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developer validator

IP in CIDR Checker

Check if an IPv4/IPv6 address is inside a CIDR block, client-side.

Results

Paste input and validate locally.
Status
Ready when you validate.
Details
Ready when you validate.
Inside?
Ready when you validate.
Family
Ready when you validate.
Range start
Ready when you validate.
Range end
Ready when you validate.

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

Inside

  • IP: 192.168.1.10, CIDR: 192.168.1.0/24 -> inside

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.