Inside
- IP: 192.168.1.10, CIDR: 192.168.1.0/24 -> inside
developer validator
IP in CIDR Checker
Check if an IPv4/IPv6 address is inside a CIDR block, client-side.
Results
Processing…- Status
- Processing...
- Details
- Processing...
- Inside?
- Processing...
- Family
- Processing...
- Range start
- Processing...
- Range end
- Processing...
Rules & checks
Parses IPv4 and IPv6 addresses and CIDRs; requires the same family.
Computes the network range and tests membership.
Runs entirely in your browser/offline; no data leaves the page.
When to use it
- Check admin/IP allowlists or blocklists
- Validate support tickets and logs quickly
- Preflight firewall, security group, or WAF rules
Tips
- Keep IP and CIDR in the same protocol (v4 or v6)
- Pair with the CIDR to Range converter to inspect boundaries
Examples
Outside
- IP: 192.168.2.10, CIDR: 192.168.1.0/24 -> outside
IPv6
- IP: 2001:db8::1, CIDR: 2001:db8::/64 -> inside
FAQs
- Is anything uploaded?
- No. Checks run locally and clear on refresh.
- Do you expand the full list?
- No. We compute start/end and membership only for speed.
Related validators
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CIDR Validator
Validate IPv4/IPv6 CIDR blocks and view the normalized network address.
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CIDR to Range Converter
Convert IPv4/IPv6 CIDR blocks to explicit start/end ranges client-side.
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CIDR Overlap Checker
Check whether two IPv4/IPv6 CIDR blocks overlap—runs entirely client-side.
Membership check only; does not test reachability or routing.