Know if you’re
actually calibrated.
You trade Kalshi or Polymarket on vibes-plus-research. But is your 70% really a 70%? BrierDesk is a calibration-first trade journal: log your probability on every position, resolve it when the event settles, and your Brier score — the average squared gap between what you predicted and what happened, where 0 is perfect and 0.25 is coin-flip guessing — tells you the truth your P&L hides.
No account, no password: your workspace lives behind a secret link. Free covers your first 20 forecasts.
Why calibration, not just P&L
Prediction markets — Kalshi and Polymarket alone did roughly $76B in combined trailing-year volume (2026) — pay you for having better probabilities than the crowd. P&L tells you what happened; it can’t separate skill from variance on small samples. Calibration tells you whether your stated probabilities mean anything — and that’s the input you actually control.
How it works
- Create a workspace. Name it, get a secret link. The link is the login — bookmark it.
- Log forecasts as you trade. The question, your probability, the market price at entry if you want the comparison, an optional stake and thesis.
- Resolve YES or NO when the event settles. Your probability locks at resolution — the record can’t be flattered after the fact.
- Read the dashboard. Brier score, calibration curve, category breakdown, rolling trend, and you-vs-the-market on every trade where you logged the entry price.
The honesty rule (it’s built in)
Under 10 resolved forecasts, BrierDesk refuses to show you a headline score — it says “too few resolved forecasts for a stable read” instead. Calibration-curve buckets with fewer than 5 observations render hollow, with their counts labeled. A journal that implies precision its sample size can’t support is lying to you, and lying to yourself is the one edge-killer no strategy survives.
The dashboard
Brier score
One number for your forecast accuracy — with the sample size right next to it.
Calibration curve
Your predicted probabilities vs what actually happened, decile by decile. The gap IS your bias.
Per-category table
Politics, sports, econ, crypto, weather — find out where your edge actually lives.
You vs the market
On trades where you logged the market price: whose probability was closer to reality?
Score over time
Rolling last-20 Brier — see whether you are improving or tilting.
Locked at resolution
Once a forecast resolves, your probability is frozen. No retro-editing, no flattering yourself.
Pricing
Free
- 20 forecasts per workspace
- Full dashboard: Brier, calibration curve, categories, vs-market
- Secret-link access, no account
Pro
- Unlimited forecasts
- CSV import of your trade history
- Download your reliability diagram (SVG)
BrierDesk is a journaling and scoring tool — not trading advice, and it executes nothing. Built by AEQUARA, the calibration company. Questions? hello@aequara.ai — a human reads it.