Three different jobs, one word
"Random" gets attached to a lot of very different tools, and it's easy to reach for whichever one is already open rather than the one actually built for the job. A random number generator, a random password generator, and a random string (or UUID) generator all produce unpredictable output, but they're tuned for three distinct audiences: a human picking a winner, a human logging into an account, and a machine that needs a unique identifier. Using the wrong one usually still "works" in a narrow sense — but it can quietly produce something weaker, harder to read, or wrong in shape for what you actually needed.
Try the random generator
Random numbers: for picks, samples, and games
A random number generator does exactly one thing: returns a number within a range you set, with no character-set rules or formatting attached. This is the right tool for picking a raffle or giveaway winner from a numbered list of entries, rolling a die for a game, randomly sampling a subset of rows from a spreadsheet for quality review, or settling something like "who goes first" without any of it needing to look a particular way afterward — it's just a number, meant to be read by a person and used once.
Random passwords: built for a human to type, briefly
A password generator produces a string built around specific rules — a chosen length, and a mix of character types (uppercase, lowercase, numbers, symbols) you can usually toggle on or off individually, often to match a particular website's password requirements. It's tuned for something a person will eventually type, paste into a password manager, or read off a screen to someone else, which is why length and character-set composition are configurable in the first place: a site limiting passwords to 16 characters with no symbols needs a different generated output than one with no such restrictions.
The generator matters less than the output's actual randomness — see Nonkera's password generator guide for what separates a genuinely secure generator from a weak one dressed up to look strong.
Generate a password
Random strings and UUIDs: built for machines, not memory
A UUID (universally unique identifier) generator produces a long, standardized string — like 550e8400-e29b-41d4-a716-446655440000 — specifically designed to be astronomically unlikely to collide with another one generated anywhere else, ever, without any central coordination between the systems generating them. Nobody memorizes a UUID or types it manually with any regularity; it exists to be assigned as a database primary key, a session token, a filename that needs to be guaranteed unique, or an API request ID that ties a specific request to its logs. Where a password generator is optimized for a human's login flow, a UUID generator is optimized for a machine's need for a unique, collision-resistant label.
Generate a UUID
How to choose in practice
The fastest way to pick the right one is to ask who — or what — actually uses the output. If a person will read it once and act on it (a winner, a dice roll, a sample), a number generator fits. If a person will type or store it as a credential, a password generator fits, since it's the one built with character-set rules tuned for login requirements. If a system will store it forever as a unique reference that a person never types by hand, a UUID or random string generator fits — using a password generator for that job produces something that technically works but wasn't designed for machine-to-machine use, and using a UUID as a password produces something needlessly long and awkward for a human to type.