CAPTRACKER · ODDS TOOLS
ODDS CONVERTER
American, decimal, and fractional odds — plus the implied probability behind them, and a no-vig calculator to strip the book’s margin and see the true price.

Convert the odds

ONE PRICE, EVERY FORMAT
American
Decimal
Fractional
Implied Prob
Type an American or decimal price above — every other format updates live.

Strip the vig · fair odds

NO-VIG FAIR VALUE

Enter both sides of a market. We remove the book’s built-in margin (the vig) and show what each side’s price would be if the book took no cut — the fair line to measure any pick against.

SIDE A — FAIR
Implied (with vig)
Fair probability
Fair odds
SIDE B — FAIR
Implied (with vig)
Fair probability
Fair odds
Book hold (vig):
WHY NO-VIG MATTERS

The no-vig fair price is the honest coin-flip line hiding underneath the book’s margin. It’s the same first step CapTracker’s model takes before deciding whether a capper’s pick actually beats the market: convert the quoted odds to a probability, strip the vig, and compare. If a pick’s edge disappears once the vig is gone, it was never really an edge.

How odds formats work

American odds are anchored to $100. A minus number (−150) is the favorite — it’s how much you stake to win $100. A plus number (+200) is the underdog — how much you win on a $100 stake. Decimal odds show the total return per $1 staked, stake included (1.67 means $1 comes back as $1.67). Fractional odds (common in the UK) show profit over stake as a ratio (2/1 = win $2 per $1).

AmericanDecimalFractionalImplied Prob
−2001.501/266.7%
−1101.9110/1152.4%
+1002.001/150.0%
+1502.503/240.0%
+2503.505/228.6%

Implied probability & the vig

Implied probability is the win rate the odds are quietly assuming. Convert both sides of a market and add them up: a fair, no-margin market totals 100%. A real one totals more than 100% — that overage is the vig (also called juice or hold), the book’s built-in edge. Two sides at −110 imply 52.4% each = 104.8%, so the vig is about 4.8%. Strip it back to 100% and each fair side sits at 50%. For the deeper walk-through, see how betting odds imply probability and the betting glossary.

Common questions

How do you convert American odds to decimal?
For a positive price: decimal = (American / 100) + 1, so +200 → 3.00. For a negative price: decimal = (100 / |American|) + 1, so −150 → 1.67.
What is implied probability?
It’s the break-even win rate baked into the odds. From decimal odds it’s simply 1 / decimal. −110 (1.91) implies about 52.4% — you’d need to win more than that to profit long-term.
What does “no-vig” or “removing the vig” mean?
Both sides’ implied probabilities add up to more than 100% because the book takes a cut. No-vig rescales them back to 100%, giving each side’s fair probability and fair price — the true line to compare any bet against.
Is this odds converter free?
Yes — it runs entirely in your browser, no account needed. CapTracker is a sports-analytics tool; it doesn’t take bets or touch your money.
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