Password Generator
Create a strong, random password. Nothing you generate here is sent anywhere or stored — it only exists in your browser.
Password Generator: How to Create Strong, Unbreakable Passwords in 2026
Quick summary: A password generator uses a cryptographically secure random number generator to build passwords that are long, unpredictable, and free of the human patterns hackers exploit — and current NIST guidance says length now matters more than complexity. Use a password generator to create a random string of at least 15 characters (or a random passphrase) for any account that isn’t protected by multi-factor authentication.
Weak, reused, or guessable passwords remain one of the leading causes of account takeovers and data breaches. A password generator solves this problem instantly by producing a truly random string of characters that no human — and no cracking tool — could reasonably predict. In this guide, we’ll explain exactly how a password generator works, the math (entropy) behind password strength, what security researchers and everyday users on Reddit actually recommend, and how to choose the right settings for your own accounts.
What Is a Password Generator?
A password generator is a tool that automatically creates a random password based on parameters you choose — length, character types, and whether to use words or random characters. Instead of you trying to invent a “clever” password (which humans are famously bad at), the generator pulls from a cryptographically secure random number generator (CSPRNG) to produce a string with no discernible pattern.
Most browsers now include a built-in CSPRNG through the Web Crypto API (crypto.getRandomValues()), which is why modern password generator tools — including built-in browser and password-manager generators — are considered trustworthy. Standard (non-cryptographic) random functions can be predicted or reverse-engineered, but CSPRNGs are specifically designed to resist this since predictable random functions are a security weakness that cryptographically secure generators are built to overcome.
Why You Need a Password Generator (Not Your Own Brain)
Humans are bad at randomness. When left to create our own passwords, we default to predictable patterns: a capital letter at the start, a number at the end, a special character tacked onto a word we already know. Security researchers have found that forced complexity requirements actually train people toward predictable behavior — capitalizing the first letter, adding a number at the end, or appending a symbol — patterns that password-cracking tools are specifically built to exploit.
That’s exactly why the newest guidance from the National Institute of Standards and Technology (NIST) has shifted its recommendations.
The 2025–2026 NIST Password Guidelines
NIST’s Special Publication 800-63B (Revision 4), finalized in 2025, changed the conversation around password security in a few important ways:
- Length beats complexity. NIST SP 800-63B requires verifiers to enforce a minimum of 15 characters when a password is the only authentication factor, and a minimum of 8 characters when it’s paired with a second factor like MFA.
- Composition rules are discouraged. NIST now explicitly prohibits mandatory composition rules — “at least one uppercase letter, one digit, one symbol” — because these rules produce predictable patterns that reduce real entropy.
- Passwords should be allowed up to 64 characters, and systems should accept spaces and Unicode characters. Employees and users should be able to create passwords as long as 64 characters, and length is described as the primary factor in password strength.
- No more forced periodic resets. NIST explicitly prohibits mandatory password expiration; a password should only be changed if it’s confirmed compromised or the user wants to change it, because mandatory rotation pushes users toward weaker, more predictable passwords.
Other agencies agree on the direction, if not the exact number. <cite index=”15-1″>The Cybersecurity and Infrastructure Security Agency (CISA) recommends passwords of at least 16 characters in its consumer guidance, and actively promotes multi-word passphrases as the easiest way to reach that length without sacrificing memorability.
How a Password Generator Works: The Formula Behind Password Strength
A password generator’s real value is measured in entropy — a mathematical measure of how unpredictable a password is, expressed in bits. The formula is:
Entropy (bits) = log2(R^L) = L × log2(R)
Where:
- R = the size of the character pool (e.g., 26 lowercase letters, 52 upper+lowercase, 94 for all printable ASCII characters)
- L = the length of the password
Worked example 1 — random characters: A 12-character password using all 94 printable ASCII characters has:
Entropy = 12 × log2(94) ≈ 12 × 6.55 ≈ 78.6 bits
Worked example 2 — a passphrase: A four-word passphrase drawn from a 20,000-word dictionary produces:
Entropy = log2(20,000^4) = 4 × log2(20,000) ≈ 4 × 14.29 ≈ 57.2 bits
This mirrors real-world tools: one open-source passphrase generator built on this exact method reports <cite index=”10-1″>an estimated password entropy of roughly 57.6 bits for its default four-word output, such as “CorrectHorseBatteryStaple7.” That reference is a nod to the famous XKCD comic that popularized the “multiple random words beat a single complex word” approach.
Worked example 3 — comparing length vs. complexity: A truly random 15-character password using only lowercase letters actually provides more entropy — and therefore better security — than an 8-character password built with forced uppercase, numbers, and symbols. This is the mathematical proof behind NIST’s length-over-complexity shift: doubling your character pool (say, from 26 to 94 options) adds only a few bits per character, but every additional character multiplies your total possibilities.
Types of Password Generators
1. Random Character Generators
These produce strings like T9!kd$4vXr2@Lp by pulling randomly from a character pool. They’re extremely high-entropy per character but harder to memorize — best used with a password manager.
2. Passphrase Generators
These string together multiple random dictionary words (e.g., granite-otter-lantern-cactus9). They’re easier for humans to remember and type, while still reaching strong entropy totals when enough words are used. A well-built passphrase generator is designed to be simple for the general public and adds a secondary source of entropy — like mouse or finger movement — on top of the browser’s built-in randomness, since a user can’t easily verify that the browser alone is behaving randomly.
3. Pattern-Based Generators
Newer tools let users define a memorable pattern (like capitalization or digit placement) that the generator fills with random values, then reports the resulting entropy back to the user so they can judge the trade-off between memorability and randomness.
Best Practices When Using a Password Generator
- Set the length to at least 15–16 characters for any account not protected by MFA, per current NIST and CISA guidance.
- Enable all character types (upper, lower, numbers, symbols) if you’re not using a password manager to store the result — but understand that length matters far more than variety.
- Avoid “excludes similar characters” only if you’re typing manually; if a password manager is autofilling it, ambiguous characters like
1,l, andIdon’t matter. - Never reuse a generated password across sites. A generator should be run fresh for every account.
- Pair it with multi-factor authentication (MFA). MFA requires users to verify their identity through two or more factors and significantly reduces the risk of unauthorized access even if a password is somehow compromised.
- Check new passwords against breach databases. Modern best practice screens generated (or chosen) passwords against lists of previously leaked credentials before allowing them to be set.
- Use a reputable password manager to store your output — generating a strong password is only half the job; you still need somewhere secure to keep it rather than reusing it from memory.
What People Are Asking (and Discussing on Reddit)
Across security-focused communities and “People Also Ask” boxes, a few questions come up again and again:
“Is it safe to use an online password generator?” Generally yes, as long as the tool runs the randomness generation locally in your browser (client-side) rather than sending your request to a server. Privacy-conscious generator projects are built explicitly around this idea — running as a single static file with no external servers involved, so the tool “doesn’t touch any other servers” once it loads. If you’re unsure, look for a generator that’s open-source or explicitly documents that generation happens in your browser.
“How long does a password need to be to be uncrackable?” There’s no single “uncrackable” length, but the consensus among practitioners has converged around 15–16 characters as the comfortable modern minimum, scaling up for higher-value accounts. Enterprise security teams commonly use a 14- to 16-character baseline, and both entropy math and real-world breach data point to 16+ characters as a comfortable target for accounts that matter — the debate is only about the exact floor, not the overall direction.
“Should I still add special characters if I use a long passphrase?” It won’t hurt, but it’s no longer the priority. Community discussion and official guidance both converge on the same point: extra length adds more real-world protection than swapping a letter for a symbol.
“Why did NIST stop requiring password complexity rules?” Because complexity rules backfired.NIST’s newer position frames mandatory complexity (special characters, numbers) as “out” and length as “in,” while regularly scheduled resets are also out in favor of resets only triggered by an actual security breach.
Frequently Asked Questions
Aim for at least 15 characters for any password acting as your sole authentication factor, and at least 8 characters (ideally more) when it’s backed by MFA — the exact minimums specified in current NIST guidance.
Yes, when they use enough random words. Four or more truly randomly selected dictionary words can reach 55–80+ bits of entropy, which is well within the range security professionals consider strong, especially when combined with MFA.
Not as a strict requirement anymore. Current guidance discourages mandatory composition rules because they create predictable patterns; length and true randomness matter more.
Only when there’s evidence the password has been exposed in a breach — not on a fixed schedule. Frequent forced changes tend to push people toward weaker, more predictable passwords.
Yes. Human-created passwords tend to follow guessable patterns (names, dates, keyboard walks, word-plus-number combos), while a generator draws from a cryptographically secure random pool with no underlying pattern for an attacker to exploit.
Generally yes — modern browsers use the Web Crypto API’s crypto.getRandomValues() method, which is a cryptographically secure random number generator suitable for this purpose.
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Once your accounts and finances are secured, you may find these related tools useful:
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Conclusion
A password generator remains the single easiest way to protect your online accounts, turning a task humans are bad at (inventing true randomness) into something a computer does instantly and reliably. Whether you choose a random-character password or a multi-word passphrase, aim for at least 15 characters, avoid reuse, and pair every generated password with multi-factor authentication wherever it’s offered. Run your next password through a password generator before your next account signup — it takes seconds and closes one of the most common doors attackers walk through.