What /24 means
The prefix tells how many bits belong to the network. /24 leaves 8 host bits, so the block has 256 total IPv4 addresses.
Learning
Learn CIDR for real cloud design.
Plain-language subnetting lessons for students, cloud certification learners, junior engineers, and teams planning VPC or VNet address spaces.
Learning path
Start with the concepts that show up in every cloud network.
The goal is not only to calculate an answer. CIDRHub explains why the answer matters when you design private ranges, split subnets, connect networks, or deploy Kubernetes clusters.
Usable address count
Most IPv4 subnets reserve the first address as the network address and the last address as broadcast, leaving total minus two usable hosts.
Growth planning
Pick blocks large enough for future zones, private endpoints, load balancers, NAT, and clusters without wasting an entire private range.
Overlapping CIDRs
Two connected networks with overlapping CIDRs cannot route cleanly. Check peering, VPN, transit, and on-premises ranges before launch.
Read the prefix
Understand how many bits belong to the network and how many remain for addresses.
Find the range
Identify the network address, broadcast address, and first or last usable host.
Split the block
Create smaller subnets for tiers, zones, environments, and cloud services.
Check overlap
Compare ranges before peering, VPN, transit, private endpoints, or cluster networking.
Practice
Use the calculator while you learn.
Enter a range such as 10.20.0.0/24, change the prefix, then split it into smaller blocks. The calculator keeps the math visible so subnetting becomes easier to apply.
Open Calculator
Subnet signals
Network blocks, host ranges, and cloud address spaces represented as connected data.