What is vig (vigorish) in sports betting?

Vig — short for vigorish, also called juice or overround — is the margin a sportsbook builds into its odds. It's the difference between the true probability of an outcome and what the odds imply. Lower vig means you keep more of your winnings on every bet. For example, a standard -110/-110 line has about 4.76% vig.

How often is this data updated?

We pull fresh odds from The Odds API three times per day — at 6:00 AM, 2:00 PM, and 10:00 PM UTC. Each snapshot captures the latest lines from every sportsbook that has posted odds. The timestamp at the top of the page shows the most recent refresh.

How is the vig grade calculated?

Each sportsbook is graded on a letter scale based on average vig: A+ (under 2%) is exceptional, A (2–3%) is excellent, B+ (3–4%) is above average, B (4–5%) is the industry standard, C (5–6%) is below average, and D (above 6%) indicates high-juice markets.

Why does lower vig matter for bettors?

Lower vig directly impacts your long-term returns. A bettor placing $1,000 per week at a book with 4% vig loses roughly $40/week to the house edge. At 2% vig, that drops to $20/week — a $1,040 difference over a year. For serious bettors, shopping for lower vig is one of the most reliable ways to improve profitability.

What sportsbooks do you track?

We track both regulated US sportsbooks (DraftKings, FanDuel, BetMGM, Caesars) and offshore books (Bovada, BetOnline, MyBookie, BetUS, LowVig.ag, BetAnySports). Data comes from The Odds API, which aggregates real-time lines from licensed sources.

Best WTA Madrid Open Odds Today

Q: Can I still compare sportsbooks for WTA Madrid Open?

No live odds are currently available for WTA Madrid Open. In the meantime, check out our odds comparison page for other available options, or visit our overall Vig Index for cross-sport rankings.

WTA Madrid Open Odds Not Currently Available

WTA Madrid Open does not currently have odds in our data feed. When odds for events are available at sportsbooks they will be listed here. This page updates 3× daily from The Odds API — when sportsbooks begin posting WTA Madrid Open lines, the full analysis will become available.

In the meantime, check out our odds comparison page for other available options.

The WTA Madrid Open operates within a highly compressed tournament window, typically running from late April to early May each year as part of the clay court season leading up to the French Open. Unlike traditional sports leagues, tennis tournaments don't have extended seasons or playoffs—the Madrid Open concludes within a single week. Preseason odds for the tournament generally appear 2-3 months prior in February and March, with early outright winner markets opening as players begin their clay court preparation in South American tournaments. The unique scheduling means bettors have a narrow window to capitalize on value before the field is finalized.

Off-season betting opportunities for Madrid center heavily on outright tournament winner futures, with books offering odds on both WTA 1000-level champions and specific surface specialists who excel on clay. Set betting markets and first-round matchup props become available once the draw is released, typically 4-5 days before play begins. The tournament's mandatory participation requirements for top-ranked players create different dynamics than smaller events—injury withdrawals and late entry decisions by returning players significantly impact odds. Head-to-head season series betting between frequent clay court rivals like Swiatek and Sabalenka often provides value during the off-season months.

Vig patterns in Madrid betting show the tightest margins on outright winner markets for top-4 seeds, with books maintaining 6-8% holds on favorites. The best value window typically emerges in March when early clay court results begin filtering in but before the full European swing establishes form lines. Historically, the biggest odds movements stem from late injury announcements—particularly back and shoulder issues that flare up during the transition from hard courts to clay. Coaching changes during the off-season, especially for Spanish players who receive home crowd support, can shift odds by 15-20% when announced. Weather delays and court condition reports also create live betting opportunities that savvy bettors monitor closely during tournament week.

In-Season Sports

These sports have active odds right now:

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How We Calculate These Numbers

Data Source: All odds on this page come from The Odds API, which aggregates real-time lines from licensed US and offshore sportsbooks. We track moneyline, spread, and totals markets across every sport with active betting lines.
Update Frequency: We pull a fresh snapshot of every tracked market three times per day — at 6:00 AM, 2:00 PM, and 10:00 PM UTC. Each snapshot captures the latest lines from every sportsbook that has posted odds for a given event. The timestamp at the top of each page tells you exactly when the data was last refreshed.
Vig Calculation: Vig (short for vigorish, also called juice or overround) measures the margin a sportsbook builds into its odds. We calculate it by converting the odds on each side of a market to implied probabilities, summing those probabilities, and subtracting 100%. For example, a market priced at -110/-110 implies 52.38% on each side — a total of 104.76%, meaning a vig of 4.76%. Lower vig means better value for bettors because you keep more of your winnings.
Per-Market Breakdown: We compute vig separately for each market type: moneyline (h2h), point spreads, and totals (over/under). The "average vig" shown for each sportsbook is the mean across all market types weighted by the number of events sampled in each market.
Grading Scale: Every sportsbook receives a letter grade based on its average vig: A+ (under 2%) is exchange-level pricing. A (2–3%) is very competitive. B+ (3–4%) is above average. B (4–5%) is the industry standard — a -110/-110 line is 4.76%. C+ (5–6%) is slightly below average. C (6–7%) is below average. D (7–8%) is high vig. D− (8–10%) is very high vig. F (10%+) is predatory pricing. See the full Vig Index Methodology for formulas, worked examples, and known limitations.
Trend Tracking: We store daily snapshots for 30 days, allowing us to show 24-hour and 7-day vig trends. A downward trend (improving) means sportsbooks are tightening their lines — often in response to increased competition or higher betting volume as a season heats up.