How to use it
- Choose the Kind of identifier and how many you need under How many.
- For a nanoid, set its Length and the characters of its Alphabet.
- Copy an ID from Generated IDs. Each row gives the time the ID holds, or a dash for a nanoid.
- Paste a ULID or a UUID version 7 into Read the time of to read the time it holds.
Three kinds of identifier
A ULID (ulid/spec) is 128 bits: 48 bits of Unix time in milliseconds, then 80 random bits, written as 26 characters of Crockford's base32. A UUID version 7 (RFC 9562, section 5.7) also starts with a 48-bit millisecond time, in the 8-4-4-4-12 form of a UUID. A nanoid is a random string of the length and alphabet you choose, and it holds no time.
- ULID: 26 characters, for example 01ARZ3NDEKTSV4RRFFQ69G5FAV
- UUID version 7: 36 characters, for example 017f22e2-79b0-7cc3-98c4-dc0c0c07398f
- Nanoid: any length and any alphabet, with no time
Order when IDs are made together
IDs made in one go share one millisecond. A ULID then counts its random part up by one from the previous ID, and a UUID version 7 counts a 12-bit counter, so the IDs sort in the order they were made (ulid/spec, Monotonicity; RFC 9562, section 6.2). Within one millisecond, a nanoid is not sorted: each one is drawn afresh.
The random values come from crypto.getRandomValues, the browser's own source of random bytes. A nanoid draws each character without bias, by skipping the byte values that would favour some characters.
Worked example: reading the time of a ULID
Pasting 01ARZ3NDEKTSV4RRFFQ69G5FAV, the example ULID of the specification, gives this result: The time is July 30, 2016 at 11:54:10 PM UTC, which is 1,469,922,850,259 milliseconds after 1 January 1970.
The first ten characters, 01ARZ3NDEK, hold the time. The last sixteen hold 80 random bits, so the ID sorts by its time as plain text.
Frequently asked questions
Is a ULID the same as a UUID?
It has 128 bits like a UUID, but it is written in 26 characters of Crockford base32 and it is not a UUID format. UUID version 7 is the RFC 9562 form that also starts with a time, and this page makes both.
Can I use these IDs as passwords or session tokens?
No. They are made to be unique and sortable, not to be secret. IDs made together share a time and count up, so the next one can be guessed. Use the password generator or a cryptographic token for secrets.
What is a nanoid-style ID?
A random string drawn from the alphabet you choose, with the length you choose. A 21-character ID from the 64 URL-safe characters carries about 126 bits of randomness, which is the default this page uses.
Why does a row show a dash instead of a time?
A nanoid is random from start to end and holds no time, so there is nothing to read. Only ULIDs and UUIDs of version 7 carry a creation time.
Why can the time of a UUID not be read?
Only version 7 UUIDs hold a time. The page tells you the version of the UUID you pasted, and reads a version 7 UUID that follows RFC 9562.
Are my IDs or the text I paste sent anywhere?
No. The IDs are made in your browser from crypto.getRandomValues, and the text you paste is read only here. Nothing is uploaded or stored.
Sources
- ULID specification (ulid/spec on GitHub)
- RFC 9562: Universally Unique IDentifiers (UUIDs), version 7
- Crockford's Base32 encoding
- W3C Web Cryptography API: getRandomValues
Figures and text last checked on Tuesday, November 10, 2026.