth headroom.

💡

Remember network + broadcast addresses are reserved — a /24 gives 254 usable hosts, not 256.

🎯

Use the binary mask view to teach or double-check VLSM (variable-length subnet masking) boundaries.

Sut Mae'n Gweithio

Ewch i mewn

Enter your data into the tool above. Everything stays local to your browser.

Proses

The tool processes your data instantly in your browser using JavaScript. No server, no waiting.

Lawrlwythwch

Get your result instantly. Nothing is stored after you leave the page — complete privacy.

Pam defnyddio ein un ni?

✓Hollol rhad ac am ddim - dim costau cudd, byth

✓Nid oes angen cyfrif, e-bost na mewngofnodi

✓Nid yw ffeiliau byth yn gadael eich dyfais

✓Dim cyfyngiadau maint ffeil o gwbl

✓Dim dyfrnodau ar unrhyw allbwn

Also check out…

🎓

Subnetting Practice for IT Students

Check your subnetting homework and CCNA practice p

🏠

Home Lab & Self-Hosting Subnets

Plan IP ranges for your home network, VLANs, Docke

☁️

Plan Cloud VPC CIDR Blocks

Size AWS/GCP/Azure VPC and subnet CIDR ranges befo

🛡️

CIDR Ranges for Firewall Rules

Convert IP ranges to CIDR notation for firewall al

Cwestiynau Cyffredin

Back to Subnet / CIDR Calculator