What is PolymarketOddsConverter (extension)?
The toolbar icon switches conversion on or off, letting users compare familiar sportsbook-style decimals with probability. Decimal odds are the reciprocal of probability expressed as a fraction; this gross display does not incorporate fees or liquidity.
Installation uses the repository and browser developer tools rather than a hosted account. Chrome and Firefox have separate manifests and background implementations. The Firefox instructions describe a temporary add-on, and Polymarket layout changes can affect an extension that rewrites displayed values.
Who it is for
- Users familiar with decimal sportsbook odds.
- People comparing display formats.
- Users comfortable loading unpacked extensions.
Features and coverage
- Decimal display
Convert visible implied probabilities to decimal odds.
- Toolbar toggle
Enable or disable conversion without removing the extension.
- Chrome
Browser-specific manifest and service-worker background.
- Firefox
Separate manifest and background script.
- Local install
Load repository files without a hosted account.
Workflows with PolymarketOddsConverter (extension)
Read familiar units
Install the correct browser version, open Polymarket and toggle the display.
Compare formats
Switch between representations while keeping the original contract rules visible.
Pricing and total cost
No subscription or paid unlock is listed. Install manually through browser extension developer tools.
Getting started
Before you start: Firefox installation is temporary in the documented route.
- Download the repository.
- Rename the chosen browser manifest to manifest.json in that copy.
- In Chrome, enable Developer mode and load the unpacked directory.
- In Firefox, load a temporary add-on through the debugging page.
- Open Polymarket and check the toolbar toggle.
Chrome and Firefox require different manifests.
Useful links
What to check
- Firefox installation is temporary in the documented route.
- Conversion changes presentation only; fees and liquidity still matter.
- Page-layout changes can disrupt value rewriting.
A closer look
Ratings & reviews
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Browse categoryFrequently asked questions about PolymarketOddsConverter (extension)
Does it change order prices?
No. Only presentation changes.
How are the formats related?
Gross decimal odds are the reciprocal of probability expressed as a fraction.
Can I disable it quickly?
Use the toolbar icon.
Can both browsers share a manifest?
The repository supplies separate Chrome and Firefox manifests.


