A ledger for prediction-market calls
Log your Kalshi and Polymarket calls. Let the market grade them.
PredictLedger records each position you take, waits for the market to resolve, then scores you the way forecasters are scored: Brier score, calibration curve and P&L, on a public profile you can share.
Start your ledger free How scoring works
Free ledger and public profile. Pro adds the deep stats for $9/mo.
Three steps, no exchange login
- Log a callPick the market, enter your side, price and size. Add your own probability if you want calibration scored too.
- The market resolves itWe mirror public market data and resolutions from Kalshi and Polymarket. You never hand us an account or API key.
- Read your scorecardBrier, calibration and P&L on your profile. Share a call or your whole record with one link.
Why a ledger, not a screenshot
Scored like a forecaster
The Brier score rewards being right and confident, and punishes being confident and wrong. Calibration shows whether your 70% calls land 70% of the time. P&L shows what it cost or paid.
Against the crowd
Every call is compared with the market price at the moment you logged it. A positive skill score means you added information the market did not have yet.
Public record, your choice
Your profile shows what resolved and how you did. Open calls stay hidden until they resolve. Pro users can keep the whole ledger private.
Pricing
Free
$0
- Log calls on Kalshi and Polymarket markets
- Brier score, win rate and P&L on resolved calls
- Public profile at predictledger.9gg.app/u/you
- Share any resolved call with one link
- Last 30 days of history
Pro
$9/mo or $79/yr
- Everything in Free
- Calibration curve and Brier skill vs the market price
- Splits by exchange and category, full history
- Time-averaged Brier and streaks
- Private ledger mode and CSV export
- Email when a logged market resolves
Cancel any time. First purchase refundable on request within 14 days.
Who it is for
People who trade on Kalshi or Polymarket and want an honest record of their own judgment, not a feed of other people's hot takes. Forecasting hobbyists who want a Brier score for real-money calls. Writers and researchers who want a public track record they can point at.
PredictLedger is an information service. It does not place orders, hold funds or connect to your exchange account. Nothing on this site is a recommendation to trade. Read the disclaimer.
Opening soon
The ledger is in its last build. Leave your email and we will send one message when it opens.
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