Here's a question: does a meter actually help people secure their accounts? It's less important than other areas of web security, a short sample of which include:

• Preventing online cracking with throttling or CAPTCHAs.
• Preventing offline cracking by selecting a suitably slow hash function with user-unique salts.
• Securing said password hashes.
• With that disclaimer — yes. I'm convinced these meters have the potential to help. //

As an independent Dropbox hackweek project, I thought it’d be fun to build an open source estimator that catches common patterns, and as a corollary, doesn’t penalize sufficiently complex passphrases like correcthorsebatterystaple. It’s now live on dropbox.com/register and available for use on github. Try the demo to experiment and see several example estimations.