How We Calculate Our Data-Driven Ratings
Not expert opinion — metrics computed from 1.3M+ real odds records across 25 bookmakers. Margin, best-price frequency, and value vs fair price. Recalculated every night.
Ratings from real data, not opinion
Most bookmaker comparison sites rank operators based on editorial judgment or paid placement. Our data-driven ratings are different: they are computed entirely from a structured database of historical odds.
Formula-based, not subjective
Each metric follows a documented mathematical formula applied uniformly to every bookmaker in the dataset. No editorial discretion, no weighting adjustments.
Full transparency
The formulas, data sources, and update schedule are all disclosed on this page. You can verify the methodology independently using publicly available odds data.
Daily recalculation
Ratings use a rolling 365-day window, recalculated every night. Changes in a bookmaker's pricing behaviour are reflected quickly — not locked in from a one-time review.
Lowest Margin (Overround)
How much of every £1 staked does the bookmaker keep — on average?
For every betting market, we calculate the implied probabilities for all outcomes by taking the reciprocal of each decimal odd (1 ÷ odd). On a fair market these would sum to exactly 1.00 (100%). In practice, they always sum to more — the excess is the margin.
We measure this across three core markets per match: 1X2 (match result), Over/Under 2.5 goals, and Both Teams To Score (BTTS). The margin is then averaged across all available fixtures in the trailing 365-day window.
Overround Formula
Margin = (1/odd₁ + 1/odd₂ + … − 1) × 100
Applied to 1X2, Over/Under 2.5, and BTTS markets · averaged across 2,245 matches
Example
A market leader with average margin ~3.5% keeps 3.5p per £1 turnover. A soft bookmaker at 7% keeps twice as much — meaning your payouts are materially lower over time.
Key points
- Lower margin = higher expected payouts for the bettor
- Calculated fresh every 24 hours from live odds data
- Averaged across 1X2, O/U 2.5, and BTTS to avoid single-market bias
- Outliers (suspended markets, data gaps) are excluded from the sample
Our margin tracker ranks every tracked bookmaker by how little they bake into their prices — the lower the overround, the more of your stake is returned over time. The live table is recalculated nightly from the full odds dataset.
See the full Lowest-Margin rankingBest Odds / Highest Payout
How often does this bookmaker offer the single best price in the market?
For each match outcome in our dataset, we identify the highest available price across all 25 tracked bookmakers at the time of recording. A bookmaker earns a "best price" credit whenever its odds match or exceed this peak.
The Best Price % shows what share of all outcomes (across every tracked match) a given bookmaker led the market on. The Average Payout score shows the mean ratio of that bookmaker's odds to the best available price across outcomes — expressed as a percentage.
Best Price %
Best Price % = (outcomes where BK = market best) ÷ (total outcomes) × 100
Computed per outcome (Home / Draw / Away / Over / Under / BTTS-Yes / BTTS-No)
What it means
A bookmaker with 35% Best Price % leads the market on more than a third of all recorded outcomes — this is a strong signal that it consistently offers sharper-than-average prices.
Key points
- Outcome-level comparison, not just headline odds
- Covers 1X2, Over/Under, and BTTS markets for balanced coverage
- Higher Best Price % = more occasions where you get the best price without shopping around
- Average Payout % quantifies how close to the market peak this bookmaker's prices typically sit
We measure how often each bookmaker posts the single best price in the market, and how close its average price sits to the market peak. See which operators most consistently lead on price in the live ranking.
See the full Best-Odds rankingBest Value vs Fair Price
How close is this bookmaker's price to the true probability of the outcome?
A "fair" price is one where the implied probability exactly matches the true probability — no bookmaker margin included. To estimate fair probabilities, we use the no-vig lines from the two sharpest books in our dataset: Pinnacle and Betfair Exchange. We strip their margins using the standard multiplicative method (dividing each implied probability by the total overround), leaving a no-vig probability that acts as our best estimate of the true outcome probability.
We then compare every bookmaker's price against this fair benchmark and express the difference as a percentage (EV%). Because all bookmakers apply a margin, this number is negative for every operator in our sample. That is expected and honest — no commercial bookmaker offers positive EV in aggregate. The closer the number is to zero, the less value is being extracted from the bettor.
EV% Formula
EV% = (BK implied prob ÷ fair prob − 1) × 100
Fair probability derived from Pinnacle + Betfair Exchange no-vig line
Important: why all values are negative
A result of −3.1% means this bookmaker's price implies a probability 3.1 percentage points higher than the fair line — the margin taken from the bettor. A value of −1.8% is better for you than −5.4%. Closer to zero = less margin being charged. No bookmaker should show a positive figure in this column: if one does, re-check the data.
Key points
- Fair probability benchmark from Pinnacle and Betfair Exchange (lowest-margin sharp books)
- Negative values are normal and expected — the closer to 0%, the better for the bettor
- Pinnacle and Betfair themselves also appear in the table for transparency, despite negative EV
- Gives a market-relative measure independent of absolute odds level
Every bookmaker is scored against a no-vig fair line derived from the sharpest books, so you can see who extracts the least margin per bet — the closer to zero, the better the value. Full figures sit in the live ranking.
See the full Best-Value rankingHow We Rate Asian Handicap Odds
A two-way market with bookmaker-specific main lines — margin, best price, and value all need a slightly different lens.
Asian handicap markets are two-way: Home wins or Away wins, with no draw outcome possible. That single difference changes the overround calculation fundamentally. Instead of summing three implied probabilities as in 1X2 pricing, we sum only the Home and Away implied probabilities and subtract 1. The result is the two-way overround — typically a smaller absolute figure than 1X2, reflecting the simpler market structure.
Every bookmaker sets its own main handicap line by choosing the spread where Home and Away prices sit closest to equal money. Because these main lines differ between operators — one book might quote −0.5, another −1.0 on the same fixture — a direct margin comparison only makes sense on each bookmaker's own line. Forcing a single universal line across all operators would introduce an artificial distortion. Our margin figure is therefore calculated from each bookmaker's individually chosen main line.
Best price follows the same logic: for each handicap line in our dataset, we find the highest available price across all bookmakers quoting that same line. A bookmaker earns a best-price credit when its price matches or exceeds that market peak on its own line.
Value against a sharp reference — Pinnacle, or Betfair Exchange when Pinnacle's line is unavailable — applies a stricter rule. Comparison is only made when the reference book quotes the exact same handicap line as the bookmaker being measured. Where no line match exists for a given fixture, no value score is awarded for that fixture. This apple-to-apple constraint means the value sample for Asian handicap may be smaller than for 1X2 or Over/Under, but the comparisons that do appear are genuinely like-for-like. Pinnacle is excluded from its own reference comparison.
Two-Way Overround Formula
Margin = (1/home_odd + 1/away_odd − 1) × 100
Applied to each bookmaker's own main handicap line · no draw term included
Value calculation: line-matching rule
Value vs sharp is only calculated for fixtures where the reference book (Pinnacle or Betfair Exchange) quotes the identical handicap line as the bookmaker under review. When no matching line exists the fixture is excluded from the value score — ensuring no cross-line approximations enter the comparison. This means the effective sample size for the value metric may differ from the margin and best-price samples.
Key points
- Two-way market — overround calculated from Home and Away only, no draw term
- Each bookmaker's own main line is used for margin calculation
- Best price compares bookmakers quoting the same handicap line on a given fixture
- Value score only awarded when the sharp reference quotes an identical line
- Pinnacle serves as primary reference; Betfair Exchange is used when Pinnacle lacks coverage
- Pinnacle is excluded from comparing itself against the sharp reference
The live Asian Handicap margin ranking applies this methodology across all tracked bookmakers, recalculated nightly from the full odds dataset.
Compare Asian Handicap margins across all bookmakersWe show all bookmakers — not just our partners
Completeness matters as much as methodology. A dataset that omits inconvenient operators distorts every metric.
All 25 bookmakers included — with or without affiliate deals
Pinnacle is tracked in our dataset despite not being available for affiliate sign-ups in all markets. It appears in the Margin and Value comparisons because it sets the sharpest line and serves as one of the two fair-price benchmarks. Excluding it would make every other bookmaker look better than it really is.
- All 25 tracked bookmakers shown in the comparison table
- Pinnacle and Betfair Exchange included as sharp-book benchmarks
- Operator order in the table determined by metric, not by commercial relationship
- No paid placements in the data-driven rating columns
Affiliate disclosure
365BettingTips earns affiliate commissions from some bookmakers listed on this site. These commissions fund our editorial and data infrastructure. They do not influence the margin, best-odds, or value calculations in any way — the formulas are applied identically to every operator.
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Key terms explained
Definitions used consistently throughout our ratings. Understanding these makes the metric tables easier to interpret.
Market maker / Sharp book
A bookmaker that sets its own odds lines based on in-house models and accepts all bet sizes. Examples: Pinnacle, Betfair Exchange. These books typically have the lowest margins and are used as the fair-price benchmark in our Value metric.
Soft book
A bookmaker that follows the sharp market rather than setting it. Soft books may limit winning bettors, offer higher marketing bonuses, and generally carry higher margins to protect their position.
Overround / Vig / Margin
The amount by which the sum of implied probabilities across a market exceeds 100%. A 5% overround means the bookmaker extracts 5% of every unit of stake over a large sample. Also called "juice" or "vig" in American betting parlance.
No-vig line
A theoretical odds line where the margin has been mathematically removed, leaving implied probabilities that sum to exactly 100%. Used as a proxy for the true outcome probability.
Steam move
A rapid, coordinated shift in the betting market, typically caused by sharp money hitting multiple books simultaneously. Steam moves reflect new information entering the market and are a property of a market event — not a characteristic of a specific bookmaker.
Implied probability
The probability implied by a set of odds: 1 ÷ decimal odd. For odds of 2.50, the implied probability is 40%. If you sum implied probabilities across all outcomes and get more than 100%, the excess is the margin.
How and when ratings are refreshed
Data-driven metrics become stale quickly if not maintained. Here is our schedule.
Odds collection
Our crawler collects odds from all 25 bookmakers continuously. Pre-match prices are captured from line-open through to kick-off for every tracked fixture.
Metric recalculation
Margin, Best Odds %, and Value vs Fair Price are all recalculated from scratch each night using the rolling 365-day window. Results are published by early morning.
Data window
Each recalculation uses the 2,245 most recent matches in the 12-month lookback. This balances recency (recent pricing behaviour matters more) with sample size (stability).
Frequently asked questions
Beyond the Numbers: Our Editorial Rating
Data-driven metrics tell you who offers the best odds, lowest margins, and strongest value. But bookmaker quality goes beyond price. Our overall rating methodology evaluates 6 pillars — licensing reliability, odds quality, market depth, bonus value, live betting platform, and independent editorial review — to produce a holistic score out of 10.
Read Rating Methodology →See the Ratings in Action
Browse our full bookmaker comparison table — Margin, Best Odds %, and Value vs Fair Price calculated from 1.3M+ real odds records.