Fair-odds de-vigger
Enter a market’s prices and strip the bookmaker’s margin to reveal the fair odds — the closest estimate of each runner’s true chance.
| Runner | Book odds | Proportional | Power |
|---|
De-vig 60+ books at once
EVSTREAM de-vigs every bookie in real time — Proportional, Power and Shin
Two ways to remove the margin.
- ▸Proportional scales every runner’s implied probability down by the same factor until they sum to 100%. Simple, fast, stable — the everyday default.
- ▸Power raises each implied probability to an exponent k so they sum to 100%. Because it bends the curve, it shaves more margin off longshots than favourites — correcting the favourite–longshot bias and usually landing closer to sharp pricing.
- ▸Tick “compare methods” to see both at once. The gap is biggest on the roughies — exactly where the bookmaker pads hardest.
De-vigging, answered.
Removing the margin is the step between a bookmaker's price and a runner's real chance.
What is de-vigging?
De-vigging removes the bookmaker’s margin (the overround) from a market so the runners’ probabilities sum to 100%. What is left is the fair price — the closest estimate of each runner’s true chance hidden inside the padded prices.
Proportional vs Power — what is the difference?
Proportional scales every implied probability down by the same factor. Power raises them to an exponent so they sum to 100%, which shaves more margin off longshots than favourites — correcting the favourite–longshot bias and usually landing closer to sharp pricing.
Which method should I use?
Proportional is the simple, stable default. Power tends to be more accurate on long-priced, over-padded fields. Toggle "compare" to see both side by side — the difference is biggest on the roughies.
Is the de-vigged price the true chance?
It is the best estimate from one book’s prices. Sharper still is de-vigging many books and blending them — which is exactly what EVSTREAM does across 60+ bookies in real time.
One book is a guess. Sixty is an edge.
EVSTREAM de-vigs and blends 60+ bookmakers in real time, so your fair odds aren't built from a single padded market.