Strong password generator

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Generate secure passwords regularly.

What is Strong password generator

Strong password generator helps you create unique, hard-to-guess passwords in seconds. Tired of weak patterns like “Password123”? The free Strong password generator by FlexiTools.io gives you quick controls for length, character sets, and readability so you can produce secure credentials on the spot. In the next 60 seconds, you can set length, pick which character types to include, generate a list, copy them, and export a CSV for safe record-keeping.

How to Use Our Strong password generator

  1. Choose length and how many
  • Set Password length and How many using the number fields. Longer passwords raise security - 16 or more is a great default.
  1. Pick character sets and options
  • Check the boxes for Lowercase, Uppercase, Numbers, and Symbols. Use Exclude ambiguous characters if you’ll read passwords aloud or type them manually. Keep Require each selected type on to ensure variety.
  1. Generate and review
  • Click Generate or press Enter. Each result shows a copy button, a strength label (weak, fair, strong, very strong), and an estimated bits value.
  1. Copy or export
  • Click Copy on any line or use Copy all to grab every password at once. Use Download CSV to save passwords with their bits and rating for controlled import into your manager.

Why FlexiTools.io Offers the Best Strong password generator

Fast, private, browser-based

All generation runs on your device - no data leaves your browser. It’s instant and keeps your inputs local.

Flexible rules that fit real use

Mix and match lowercase, uppercase, numbers, and symbols. Exclude ambiguous characters for readability and require each selected type for balanced complexity.

Copy and export without friction

Per-item Copy, a convenient Copy all action, and a clean Download CSV make it simple to move results into your workflow.

Clear strength feedback

Each password shows a rating and an estimated bits value, so you can aim for strong or very strong results with confidence.

FlexiTools.io vs typical alternatives

  • FlexiTools.io: Local generation and instant results - Alternatives: May require server calls or extra steps
  • FlexiTools.io: Copy all and CSV export built-in - Alternatives: Limited export or gated features
  • FlexiTools.io: Require-each-type and readability options - Alternatives: Rigid or opaque settings
  • FlexiTools.io: Clear bits estimate per password - Alternatives: No visibility into strength

A Deeper Look at Password Strength and Entropy

What “strong” really means

A strong password resists guessing - whether by an attacker trying common patterns or by automated tools that try many combinations. Short strings, predictable words, and simple substitutions are easy to crack. By contrast, long, random characters are much tougher to guess. That’s the entire point of a generator: create randomness you wouldn’t pick by hand.

Entropy in plain language

Entropy is a way to estimate how many guesses an attacker would need on average. Our tool shows an estimated bits value using a simple model: length × log2(character set size). More characters and more kinds of characters increase the search space, which boosts the bits estimate. This estimate helps you compare choices - for example, 16 characters from all four sets has far more combinations than 10 lowercase-only characters. It’s an estimate, not a guarantee, but it points you in the right direction.

Length usually beats fancy rules

Which helps more - adding a symbol or adding four more characters? In most cases, length wins. A 16-character password using three sets often beats a 10-character password that includes every set. If your systems allow long passwords, use that freedom. Keep Require each selected type enabled when policies need it, but remember the biggest gain usually comes from making strings longer.

Ambiguous characters - usability vs search space

Ambiguous characters like I, l, 1, O, 0, and | can be confusing. Excluding them improves readability if you must read codes over the phone or type from a print-out. This option slightly reduces the character pool, which reduces entropy a bit, but the trade-off can be worth it for real-world use. If you’re pasting into a password manager, you can leave ambiguous characters available to maximize strength.

Secure randomness in the browser

Good passwords start with good randomness. Modern browsers expose secure random number generation through the Web Crypto API. When available, this tool draws randomness from your browser’s cryptographic source for selection and shuffling. If you want to learn more, see MDN’s overview of the Web Crypto API and the W3C’s Web Cryptography API. Still wondering whether software can be predictable? High-quality randomness - plus sufficient length - is what makes brute-force guessing impractical.

A quick example

A school IT lead needed 30 unique, readable passwords for short-term test accounts. They set length to 14, enabled lowercase, uppercase, and numbers, turned off symbols, and checked Exclude ambiguous characters to avoid confusion during login. The list generated in one click, they used Copy all to paste into their admin panel, and saved a one-time CSV for that day’s rollout. Sign-ins went smoothly - no “Is that a zero or an O?” questions.

Handling and storage

Strong passwords help only if you handle them safely. Paste generated passwords into a trusted password manager rather than leaving them in notes or spreadsheets. If you export CSV for a one-time import, delete the file when you’re done and empty the recycle bin. Need multiple credentials? Generate fresh ones - reuse is the real enemy. Do you want easy-to-remember phrases instead? That’s a different approach, but for random strings, length and randomness are your best friends.

Pro-Tips for Getting the Most Out of Password Generation

  • Aim for 16-24 characters for accounts that matter - go longer if your system allows it.
  • Keep Require each selected type on, and only exclude ambiguous characters if readability is a must.
  • Use Copy all to move results into your password manager, or export CSV for a controlled import - then securely delete the file.
Is this Strong password generator free to use?
Yes. You can generate and download as many passwords as you need. Everything runs in your browser and your inputs stay on your device. No sign-in is required.
How does the tool measure strength?
Each password shows an estimated bits value and a rating from weak to very strong. The estimate is based on length and the size of the character set you selected. It’s a practical guide to compare options - longer and more diverse sets yield higher estimates.
What do “Exclude ambiguous characters” and “Require each selected type” mean?
Exclude ambiguous characters removes look-alikes like I, l, 1, O, and 0 for easier reading and typing. Require each selected type ensures the password includes at least one character from every set you checked. This avoids all-lowercase or all-numeric results. If you reduce sets or length, make sure the length is still high.
Can I copy or export multiple passwords at once?
Yes. Use Copy all to grab the entire list in one click. You can also select Download CSV to save passwords along with their bits and rating. Handle CSV files carefully and delete them after importing to your manager.
Does the tool store my passwords or send them anywhere?
No. Generation happens locally in your browser and results are displayed only on your screen. Reloading the page clears your results. For long-term storage, paste into your password manager.