How to use this random password generator
Choose a length from 8 to 128 characters, then select at least one character type: uppercase letters, lowercase letters, numbers, or symbols. Keep Exclude ambiguous characters selected if you may need to read or type the password manually. Select Generate password, review the result, and use Copy password to place it on your clipboard. Generate a separate password for every account.
How the calculation works
The generator builds a character pool from the options you select. It first chooses at least one character from every selected group, fills the remaining positions from the combined pool, and then shuffles the complete password. This ensures that each enabled character type is represented without placing those required characters in predictable positions.
Random choices use the browser's cryptographic random source and rejection sampling, which avoids the small bias created by simply taking a random value modulo the pool size. Generation happens locally in a compatible browser. A strong generated password should still be stored in a reputable password manager, never reused, and changed promptly if an account or device may have been compromised.
Formulas
Unconstrained possibility count
Approximate password entropy
Worked examples
A password-manager password
Select all four character types and a length of 20 or more. Save the generated password directly in your password manager instead of trying to memorize or reuse it.
A code that must be typed manually
Choose a length allowed by the service and exclude ambiguous characters such as O, 0, I, l, and 1. The result remains random but is easier to transcribe accurately.
Common uses
Unique account passwords
Generate a different long password for email, shopping, financial, social, and work accounts. Save it directly in a reputable password manager instead of reusing a memorable pattern.
Device and network credentials
Create random credentials for routers, local devices, or services that accept ordinary passwords. Check the product's permitted length and characters before choosing the generator options.
Safer manual entry
Exclude ambiguous characters when a password must be read or typed by hand. Increasing length generally preserves strength better than replacing randomness with predictable words or personal information.
Accuracy and limitations
Generation uses the Web Crypto API, includes every selected character group, and securely shuffles positions. The result remains on the device, although browser extensions, clipboard history, or compromised software may still observe it.
This tool is not intended to create encryption keys, recovery seeds, API secrets with a required format, or regulated credentials. Follow the specification or security policy for those uses.
Frequently asked questions
Are generated passwords sent to NumUtility?
No. Generation runs in your browser, and the password is not sent to or stored by NumUtility. Your operating system or browser may retain clipboard history, so clear it when appropriate.
What password length should I choose?
Use the longest password the account accepts. For most accounts, 16 or more random characters is a practical baseline, while especially important accounts benefit from 20 or more.
Why must I select at least one character type?
A password needs an eligible character pool. Select the types accepted by the website or application where the password will be used.
Does every selected character type appear?
Yes. When the password length is valid, the generator includes at least one character from every selected group and securely shuffles their positions.
Can I use this to create encryption keys?
Use a purpose-built key-generation tool and follow the relevant cryptographic specification for encryption keys, recovery seeds, API secrets, or regulated security systems.
Should I reuse a generated password?
No. Use a unique password for every account and store it in a reputable password manager. Reuse allows one breach to endanger several accounts.
Is the random password generator free to use?
Yes. NumUtility is free, requires no account, and places no limit on ordinary calculations.
Are my entries stored?
No. The calculation runs in your browser. Values entered into the tool are not sent to NumUtility or saved by us.