How to Generate a Strong Random Password on Windows

A strong password isn't something you should try to invent yourself. Human-generated passwords follow predictable patterns that automated cracking tools exploit. The only reliable approach is true randomness — and that's exactly what a password generator provides.

This guide covers the best ways to generate strong, random passwords on Windows — from a dedicated free desktop tool to built-in PowerShell commands. We'll also explain exactly what makes a password strong and how long yours should be for different use cases.

What Makes a Password Truly Strong?

Password strength is determined by two factors: length and character variety. Together these determine the total number of possible combinations — known as the password's entropy. The higher the entropy, the longer it takes to crack.

The critical insight here is that length matters more than complexity. A 20-character password using only lowercase letters is harder to crack than a 10-character password with all character types. But using all character types at a good length is the strongest approach.

Method 1: SterJo Strong Password Generator

SterJo Strong Password Generator is a free, portable Windows tool that creates cryptographically strong random passwords instantly. You control the character set and length — it handles the randomness.

Step-by-Step:

1. Download SterJo Strong Password Generator (1.6 MB, installer or portable)
2. Run the tool — no installation needed for the portable version
3. Set the password length — 16 characters minimum, 20+ for sensitive accounts
4. Select your character set: uppercase letters, lowercase letters, numbers, special symbols
5. Set quantity: one password, or generate a bulk list
6. Click Generate
7. Use the one-click copy button to copy the password to your clipboard

For Developers: Bulk Password & License Key Generation

SterJo Strong Password Generator also includes a dedicated license key generation mode — useful for developers who need to create unique serial numbers, activation codes, or unlock keys for software products. Generate as many as needed in a single batch, all cryptographically unique.

Method 2: PowerShell — No Download Needed

Windows PowerShell has a built-in method to generate strong passwords without any additional tools:

Method A — Using the Membership class:

Add-Type -AssemblyName System.Web
[System.Web.Security.Membership]::GeneratePassword(20, 4)

This generates a 20-character password with at least 4 non-alphanumeric characters. Change the numbers to adjust length and complexity.

Method B — Custom character set:

$chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#$%^&*()'
$password = -join ((1..20) | ForEach-Object { $chars[(Get-Random -Maximum $chars.Length)] })
$password

This generates a 20-character random password from a custom character set. Change 1..20 to adjust the length.

Method 3: SterJo Wi-Fi Key Generator — For Network Passwords Specifically

If you specifically need a strong WiFi password, SterJo Wireless Key Generator generates strong, random keys optimized for WPA2/WPA3 WiFi networks — with appropriate character sets and lengths that work reliably across all WiFi devices.

How Long Should Your Password Be?

Different situations call for different password lengths:

What to Do After Generating a Password

Generating a strong password is only half the job. How you store and use it matters just as much:

• Use a password manager — Tools like Bitwarden, KeePass, or 1Password store all your passwords securely. You only need to remember one master password.
• Never reuse passwords — Each account should have its own unique password. If one site is breached, the others remain safe.
• Never store passwords in plain text — Don't save them in a Notepad file or an Excel sheet without encryption.
• Enable two-factor authentication (2FA) — A strong password plus 2FA means an attacker needs both your password and physical access to your phone or authenticator app.
• Don't share passwords over email or chat — These channels are not secure. Use a password manager's built-in sharing feature if you need to share credentials.

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