IPv4 and IPv6 Converter
Paste one address and read back every form: dotted, integer, hex, binary, expanded, compressed and mapped.
This IPv4 and IPv6 converter takes one address and lines up every form next to each other, so a firewall ticket, a database row and a packet capture can finally agree they mean the same host. Paste dotted IPv4, a raw decimal integer, a 0x hex value, 32 bits of binary, or any IPv6 (mapped ones included) and auto detect figures out the rest, or pin the input mode by hand. For IPv4 you get the decimal integer, hexadecimal, binary octets, the PTR hint and the IPv4-mapped IPv6 spelling. For IPv6 you get compressed and expanded notation, the 16-bit groups, full hex, the decimal value, binary groups, the ip6.arpa name and an address-type label like RFC1918, link-local or unique local. It all runs in your browser and nothing you paste ever leaves the page.
100% in your browser. Nothing you type ever leaves this page.
Local IP format utility
One address, five costumes. I built this after a bad afternoon: a firewall ticket, a database row and a packet capture all swore they meant the same host, and I wanted proof before I touched a single rule. So. Paste dotted IPv4, a raw integer, a 0x hex value, 32 bits of binary, or any IPv6 (mapped ones too) and every form shows up next to each other.
This all runs in your browser. Nothing I show you ever leaves the page. One heads-up though: an IPv4-mapped IPv6 address is just a way of writing an IPv4 host down on paper. It doesn't conjure up a real IPv6 path to the thing.
Why IP address conversion matters
Nobody warns you about this part. One address wears a different face in every tool you open. The firewall hands you dotted IPv4. The app database tucked that exact same address away as a giant integer, because of course it did. Crack open a packet capture or some crusty old ACL example and suddenly it's binary or hex. Then IPv6 shows up and piles on its own mess: compressed forms, expanded groups, a reverse name so long it wraps three times. Converting is how you prove two systems mean the same host before you push a rule or sign off on an incident.
That's the whole job here. The friendly forms and the machine forms, sitting next to each other so you can eyeball them. Hand it an IPv4 address and you get back the decimal integer, the hex, the binary octets, the PTR hint, and its IPv4-mapped IPv6 spelling. Hand it IPv6 instead and you get compressed and expanded notation, the 16-bit groups, full hex, the decimal value, binary groups, a guess at what kind of address you're holding, plus the ip6.arpa reverse name.
IPv4 and IPv6 are not interchangeable
Both protocols chase the same goal, give every endpoint an address, yet they're built completely apart and sized nothing alike. IPv4 is 32 bits. IPv6 is 128. The mapped form trips people up constantly. Something like ::ffff:192.168.1.42 is genuinely handy when a piece of software wants to treat an IPv4 connection as if it were IPv6, and yeah, it'll show up in your logs looking like that. Still an IPv4 host though. It's wearing an IPv6 hat, nothing more. Seeing it does not mean one single packet can reach that box over native IPv6.
How to read the formats
- Dotted IPv4 is the four-octet spelling you stare at all day. No surprises.
- The integer and hex forms are what hides inside databases and APIs, the lower-level plumbing that frankly couldn't care less about human eyes.
- Binary is ugly to look at. But it's the one view that shows you exactly where the bits split, which honestly is gold when you're subnetting or double-checking a mask.
- Compressed IPv6 strips the leading zeros and collapses the longest run of zero groups, so you're not sitting there typing forever.
- Expanded IPv6 lays out all eight groups. That's the form I trust when I'm comparing two addresses character by character.
- The reverse DNS hint just builds the name a PTR lookup would go ask for. It's not a promise that anyone actually created that record.
Useful address-type clues
Changing the notation is only half of what I want from a converter. The other half is a fast gut-check on what I'm even holding. An RFC1918 IPv4 address is never reaching the open internet. Loopback and link-local stay home. IPv6 drags in its own crowd: loopback, link-local, unique local, multicast, the documentation range, global unicast, and the tool flags whichever one you've got. Sounds minor. That one little label has saved me from pasting a private address into a public firewall rule more than once, and from the cringey ticket reply that always follows.
Frequently asked questions
Why does IPv6 have several correct spellings?
The spec hands you two shortcuts. Drop the leading zeros inside any group. Squash one run of all-zero groups down to a double colon. So a long expanded address and a short compressed one can be the exact same 128 bits underneath. They just got dressed differently that morning.
Can I paste an IPv4 integer or hex value?
Go for it. Auto detect grabs plain decimal integers, and it grabs anything starting with 0x, no help needed. When a value is murky enough that even I would squint at it, just pin the input mode by hand and the guessing stops.
Does the reverse DNS hint query the DNS record?
No. I kept it that way on purpose. All it does is assemble the name a PTR lookup would go ask for. The moment you actually need to know whether that record exists and what it answers back, run a real reverse DNS lookup.
Can every IPv4 address be written as IPv6?
Yep, through the IPv4-mapped form like ::ffff:192.168.1.1. It exists so IPv6-only software can still cope with an incoming IPv4 connection. Do not read too much into it though. It is a way of writing the address down, not proof you have actually migrated a thing.
What does the integer form of an IP represent?
An IPv4 address is 32 bits. Which means underneath, it is really just one number sitting somewhere between 0 and 4294967295. Computers adore that. Trivial to store, trivial to do math on. The dotted version exists purely so we humans can read the thing without going cross-eyed.