Opportunity Cost

See every price in satoshis. Understand the Bitcoin opportunity cost of your purchases.

Think in sound money, everywhere you browse. Opportunity Cost instantly shows the price of products and services in bitcoin ( ₿ / sats ) next to the original fiat amount. No more mental math or tab-hopping to converters—just a constant reminder of what spending really costs in Bitcoin terms. Key features Automatic price detection & conversion – Detects 10+ local currencies and shows the live satoshi equivalent right on the page. Real-time rates – Pulls spot prices from reliable Bitcoin exchanges every ~30 seconds for up-to-date conversions. Inline or tooltip display – Choose a subtle gray sats value beside the price, or a tooltip that appears on hover. Dark mode support – Looks great in light or dark themes, automatically matching your browser’s appearance. Quick toggle – Click the toolbar icon to pause/enable on the current site or everywhere. Customisable – Pick your preferred currency, number format (sats / BTC), display precision and refresh interval. Zero sign-up, zero tracking – We collect no personal data. All parsing and settings storage happens locally (via IndexedDB); the only outbound request is for a BTC/FIAT price feed. Open-source – View the code, file issues or contribute on GitHub. Permissions note This extension uses the tabs permission solely to support per-site toggling, allowing you to enable or disable Bitcoin pricing on specific websites.