Does this look up geolocation online?

No, it validates and formats offline; no requests leave your browser.

Are IPv6 addresses supported?

Yes, including compressed notation and CIDR prefixes.

What counts as reserved?

Loopback, link-local, private and documentation ranges are flagged.

Is my data uploaded to a server?

No. This tool runs entirely in your browser using standard web APIs, so your input never leaves your device and nothing is logged or stored on our servers.

Does it work offline and on mobile?

Yes. Once the page has loaded it keeps working without a network connection, and the layout is responsive so it stays usable on phones and tablets.

IP & CIDR List Validator

Validate and normalise lists of IPv4, IPv6 and CIDR entries offline.

Support

Works Offline

Privacy First

No Login

No API

IP / CIDR list

Validation results — 4 valid, 2 invalid, of 6 total

Input	Type	Normalized / note
192.168.1.1	IPv4	192.168.1.1
10.0.0.0/8	CIDR (IPv4)	10.0.0.0/8
2001:db8::1	IPv6	2001:db8::1
::1/128	CIDR (IPv6)	::1/128
999.1.1.1	Invalid	not a valid IP or CIDR
not-an-ip	Invalid	not a valid IP or CIDR

About the IP & CIDR List Validator

Paste a list of IP addresses and CIDR blocks to validate each entry, normalise its format, flag private or reserved ranges and export a clean list.

Examples

Example

192.168.001.1/24

Output

192.168.1.0/24 (private)

Keyboard shortcuts

Copy the main outputCtrl / ⌘ + Shift + C
Download the resultCtrl / ⌘ + S
Share this toolCtrl / ⌘ + Shift + S
Reset the inputsAlt + R
Open the tool search paletteCtrl / ⌘ + K

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Frequently asked questions

Version 1.0.0 · Updated 2026-08-09 · Runs entirely in your browser