How do I convert American odds to decimal?

For positive American odds, decimal = (odds / 100) + 1. For negative odds, decimal = (100 / |odds|) + 1. So -110 becomes 1.91 and +150 becomes 2.50. Use the Odds Converter above to do it instantly in any format.

What are no-vig (fair) odds?

Sportsbooks add a margin (the vig) to both sides of a market, so the implied probabilities sum to more than 100%. No-vig odds remove that margin to reveal the market's true implied probability and the fair price you should be beating.

What is the Kelly Criterion in betting?

The Kelly Criterion returns the fraction of your bankroll to stake that maximizes long-run growth, given your true win probability and the offered odds. Many bettors use a half- or quarter-Kelly stake to reduce variance.

The Verdexed Toolkit

Bet the math, not the hype

The same quantitative engine behind our predictions, distilled into free tools every serious bettor should run before they click place bet. Convert any price, strip out the book's vig to find the true number, size your stake with Kelly, and price any parlay — in seconds, no signup.

Odds Converter

Convert any price into American, decimal, fractional, and the implied probability (the win rate you must beat to profit).

Odds

Input format

American-110

Decimal1.909

Fractional10/11

Implied probability52.38%

Break-even win rate52.4%

No-Vig Fair Odds

Books bake a margin ("the vig") into both sides. Strip it out to see the market's true implied probability and the fair price — the number sharp bettors actually shop against.

Side A odds

Side B odds

A fair probability

54.3%

B fair probability

45.7%

A fair odds

-119

B fair odds

+119

Bookmaker hold (the house edge on this market)3.98%

Parlay Calculator

Combine legs to see the true parlay price, payout, and the (often sobering) implied probability the whole ticket cashes.

Leg 1

Leg 2

Leg 3

Stake ($)

Parlay odds

+811

Decimal

9.11

To win

$811.16

Total payout

$911.16

Implied win chance

10.98%

Kelly Stake Calculator

Given your true win probability and the offered price, Kelly returns the bankroll fraction that maximizes long-run growth. Most pros bet a fraction of it — full Kelly is volatile.

Odds (American)

Your win %

Bankroll ($)

Kelly fraction

8.3%

Edge (EV per $1)

+$0.100

Full Kelly stake

$83.33

Half Kelly (recommended)

$41.67

Quarter Kelly (conservative)

$20.83

Closing Line Value Calculator

Compare the price you got to where the line closed. Consistently beating the close (positive CLV) is the clearest sign you're a long-term winner.

Your odds

Closing odds

Your implied prob

40.0%

Closing implied prob

45.5%

You beat the close ✓+13.64% CLV

The line moved 5.5 points toward your side after you bet. Over a large sample, positive CLV is what separates winners from the field.

Why these tools matter

Winning bettors don't guess — they price everything. Every line a sportsbook posts carries a hidden margin, and every payout hides an implied probability you have to beat to profit. These calculators surface those numbers instantly so you always know whether a price is fair before you take it.

They're powered by the same odds math that runs under Verdexed's model, which grades every game across the four major leagues and flags where our projection disagrees with the market. Once you've found a fair price here, see where the engine sees an actual edge.

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