Random Password Generator
This tool can generate secure, strong, random passwords. To ensure security, the password is generated completely on the webpage without being sent across the Internet.
A password is typically a string of characters that may include letters, numbers, and symbols that can be used to access something, typically an account, and prevent others from accessing it. In today's Internet age, it is likely that most people have experience with having a password for some kind of account. As such, it is important to understand how to construct a strong password (or use a password generator) as well as to understand how to take measures to safeguard the password.
Password strength
Password strength is a measure of how effective a password is against being guessed or against brute-force attacks. Although it varies, usually, password strength is an estimate of how many trials would be required on average for someone to successfully guess the password. This is affected by the length, complexity, and unpredictability of the password. For example, if a password involves a person's name, birthday, or other personal information that typically would not be very difficult to find out, the password would likely make for a weak password.
Aside from the actual password, proper security controls play a significant role in reducing the risk of a security breach. Security controls include safeguards that are in place to detect, avoid, or minimize security risks. This includes controls such as two-step authentication for your password, or locking the account for a period of time after a given number of failed attempts.
How to create a secure password
Creating a secure password can be achieved by following certain rules that are designed to increase password security. This largely involves constructing a strong password, but includes other aspects such as changing a password periodically, as well as being aware of, and avoiding the use of common passwords (password, 123456, qwert...). Below are some rules that can be used for creating a strong password:
- Include lower-case letter(s) [a-z]
- Include upper-case letter(s) [A-Z]
- Include numbers [0-9]
- Include symbols [!@#$%^&*()...]
- Exclude words involving the user's personal information
- Exclude words found in a password blacklist – there are password blacklists that can be found on the Internet, or it is possible that a company / other institution may have their own password blacklists
- Exclude company/institution name, as well as abbreviations of the name
- Exclude passwords that match common formats such as calendar dates, license plate numbers, phone numbers, or other common number formats
Also, many password policies typically include a minimum password length because generally, the longer a password, and the larger the variety of character types, the more secure the password.
The random password generator on this website provides the user with the option to exclude ambiguous characters. This includes characters like the letters "L" and "I" which may be difficult to distinguish on a computer. This is particularly relevant when using a random password generator. An upper-case "i" can be difficult to distinguish from a lower-case "L" or the number 1 in some cases. Confusion arising from ambiguous characters could potentially lock the user out of their own account. Note however, that excluding characters generally lowers the potential strength of a password.
Password entropy
The password generator also determines the password entropy, measured in bits. The higher the entropy, the more difficult it will be for the password to be guessed. In the context of a brute force search (where every possibility is tested), a password entropy of 100 bits would require 2100 attempts for all possibilities to be exhausted. On average however, about half of these possibilities would need to be exhausted before the correct one is found in a brute force search.
How to protect your password
Protecting your password is as important as coming up with a strong password. Below are some suggested measures you can take to help protect your password. There are likely other measures a person can take, but the below are just some guidelines that may help:
- Don't share your password with other people – Ideally, the user should be the only person who knows their password. For example, even if you trust the person that you share your password with, and even if that person has no malicious intent, they may be less careful about safeguarding your password than you would be. The more people who know your password, the more potential for your information to be stolen by someone else.
- Don't use the same password across different websites and accounts – Although it may be more convenient to use the same password across different websites and accounts, it is not advisable. Having the same password for all your accounts, no matter how strong the password, may mean that a security breach on any single account compromises the safety of all of your accounts. Using a password manager can help you manage your passwords and accounts, and increase safety by allowing you to more easily use different passwords for different accounts. There are a number of different password managers that you can explore to find one that best suits your needs.
- Change your passwords regularly – This is another measure you can take that is also inconvenient, but theoretically, can help with keeping your accounts secure. This helps in cases where someone may know your password, and may access them, but may not immediately try to do something harmful. In these cases, changing your password would limit the period of time over which they have access to your account, assuming that they cannot determine the new password. In cases where you have saved your password on an old device you may have sold or thrown away, changing your password would disable a person from using a saved password.
- Never save your passwords to public devices – Ideally, try not to save passwords at all to reduce the risk of people gaining unwanted access to your accounts. In a similar vein, be careful of accessing sensitive accounts on unsecured public networks.
- Don't keep obvious lists of your passwords that someone may be able to access, physical, or electronic – For example, a sticky note on your desk with accounts and their passwords, a word document on your desktop named "passwords" that contains information for all your accounts, or a note on your cellphone could open you up to unnecessary risk of password loss. As mentioned above, consider using a password manager instead. Phones, notebooks, etc., can be lost or stolen. Ideally, a person should use a password manager or be able to remember their passwords for various accounts based on the specific account.
Generate Passwords That Actually Survive Real-World Attacks
A 12-character password with mixed case and numbers cracks in hours on consumer hardware. Bump it to 16 characters with symbols, and the same attack stretches past a human lifetime. Length beats complexity. Every time.
Why Your “Strong” Password Probably Isn’t
Most people overestimate password strength because they judge by
feel, not math. The entropy of a password—its true randomness measured
in bits—depends on two variables: the size of the character pool and the
length of the string. A password like Tr0ub4dor&3 looks
complex. It isn’t. It follows predictable patterns: dictionary word,
leetspeak substitutions, appended symbol and number. Attack dictionaries
include these transformations.
The crack time difference between pattern-based and truly random generation is staggering. A 12-character fully random password from 95 printable ASCII characters yields ~78.8 bits of entropy. That same length with a common word-pattern drops below 40 bits. At 40 bits, a determined attacker with modest GPU resources needs days, not eons.
The hidden variable most users miss: password managers change the entire equation. When you don’t need to memorize a password, length becomes free. You can generate 20-, 30-, 50-character strings because you’ll never type them. The calculator’s real value emerges here—not in helping you craft memorable passwords, but in quantifying what “unbreakable” actually costs in character count.
Here’s the asymmetry that matters: adding one character to a random password multiplies crack time by the pool size. Going from 15 to 16 characters at 95 options per position increases combinations by 95x. Adding another symbol type—say, moving from 62 to 95 characters—only multiplies by 1.5x per position. Length dominates. Complexity helps at the margin.
| Password Construction | Pool Size | Length | Entropy (bits) | Relative Strength |
|---|---|---|---|---|
| Lowercase only | 26 | 12 | 56.4 | Baseline |
| Mixed case + numbers | 62 | 12 | 71.5 | 36,000x stronger |
| Full ASCII | 95 | 12 | 78.8 | 2.9 million x stronger |
| Full ASCII | 95 | 16 | 105.1 | 2.7 billion billion x stronger |
| Full ASCII | 95 | 20 | 131.4 | Effectively unbreakable |
| Diceware (7,776-word list) | 7,776 | 6 words | 77.5 | Comparable to 12-char ASCII |
Entropy calculated as log₂(pool^length). Diceware uses word count, not character count.
The Diceware row reveals a critical trade-off. Six random words from a 7,776-word list generates comparable entropy to 12-character ASCII, but with superior memorability. If you must remember a password—say, your master password for a password manager—Diceware beats constructed complexity. For stored credentials, maximize length without regard to memorability.
How Attackers Actually Break Passwords
Understanding threat models transforms how you use a generator. Not all attacks brute-force every possible combination. The most common and dangerous attacks exploit human behavior patterns.
Dictionary attacks run ordered word lists with
frequency weighting. “Password” appears before “xylophone.” Combined
with rule-based mutations—appending years, substituting
@ for a, capitalizing first letters—these
attacks crack most human-created passwords without touching brute force.
Hashcat, the standard password recovery tool, ships with thousands of
mutation rules derived from leaked password analysis.
Credential stuffing requires no cracking at all. Attackers take username/password pairs from breached sites and automate login attempts across hundreds of services. Your 24-character random password fails instantly if you reuse it and any site in your rotation leaks data.
Brute force becomes relevant only for offline attacks against stolen password hashes. Here, speed matters enormously. A single modern GPU can test billions of hashes per second for fast algorithms like MD5 or SHA-1. Slower key derivation functions—bcrypt, Argon2, PBKDF2—intentionally consume compute to slow attacks, but the underlying password entropy remains your ultimate defense.
The calculator’s output assumes pure brute force against random generation. Real attacks are faster against human-chosen passwords, slower against stored hashes with proper key stretching. Treat the calculator’s “crack time” as an upper bound for random passwords, a fantasy for patterned ones.
Practical implication: Generate passwords at 80+ bits of entropy minimum for any account you wouldn’t want compromised. For high-value targets—email (password reset vector), financial accounts, password manager master passwords—target 100+ bits. The cost is zero if you use a manager.
Using the Generator: Configuration That Matches Your Threat Model
The calculator presents options: length, character types, exclusion of ambiguous characters. Most users select all options at maximum. This wastes entropy in some contexts and creates usability failures in others.
Length first. Set this before anything else. For memorized passwords, 6 Diceware words or 20+ characters of random ASCII. For managed passwords, 32+ characters unless the target service imposes arbitrary limits—which many do, often silently truncating.
Character pool selection involves real trade-offs:
| Scenario | Recommended Pool | Rationale |
|---|---|---|
| Password manager storage | Full ASCII (95 chars) | Maximum entropy, no typing needed |
| WiFi WPA3 passphrase | Full ASCII, 20+ chars | Offline attack resistance critical |
| Workstation login (typed often) | Alphanumeric + limited symbols | Reduces typos, still strong at 16+ chars |
| Legacy system with unknown constraints | Alphanumeric only | Prevents silent truncation or rejection |
| Shared verbally or written by hand | Diceware words | Error-resistant, high memorability |
The “exclude ambiguous characters” option—removing
0/O,
1/l/I, etc.—exists because humans
read and type these passwords. For machine-to-machine use, this option
reduces pool size and entropy for no benefit. Enable it only when manual
transcription is probable.
Hypothetical example: You’re configuring a generator for a new password manager vault. Sample inputs: 24 characters, full ASCII including spaces, no exclusion. The calculator reports ~157 bits of entropy. Crack time against a single GPU at 10 billion guesses/second for a fast hash: ~10²⁷ years. Against a slow hash at 10,000 guesses/second: still ~10²³ years. The universe’s age is ~1.4×10¹⁰ years. This password does not fail to brute force. It fails if you reuse it, store it insecurely, or fall for phishing.
Beyond Generation: Storage, Rotation, and Recovery
A password generator produces secrets. It does not protect them. The chain of custody matters as much as the secret’s strength.
Password managers are the only viable storage for non-memorized credentials. Browser-saved passwords lack encryption controls. Spreadsheets and text files are breach amplifiers. Dedicated managers—1Password, Bitwarden, KeePass, Proton Pass—encrypt vaults with your master password and support hardware security keys for second-factor authentication.
Rotation policies have shifted. NIST SP 800-63B (2017) deprecated periodic forced changes unless compromise is suspected. Frequent rotation produces weaker passwords—incremented numbers, predictable patterns—and does not prevent credential stuffing from already-stolen hashes. Change passwords when a service notifies you of breach, when you suspect phishing, or when reusing a password across sites becomes known.
Master password recovery is the catastrophic failure mode. Lose your master password with most managers, and your vault is cryptographically unrecoverable. This is by design. It also means your master password requires special treatment: highest entropy you can reliably memorize, stored in multiple physical locations (safe deposit box, trusted family member), never digitized outside the manager itself.
The generator connects to broader decisions: which manager to adopt, whether to enable breach monitoring, how to handle two-factor backup codes. These are not afterthoughts. They are the system that makes generated passwords useful.
What to Do Differently
Stop optimizing password memorability. The generator’s power is wasted if you truncate length to preserve memorability, or if you reuse its output across services. Generate one strong master password, store it in your brain and a physical backup, then let your manager create and store everything else at maximum length. The calculator’s numbers are not aspirational—they’re achievable, immediately, with the right workflow.
Informational Disclaimer
This content explains password generation mathematics and security practices for educational purposes. It does not constitute professional cybersecurity advice. For organizational security policies, compliance requirements, or threat modeling specific to your environment, consult a qualified information security professional.