Model limits
Entropy is a guessing-resistance estimate. It is not a guarantee against phishing, malware, compromised sites, password reuse, weak account recovery or missing multi-factor authentication.
Developer & IT
Password Generator
Generate a real random password locally, then read the entropy so the strength is visible instead of guessed.
Generator
Generate a random password
Generated password•••• •••• •••• •••• ••••
20 characters from a 87-character pool gives 128.9 bits of entropy. This page generates locally in your browser; nothing is sent to a server.
Strength
Entropy and search space
Use it in code
Generate the same kind of password locally
import math
import secrets
import string
length = 20
characters = ""
characters += string.ascii_lowercase
characters += string.ascii_uppercase
characters += string.digits
characters += "!@#$%^&*()-_=+[]{};:,.<>?"
password = "".join(secrets.choice(characters) for _ in range(length))
entropy_bits = length * math.log2(len(characters))
print(password)
print(f"pool={len(characters)} entropy_bits={entropy_bits:.1f}")Both snippets print a generated password, then pool=87 entropy_bits=128.9 for the current controls.
Worksheet
Password planning worksheet
- Pick a unique password for one account only; never reuse it.
- Use a trusted password manager to store the generated value.
- Record the length, character sets and entropy, not the secret itself.
- Turn on multi-factor authentication where the account supports it.
Method
Why this page exists
Search intent: generate a secure random password and understand its strength before storing it.
Nearest sibling: random-number-generator-calculator creates numbers for simulation or selection; this page creates account secrets with password-specific controls and safety notes.
The generator uses the browser's cryptographic random source and rejection sampling so each selected character is chosen without modulo bias. The password appears above the fold, and the strength meter shows the same state as entropy bits and approximate search space.
The memorable rule is simple: a password is not strong because it looks noisy; it is strong because it was randomly chosen from a large space and never reused. The meter turns that invisible search space into a number you can compare.
Entropy is calculated as length multiplied by log2 of the selected character-pool size. That is a useful random-guessing model, but it does not cover phishing, malware, breached websites, password reuse or recovery questions. Use a password manager and multi-factor authentication for real accounts.
Sources
References checked for this tool
Questions people ask
Password Generator: frequently asked questions
Does this password generator send my password anywhere?
No. The password is generated in your browser with crypto.getRandomValues and is not uploaded by the page.
Why does length matter so much?
A random password gains entropy with every extra character. Length usually improves strength more reliably than making a short password look complicated.
Should I remember the generated password?
Usually no. Use a password manager so every account can have a long unique password without reuse.
Are symbols required?
Symbols increase the character pool, but a longer random password without symbols can still be stronger than a short password with them.
Is entropy the same as total account safety?
No. Entropy measures random guessing resistance. Phishing, malware, password reuse, breached sites and missing multi-factor authentication are separate risks.
Certification notes
Source, method and limitation basis
Dedicated password generator page with real secure generation, entropy proof, copy controls, code snippets and worksheet. Reviewed 2026-09-30.
Assumptions
- Passwords are generated in the browser and are not intentionally transmitted by this page.
- Entropy assumes independent random draws from the selected character pool.
- A unique password manager entry is safer than a reused or human-invented password.
Cite this page
Use the canonical URL, the page title “Password Generator - CalculationTime”, and the review date 2026-09-30.
Sources and further readingNIST SP 800-63B Digital Identity GuidelinesOWASP Authentication Cheat SheetMDN Crypto.getRandomValues()