Password Reuse Exposure Calculator
Privacy: this tool never asks for your actual password. Everything below is numbers only, calculated entirely in your browser — nothing is sent anywhere.
Because your email is in the mix, a leak can cascade further — attackers often use a compromised email to reset passwords on your OTHER accounts too, even ones that don't share this password.
For context: in a 2025 analysis of 19 billion leaked passwords, 94% were reused or duplicated across accounts (Cybernews).
See the illustrative blast radius of reusing one password across accounts — enter how many accounts share it and whether they include email, banking, or social accounts, and see how many become at-risk if just one of those sites leaks. 100% client-side: never accepts or transmits an actual password.
How it works
- Slide to set how many accounts currently use this exact password
- Toggle whether your email, bank, or social accounts are among them
- See how many accounts are at risk if just one site with that password leaks, plus a cascade warning if your email is included
Frequently asked questions
Do I need to type my actual password?
No, never. This tool only asks for numbers (how many accounts reuse the password) and yes/no toggles (does it include your email, bank, or social accounts). It never asks for, stores, or transmits the password itself.
Does this check my password against a breach database?
No. Unlike breach-lookup tools, this calculator makes no network requests at all — it's a purely illustrative estimate based on the numbers you enter, calculated entirely in your browser.
Why does including my email matter so much?
If an attacker gets into your email account, they can typically use 'forgot password' flows to reset passwords on many of your other accounts — even ones that don't share the leaked password. This creates a cascade effect beyond the accounts that reused the password directly.
How common is password reuse really?
In a 2025 Cybernews analysis of over 19 billion leaked passwords collected between April 2024 and April 2025, 94% were found to be reused or duplicated across different accounts.
Related tools
From the blog
Update history
- 2026-09-29 Launched: illustrative, fully client-side calculator showing how many accounts become at-risk if a reused password leaks — takes only numeric/toggle inputs, never accepts or transmits an actual password string.