Security Tools

Advanced Password Generator (with Custom Rules)

Generate highly secure passwords with advanced custom rules, entropy calculation, and time-to-crack estimation. Perfect for cybersecurity professionals and security-conscious users.

advanced5-10 minutesRuns in your browser
password

Interactive workspace

Inputs stay on your device — nothing is sent to our servers unless you choose to share.

Client-side only

Basic Settings

Security Notice

This advanced password generator uses cryptographically secure random generation entirely in your browser. No data is sent to our servers or stored anywhere. For maximum security, use generated passwords immediately, clear your clipboard after use, and consider using a password manager for storage.

Documentation

How to use this tool, practical use cases, and technical notes.

The Advanced Password Generator is designed to be usable in under 2 minutes for a standard strong password, and under 10 minutes for a fully configured, policy-tuned batch. Here is a complete step-by-step guide.

Step 1 — Set Your Password Length

The Password Length slider defaults to 16 characters, which is the current industry baseline for strong passwords. Adjust this based on your use case:

Use Case

Recommended Length

Approximate Entropy (Full Pool)

Low-risk accounts (forums, newsletters)

12 characters

~78 bits

Standard accounts (email, social)

16 characters

~105 bits

High-value accounts (banking, SSO)

20 characters

~131 bits

Service account / API credentials

24 characters

~157 bits

Master password / password manager

28–32 characters

~184–210 bits

Encryption key material (pre-hash)

32+ characters

~210+ bits

Rule of thumb: Every additional character multiplies the search space by the size of your character pool. With a 94-character pool, adding one character makes the password ~94× harder to brute-force.

Step 2 — Set the Generation Count

The Generate Count field controls how many passwords are produced in a single batch. Best practice is to generate 3–5 passwords and select the one that:

  • Has the highest entropy score (displayed alongside the password)

  • Passes a mental "typability" check if the password will ever need to be typed manually

  • Does not accidentally resemble a dictionary word or common pattern

Generating multiple passwords and selecting the strongest one effectively raises your practical security floor without changing any settings.

Step 3 — Configure Character Sets

Toggle the four character set checkboxes based on your requirements:

Toggle

Effect on Password

When to Enable

Uppercase (A–Z)

Adds 26 characters to pool

Almost always — required by most policies

Lowercase (a–z)

Adds 26 characters to pool

Always — highest frequency characters

Numbers (0–9)

Adds 10 characters to pool

Almost always — required by most policies

Symbols (!@#$%^&*)

Adds ~32 characters to pool

Enable for maximum entropy; check if system accepts all symbols

⚠️ Important: Some systems (legacy applications, certain databases, SSH key files) have restrictions on which symbol characters they accept in passwords. If you encounter authentication errors after setting a symbol-containing password, check the system's accepted character list and use the "Exclude Characters" field in Advanced Settings to remove problematic symbols.

Step 4 — Enable "Exclude Similar Characters"

Toggling Exclude Similar (il1Lo0O) removes the following visually ambiguous characters from the pool:

Character

Ambiguous With

l (lowercase L)

1 (one), I (uppercase i)

1 (one)

l (lowercase L), I (uppercase i)

I (uppercase i)

1 (one), l (lowercase L)

L (uppercase L)

1 (one), l (lowercase L)

o (lowercase o)

0 (zero)

0 (zero)

o (lowercase o)

O (uppercase O)

0 (zero)

When to use: Enable this when the password might ever need to be read from a screen and typed manually — e.g., printed credentials, phone-read passwords, or temporary credentials handed to users. This reduces your pool by ~7 characters but dramatically reduces transcription errors.

When to skip it: For passwords stored and pasted exclusively from a password manager, similar character exclusion provides no benefit and marginally reduces entropy.

Step 5 — Configure Advanced Settings

Expand the Advanced Settings panel to access custom rules and the character exclusion list.

Custom Rules

Rule

What It Prevents

Example of Prevented Pattern

No Consecutive Characters

Three or more identical characters in a row

aaa, 111, !!!

No Common Patterns

Keyboard walks and known weak sequences

qwerty, 123456, abcdef, zxcvbn

No Repeating Pairs

Alternating two-character sequences

abab, 1212, xyxy

Balanced Symbols

Guarantees at least one symbol character

Prevents all-alphanumeric output when symbols are enabled

Mixed Case Required

Guarantees both uppercase and lowercase

Prevents all-uppercase or all-lowercase output

Recommendation: Enable all five rules for maximum policy compliance and to eliminate the small probability that a CSPRNG-generated password accidentally contains a weak pattern.

Performance note: Enabling multiple custom rules causes the generator to retry candidate passwords until all rules are satisfied. This is imperceptible for lengths up to 32 characters but may add a small delay for very short passwords with strict rules.

Exclude Specific Characters

The Exclude Characters text field lets you remove any specific character from the pool. Common use cases:

Exclusion Scenario

Characters to Exclude

MySQL password fields (quote issues)

' " `

Shell scripts (variable expansion)

$ ` !

Windows CMD environment

% ^ &

URL query parameters

? & = + #

PostgreSQL connection strings

@ ' ;

JSON configuration files

" \

Mainframe / legacy COBOL systems

Most symbols — restrict to [A-Za-z0-9]

Step 6 — Generate and Review

Click Generate Passwords. For each generated password, review:

  • The password string — the credential itself

  • Entropy score — bits of entropy; aim for 80+ bits minimum

  • Time to crack estimate — how long brute-force would take at various attack speeds

  • Strength rating — a qualitative label (Weak / Moderate / Strong / Very Strong / Exceptional)

Step 7 — Copy and Use

Click the copy button adjacent to your selected password. Best practices for handling the password after copying:

  1. Paste immediately into your password manager, vault, or target system

  2. Do not paste into a notes app, email, or chat window

  3. Clear your clipboard after use (most OSes: copy a blank character or a meaningless string)

  4. On macOS, use pbcopy /dev/null or a clipboard manager with auto-clear

  5. On Windows, echo off | clip clears the clipboard from the command line