Overview
Append sportsbook-style odds next to prediction market prices (Decimal, American, Fractional) with optional fee adjustment.
Chrome extension that appends sportsbook-style odds next to prediction market prices on Polymarket and Kalshi. Shows Decimal, American, and Fractional. Optional fee adjustment (in percentage points) to model effective probability before conversion. - Finds text like `55%` or `$0.55` and computes: - Decimal: 1 / p - American: if p >= 0.5 → -(p/(1-p))*100, else ((1-p)/p)*100 - Fractional: (1 - p) / p as a simplified fraction (approx.) - Works on SPA updates using a `MutationObserver`. - Avoids duplicate badges via a data-attribute.
Details
- Version1.2.0
- UpdatedOctober 6, 2025
- Size13.15KiB
- LanguagesEnglish
- Developer
Email
samkbe@gmail.com - Non-traderThis developer has not identified itself as a trader. For consumers in the European Union, please note that consumer rights do not apply to contracts between you and this developer.
Privacy
This developer declares that your data is
- Not being sold to third parties, outside of the approved use cases
- Not being used or transferred for purposes that are unrelated to the item's core functionality
- Not being used or transferred to determine creditworthiness or for lending purposes
Support
For help with questions, suggestions, or problems, visit the developer's support site
