Calculate IPv4 CIDR Ranges, Netmasks, Broadcast IPs & Usable Cloud Hosts

Q: Why does AWS reserve 5 IP addresses in every VPC subnet instead of 2?

In addition to the network (.0) and broadcast (.255) addresses, AWS reserves .1 for the VPC router, .2 for AWS DNS, and .3 for future use.

Enter any CIDR block (like 10.0.0.0/16 or 192.168.1.0/24) to inspect network address, broadcast IP, wildcard mask, binary netmask, and AWS VPC usable host counts.

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INPUT SOURCE 12 chars

10.24.0.0/22

LIVE PROCESSED OUTPUT UTF-8 • CLIENT-SIDE

Processing...

Ready • 100% local execution Server Cost: $0.00 • Latency: <5ms

How to Use the CIDR Subnet Calculator

STEP 01

Enter an IPv4 CIDR block (e.g., 10.24.0.0/22 or 192.168.10.0/24) into the input pane.
STEP 02

Toggle between Standard RFC host counts and Cloud VPC mode (AWS/GCP reserve 5 IPs per subnet).
STEP 03

Copy the calculated network summary, netmask, and usable host IP range.

Frequently Asked Questions (CIDR Subnet Calculator)

Why does AWS reserve 5 IP addresses in every VPC subnet instead of 2?

In addition to the network (.0) and broadcast (.255) addresses, AWS reserves .1 for the VPC router, .2 for AWS DNS, and .3 for future use.