IP Address Validator
Validate IPv4 and IPv6 addresses and get network info.
Examples
How to use IP Address Validator
Enter Your IP Address
Click the input field labeled 'Enter IP Address' and type your IPv4 address (e.g., 192.168.1.1) or IPv6 address (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334). Paste from clipboard or type manually.
Click the Validate Button
Press the blue 'Validate IP' button below the input field. The tool processes your entry instantly without requiring any registration or account creation.
Review Network Information
View results in the 'Validation Results' panel showing IP validity status, IP type (public/private), CIDR notation, subnet mask, network range, and geolocation data. Copy any result using the copy icon next to each field.
Validate Additional Addresses
Clear the input field using the 'Clear' button and repeat steps 1-2 to validate more IP addresses. All validations are performed locally in your browser with no data stored.
Related Tools
IP address validator online: check IPv4 and IPv6 format and type
IP address validator online: check IPv4 and IPv6 format and type
Validate any IP address format and classify it as public, private, loopback, or reserved, ToolHQ's IP address validator checks both IPv4 and IPv6. Validated in your browser, no IP address is sent to any server.
An IP address validator checks whether a string is a properly formatted IPv4 or IPv6 address and identifies what type of address it is. Beyond basic format checking, it tells you whether an address is routable on the public internet, falls in a private network range, or is a reserved or loopback address, information that matters for networking, security configuration, and application development.
Validating addresses in your browser, rather than sending them to a server, is important when you are checking internal network addresses. A tool that sends your private IP ranges to a third-party server is a minor but unnecessary risk.
Key takeaways
- ToolHQ validates both IPv4 (e.g., 192.168.1.1) and IPv6 (e.g.,::1) formats
- IPv4 private ranges: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16 (RFC 1918)
- IPv4 loopback: 127.0.0.1; IPv6 loopback:::1
- The tool shows the address type: public, private, loopback, link-local, or reserved
- Validated in your browser, no IP address is sent to any server
How IPv4 and IPv6 addresses work
IPv4 addresses are 32-bit numbers written as four decimal octets separated by dots: 192.168.1.1. Each octet ranges from 0 to 255. The total address space is about 4.3 billion addresses, a number that proved insufficient as the internet grew, which is why IPv6 was developed.
RFC 791 defines the IPv4 protocol. A valid IPv4 address has exactly four octets, each between 0 and 255, separated by dots. Common invalid forms include octets above 255 (192.168.1.999), too few or too many octets (192.168.1), or non-numeric characters.
IPv6 addresses are 128-bit numbers written as eight groups of four hexadecimal digits separated by colons: 2001:0db8:85a3:0000:0000:8a2e:0370:7334. RFC 4291 defines the addressing architecture. IPv6 allows compression: consecutive groups of all zeros can be replaced with :: (once per address), so 2001:0db8:0000:0000:0000:0000:0000:0001 becomes 2001:db8::1. Leading zeros in each group can also be dropped.
The Wikipedia article on IP addresses covers both versions in detail, including the history of IPv4 exhaustion and the IPv6 transition.
IPv4 address types and their ranges
Not all IPv4 addresses are equal. The type of an address determines where it is routable and how it can be used.
| Address type | Range | Description |
|---|---|---|
| Private (RFC 1918) | 10.0.0.0/8 | Class A private range, home and office networks |
| Private (RFC 1918) | 172.16.0.0/12 | Class B private range, covers 172.16.0.0–172.31.255.255 |
| Private (RFC 1918) | 192.168.0.0/16 | Class C private range, most home routers use this |
| Loopback | 127.0.0.0/8 | Local host, 127.0.0.1 is standard localhost |
| Link-local | 169.254.0.0/16 | Self-assigned when DHCP fails (APIPA) |
| Multicast | 224.0.0.0/4 | Routing to multiple receivers simultaneously |
| Broadcast | 255.255.255.255 | Broadcast to all hosts on local network |
| Public | Everything else | Routable on the public internet |
Private addresses (RFC 1918) are not routed on the public internet. Devices on private networks reach the internet through NAT (Network Address Translation) on a router. This is why your home router has a public IP on its WAN port and assigns private addresses (like 192.168.1.x) to your devices.
IPv6 special addresses
IPv6 has its own set of reserved and special-purpose addresses:
| Address type | Range | Description |
|---|---|---|
| Loopback | ::1 | IPv6 equivalent of 127.0.0.1 |
| Unspecified | :: | Used when a host has no address yet |
| Link-local | fe80::/10 | On-link only, not routed beyond local segment |
| Unique local | fc00::/7 | IPv6 equivalent of RFC 1918 private ranges |
| Multicast | ff00::/8 | Group communications |
| Global unicast | 2000::/3 | Publicly routable, most internet IPv6 traffic |
When IP address validation matters
Form and API input validation: Any web application that accepts IP addresses as input (firewall configuration, server access control, VPN whitelist management) needs to validate that what the user entered is actually a valid IP address before storing or using it.
Configuration file review: When auditing server configs, .htaccess files, or application settings, validating IP addresses before they go live prevents outages from misconfigured allow/deny rules.
Scripting and automation: When processing log files or network data, validating IP addresses ensures you are working with legitimate values before passing them to other functions.
Security research: Identifying whether an IP address is from a private, public, or reserved range helps classify traffic and detect spoofed or unexpected addresses in logs.
Debugging network issues: Quickly checking whether an address falls in the correct private range helps diagnose why a device cannot reach the network (wrong subnet, address mismatch, gateway issues).
Kaito, a junior network administrator, was auditing the firewall rules for his company's cloud server. The rules file contained dozens of IP addresses and CIDR blocks that had been added over several years by different engineers. Some addresses looked suspicious. He pasted each IP into ToolHQ's validator and immediately saw which ones were valid public addresses, which were private ranges (which should not appear in cloud server firewall rules), and which were simply invalid. He found three entries that were malformed and removed them from the rules file.
Validate any IP address now, free, browser-based, no data sent
How to use ToolHQ's IP address validator
Open the tool. Go to https://www.toolhq.app/tools/ip-address-validator.
Enter the IP address. Type or paste an IPv4 or IPv6 address. The tool auto-detects the version.
Read the results. The validator shows:
- Whether the address is valid or invalid (and why, if invalid)
- The IP version (IPv4 or IPv6)
- The address type (public, private, loopback, link-local, multicast, reserved)
- The binary representation of the address
- For IPv4: the address class (A, B, C, D, or E)
- Use the result. For valid addresses, the type classification tells you where the address can be used. For invalid addresses, the error message tells you exactly why it failed.
The validator runs entirely in your browser, no IP address is sent to any server. This matters when you are validating internal network addresses that you would not want logged by a third-party service.
IPv4 vs. IPv6 validation: what changes
Both protocols require accurate formatting, but the rules differ.
IPv4 validation checks:
- Exactly four octets separated by dots
- Each octet is 0 to 255 (decimal)
- No leading zeros that would cause ambiguity (010 vs 10)
- No extra characters or spaces
IPv6 validation checks:
- Up to eight groups of four hex digits separated by colons
- Valid hex characters only (0-9, a-f, A-F)
- At most one
::compression per address - Compressed form expands to exactly 128 bits
- Optional embedded IPv4 notation (e.g.,
::ffff:192.168.1.1)
For related networking tools, ToolHQ's what is my IP shows your current public IP address, DNS lookup resolves domain names to IP addresses, and IP geolocation lookup identifies the geographic location associated with a public IP.
Sofia, a developer writing a registration form for a B2B SaaS platform, needed to validate IP addresses submitted through an admin API that allowed customers to whitelist their office IP ranges. She tested her validation regex against ToolHQ's validator, checking edge cases like 0.0.0.0, 255.255.255.255, 192.168.1.256 (invalid), and ::1. The validator confirmed which addresses her regex accepted or rejected, revealing that her pattern was incorrectly accepting some IPv4 addresses with leading zeros. She fixed the regex before the feature shipped.
Frequently asked questions
What is the difference between a private and public IP address?
Private IP addresses (defined in RFC 1918) are not routed on the public internet, they exist only within local networks. Public IP addresses are globally routable. Home devices typically have private addresses (192.168.x.x) while your router has a public address from your ISP.
Why does my device show 127.0.0.1?
127.0.0.1 is the loopback address, it always refers to the local machine. When a program "connects to itself," it uses 127.0.0.1 (or localhost, which resolves to 127.0.0.1). The entire 127.0.0.0/8 range is reserved for loopback.
What does::1 mean in IPv6?::1 is the IPv6 loopback address, equivalent to 127.0.0.1 in IPv4. It always refers to the local machine. The full form is 0000:0000:0000:0000:0000:0000:0000:0001, compressed to::1.
What is 169.254.x.x and why do devices get this address?
The 169.254.0.0/16 range (APIPA, Automatic Private IP Addressing) is self-assigned by Windows and macOS when a device cannot get an address from DHCP. If you see a 169.254.x.x address, it usually means your DHCP server is unreachable.
Can I validate CIDR notation like 192.168.1.0/24?
CIDR notation adds a prefix length to an IP address. Basic IP validation focuses on the address portion. For full CIDR validation, you need a subnet calculator that checks both the IP portion and the prefix length (0-32 for IPv4, 0-128 for IPv6).
The short version
IP address validation checks that an address is properly formatted and identifies its type, public, private, loopback, link-local, or reserved. Both IPv4 and IPv6 have specific formatting rules and reserved ranges that determine where an address can be used.
ToolHQ's validator handles both protocols, shows the binary representation, classifies the address type, and runs entirely in your browser. No IP addresses are sent to any server.
For related tools, check your current public IP with what is my IP or resolve domain names with the DNS lookup tool.
Validate any IP address free, browser-based, instant