Networking / FREE BROWSER TOOL
IP in Subnet Checker
Test whether a specific IPv4 address belongs to a CIDR block and check the block boundaries without using an external lookup service.
✓ Free to use✓ Runs locally✓ No account needed
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Enter the values below to calculate or convert.
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Using the ip in subnet checker
Enter the network CIDR and the IPv4 address to check. A match means the address is inside the CIDR block, including its first and last addresses.
Real-world example
Example: 192.168.5.200 is inside 192.168.5.0/24, but not inside 192.168.5.0/25.
Good to know
CIDR membership is different from host usability. A network or broadcast address may be inside a block without being usable as a LAN host.
This tool is a planning aid, not a substitute for verifying values in vendor documentation or production configurations.