Web app · Finance
Volsense
Implied vol for prediction markets — log the range, read the IV
Event contracts publish a price but never an implied vol. Log a market's mid plus the week's high and low, and Volsense returns a weekly IV, an expected move in cents, an IV rank and a richness read that says whether the premium is fat or crowded. Free, no install, no exchange connection.
Stored in your browser only. Nothing you do in the web version is sent to our servers. Clear your browser data and it's gone — so export a backup from the in-app menu if you want to keep it.
In your browser
What you can do in Volsense on the web
Two real vol estimators
Parkinson's high–low estimator, ln(high ÷ low) ÷ (2·√ln2), or the desk rule of four, (high − low) ÷ (4 × mid). Switch in Settings; annualising multiplies by √52.
Richness, not just vol
Volsense scales your weekly vol out to the resolution date and compares it with √(p(1−p)) ÷ p — the most a binary at that price can actually deliver. Above 0.95× screens rich to sell, below 0.55× screens crowded.
Vol map of the whole book
Every tracked contract drawn as its week's low-to-high band on a 0–100¢ scale with a mid tick, coloured by richness band.
Weekly quote log and IV rank
Log a mid/low/high snapshot each week; Volsense charts the IV history and tells you where today's vol sits inside that market's own range, 0–100.
Screener with CSV export
Filter by book (Kalshi, Polymarket, PredictIt, Manifold, Metaculus), sort by IV, richness, expected move or resolution date, and download the whole screen as CSV.
A journal, never a broker
No exchange connection, no live prices, no orders. Every number comes from what you typed and stays in this browser.
Screens
Every screen, rebuilt for the browser
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1
Book
Median IV across your open markets, the vol map, and every contract ranked by implied vol.
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2
Market detail
Weekly and annualised IV, expected move, richness gauge, the tape, the traded range and the full quote log.
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3
Market editor
Label, book, category, mid, week low/high and resolution date, with the IV, move and richness previewed as you type.
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4
Log a quote
Add this week's mid, low and high for a market and optionally make it the live quote.
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5
Screener
Sort and filter the whole book by IV, richness, expected move or resolution date, with a richness-band donut and CSV export.
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6
Method
The formulas behind every number, how to read the richness bands, and what Volsense deliberately is not.
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7
Settings
Estimator, weekly vs annualised headline, richness thresholds, default book, backup and erase.
Try it with sample data: Loads ten event contracts across Kalshi, Polymarket, PredictIt and Manifold — each with five weeks of logged mid/high/low quotes — plus one settled CPI market. You can start fresh at any time.
Ready? It's free.
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Questions
Is the web version of Volsense free?+
Yes. Sign in with a free All Things AI account and use every screen — no subscription, no in-app purchases.
Where is my data stored?+
Only in this browser's local storage. Nothing you enter is sent to our servers, so we can't see it, back it up, or restore it. Clearing site data, a private window, or another device starts empty. Export a backup from the in-app menu to keep it.
Do I need an account?+
You can read about the app without one, but you must sign in to open it. Sign-in is free and takes a few seconds with Google.
How is the web version different from the Volsense iPhone app?+
Volsense never connects to Kalshi, Polymarket or any exchange: you type the mid, high and low yourself, exactly as on iPhone. The IV is a range-based estimate from one week of prices, not an option-implied surface — there is no options chain behind an event contract. Markets and quotes are saved in this browser only; the iPhone app keeps them in SwiftData on device. Export a JSON backup to move them.