Opportunity Cost
Free browser extension that converts every fiat price you see online into Bitcoin or sats in real-time.
Why We Recommend Opportunity Cost
Opportunity Cost takes a refreshingly simple approach to Bitcoin education by meeting users exactly where they already spend time—browsing the web. The extension automatically detects prices across any website and displays their Bitcoin equivalent inline, eliminating the friction of constantly opening calculators or exchange apps. With support for 10+ fiat currencies, customizable display options (BTC or sats), dark mode, and per-site toggles, it delivers a polished experience that stays out of your way while fundamentally shifting how you perceive prices.
The privacy-first architecture is a standout feature. All price detection and conversion happens locally in your browser—no page content or personal identifiers are sent to remote servers. The only network request is fetching current BTC exchange rates, with no user data attached. Optional local statistics (like conversion counts) can be disabled or cleared anytime from the options page. Being fully open-source on GitHub, backed by established Bitcoin media outlet TFTC, and created by known Bitcoiners Marty Bent and Moses Finlay adds meaningful transparency. There's no account required, no ads, no subscription fees, and no monetization—just a free tool designed to help you think in sound money terms.
Best For
Opportunity Cost is ideal for Bitcoiners who want to internalize what purchases actually cost in sats. Whether you're browsing Amazon, reading news with price mentions, or comparing subscription services, seeing the Bitcoin equivalent creates a powerful mental framework for spending decisions. The extension helps you viscerally feel the opportunity cost of fiat spending—that $50 impulse purchase suddenly registers differently when you see it's 80,000 sats you could have stacked instead.
Content creators and Bitcoin educators will find it particularly useful for generating screenshots and examples that illustrate Bitcoin's value proposition. Instead of manually calculating conversions, you can simply browse any site and capture real-world prices displayed in sats for social media posts, presentations, or articles. The visual impact of seeing everyday items priced in Bitcoin makes abstract concepts concrete for newcomers.
Newcomers curious about Bitcoin will appreciate the zero-friction onboarding—install once and you're immediately "thinking in Bitcoin" without learning new apps or workflows. It transforms ordinary web browsing into passive Bitcoin education, making the transition to a sound money mindset gradual and natural rather than requiring dedicated study time.
Services & Features
- Automatic fiat-to-BTC conversion
- 10+ supported fiat currencies
- Sats or BTC denomination choice
- Per-site toggle controls
- Customizable display precision
- Dark mode support
- Local-only data processing
- Chrome and Brave support
- Firefox support emerging
Considerations
Browser extension only—no mobile app available, so it won't help when shopping on your phone. Conversion accuracy depends on the project's price API remaining online. As with any extension requiring page content access, stick to official store listings and keep it updated.
