CIDR Calculator
CIDR Calculator
Calculate IPv4 subnet details from CIDR notation: network address, broadcast, host range, subnet mask, wildcard mask, host count, and binary representation. Subnet splitter, VLSM, IPv6 support, and a CIDR aggregation/overlap checker.
Enter a CIDR address to inspect the subnet
Calculate IPv4/IPv6 subnet details, split a CIDR block into equal subnets, plan VLSM allocations, aggregate/check overlap across a list of CIDR blocks, or simulate a router's longest-prefix-match lookup against a routing table.
CIDR Calculator
Calculate IPv4 subnet details from CIDR notation: network address, broadcast, host range, subnet mask, wildcard mask, host count, and binary representation. Subnet splitter, VLSM, IPv6 support, and a CIDR aggregation/overlap checker.
Common uses
- Calculate the host range for 10.0.0.0/16
- Split 192.168.0.0/24 into 4 equal subnets
- Check a list of CIDR blocks for overlaps
- Summarize multiple CIDR blocks into the fewest supernets
Also searched as
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- how many hosts in a /24
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- vlsm calculator
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- cidr to netmask and wildcard mask
- route summarization calculator
- longest prefix match route table lookup
Frequently asked questions
How do I calculate the host range for a CIDR block?
Enter the CIDR, such as 10.0.0.0/16, in the Calculator tab to get network, broadcast, host range, subnet and wildcard masks, host count and binary form.
How do I split a network into subnets?
Use the Subnet Splitter for equal subnets or the VLSM tab for different-sized subnets.
Can I find overlapping CIDR ranges?
Yes, the Aggregate & Overlap tab checks a list for overlaps and summarizes blocks into fewer supernets.
What is the Route Table (LPM) tab?
It performs longest-prefix-match lookups against a list of routes.
Is my data uploaded to a server?
No. This tool runs entirely in your browser — your input is processed locally on your device and is never uploaded or stored on a server.