Updated Security & Encryption Tool

Password Strength Calculator

Measure password strength using entropy, character classes, patterns, dictionary checks, and crack-time estimation. Analyze a single password or bulk list. Get instant security recommendations.

Entropy Score Crack Time Estimate Pattern Detection Bulk Analysis

Check Your Password Strength

Enter a password to see its strength score, estimated entropy, character set coverage and a rough crack-time estimate. Use bulk mode to quickly scan multiple passwords, or adjust the rules tab to match your own security policy.

No passwords are stored or sent to a server. Evaluation happens entirely in your browser.
Used for recommendations and rule-based warnings.
Defaults to 1012 guesses/second, typical for modern offline attacks.

The strength score combines entropy-based estimates with penalties for short length, repeated characters, common patterns and predictable substitutions (like "P@ssw0rd").

Each line is treated as a separate password. Lines that are empty are skipped. Nothing is sent to a server; all analysis is performed locally in your browser.

Bulk mode is ideal for quickly scanning exported password lists (for example from a password manager) to spot weak or reused passwords that should be changed.

Used as a guideline when flagging “too short” passwords in both single and bulk modes.
Length where the calculator starts labeling passwords as strong, assuming good character variety.
Used for crack-time estimates when per-tab overrides are left at zero or blank.
Any word added here will be treated as a weak pattern. Useful for organization-specific or personal terms that should never appear in passwords.

These rules define how the scoring engine interprets “weak” vs “strong” in your environment. They do not change the underlying entropy calculation, but they affect the final strength label and warnings.

Password Strength Calculator – Entropy, Score and Crack-Time Estimate

The Password Strength Calculator from MyTimeCalculator helps you understand how secure a password really is. It combines entropy-based math with practical checks for length, character variety, repeated patterns, common words and keyboard sequences. The result is an easy-to-read strength label, entropy estimate and a rough crack-time estimation under different guessing speeds.

You can analyze a single password or quickly scan an entire list in bulk mode. The rules tab lets you align the scoring model with your organization’s password policy or your own personal security goals.

1. What Makes a Password “Strong”?

In practice, a strong password has both high entropy and practical resistance to common attack strategies. This calculator considers:

  • Length: Longer passwords have more possible combinations and are usually harder to brute force, especially when combined with multiple character sets.
  • Character variety: Using a mix of lowercase, uppercase, digits and symbols increases the effective character set size and therefore entropy per character.
  • Patterns and repetition: Repeating the same character or using simple sequences like 123456 or abcdef reduces practical strength even if the theoretical entropy looks high.
  • Dictionary words and common phrases: Attackers often start with wordlists, leaked password databases and keyboard runs such as qwerty or password123.

The calculator uses entropy to estimate combinations, then applies penalties and warnings when it detects these patterns in your password.

2. Understanding Entropy and Crack Time

Entropy is measured in bits and represents the log2 of the number of possible combinations. For example:

  • 20 bits of entropy ≈ about 1 million possibilities.
  • 40 bits of entropy ≈ about 1 trillion possibilities.
  • 60+ bits of entropy is considered strong for many consumer scenarios.

To estimate crack time, the calculator assumes an attacker can try a certain number of guesses per second and uses the average number of guesses needed to find the password with brute force. The result is presented in seconds, minutes, hours, days, years or longer, depending on the magnitude.

3. How to Use the Password Strength Calculator

  1. Single password tab: Enter a password and, optionally, a label (such as “email account” or “banking”). Adjust the minimum length and guessing speed if needed, then click the button to see the score, entropy and warnings.
  2. Bulk password tab: Paste a list of passwords (one per line). The calculator masks each password in the output and shows relative strength so you can spot weak or reused passwords without revealing the full text.
  3. Rules & assumptions tab: Configure recommended length, “strong” length threshold, default guesses per second and which penalties should apply. You can also define custom words that should always be treated as weak, such as company names or usernames.

None of the passwords are stored or transmitted to a server from the calculator’s perspective; all checks are intended to run locally in the browser environment where the page is loaded.

4. Practical Tips for Creating Stronger Passwords

  • Prefer passphrases: Long, unique phrases with unrelated words (and some digits or symbols) are typically easier to remember and harder to guess than short, complex-looking strings.
  • Avoid personal information: Do not include names, birthdays, usernames, phone numbers, addresses or obvious company references that attackers can guess or find online.
  • Use a password manager: Password managers allow you to generate and store long, random passwords without having to memorize every single one.
  • Enable multi-factor authentication (MFA): Even a strong password is safer when combined with a second factor, like an authenticator app or hardware security key.

5. Limitations and Best Practices

No password strength calculator can perfectly model every real-world attack method. Attackers may have access to leaked password lists, organization-specific information or advanced cracking setups. For that reason:

  • Use the calculator as a guide, not as an absolute guarantee of security.
  • Combine strong passwords with MFA wherever possible.
  • Rotate passwords if you suspect a breach or if a service experiences a data leak.

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Password Strength Calculator FAQs

Frequently Asked Questions

Quick answers to common questions about password strength scoring, entropy, crack-time estimates and privacy considerations when using this calculator.

The calculator is designed to evaluate passwords directly in your browser session. The logic runs on the page and does not need to send your password to another location for analysis. However, you should still avoid testing extremely sensitive passwords on shared or untrusted devices, and always keep your system free of malware and keyloggers for the best security posture.

Entropy measures how unpredictable a password is based on its length and the variety of characters it can contain. It is expressed in bits, which roughly correspond to powers of two. More bits mean more possible combinations for an attacker to try. The calculator uses entropy to estimate how many guesses would be required to brute-force the password under a given attack speed.

Length alone is not enough. If a long password contains repeated characters, simple sequences or common words, real-world attackers can guess it much faster than a random string of the same length. The calculator applies penalties when it detects those patterns, which can reduce the overall strength label even when the raw entropy looks high on paper.

No tool can offer an absolute guarantee that a password is uncrackable. The calculator provides estimates based on simplified assumptions about attacker capabilities and brute-force strategies. In practice, attackers may have more targeted information or use smarter techniques. Consider these results as guidance for better password hygiene, not as a strict security certification.

Organizations can use the bulk mode with masked output to identify weak or reused passwords in exported reports without exposing the full credentials on screen. Combined with strict password policies, MFA and centralized access controls, the calculator can help prioritize which accounts or systems may need immediate password updates or additional security hardening.