No-Vig Calculator

Strip the bookmaker margin from a market to see the true fair odds.

Odds format

Outcomes

Outcome 1

Outcome 2

Method

Total implied probability104.76%

Vig (overround)4.76%

Outcome 1 fair50.00% · 2.000 · -100

Outcome 2 fair50.00% · 2.000 · -100

Each line shows fair probability · fair decimal odds · fair American odds. A total under 100% means the prices already include an arbitrage. Fair odds are an estimate: no-vig methods differ most on heavy favourites and long shots. Not financial advice.

Prediction markets have far smaller margins than sportsbooks.

See fair odds for a Kalshi contract →

What is vig, and how is it removed?

A fair two-outcome market has implied probabilities that add up to 100%. A bookmaker prices both sides a little worse, so the total comes to something like 104.8%. The extra 4.8% is the vig, also called overround or juice.

Multiplicative scales every outcome by the same factor, so the probabilities add to exactly 100%. It is the usual default. Additive subtracts the same amount from each outcome, which can push long shots to zero, so the calculator refuses it when that happens.

Why it matters for arbitrage

Comparing no-vig odds across venues shows which one is mispriced once the margin is stripped out. If the raw implied probabilities across venues sum to under 100%, the gap is a real arbitrage; see the arbitrage calculator.