UK & Ireland Odds Decoded: Fractional vs Decimal, Each-Way Math, and Market Moves

Odds formats (quick conversions)

• Fractional → Decimal: Dec = (Num/Den) + 1
  Example: 5/2 → 3.5

• Decimal → Fractional (rule of thumb): subtract 1, express as a simple fraction
  Example: 2.20 → 1.20 ≈ 6/5

• Implied probability:

  • Fractional: Imp% = Den / (Num + Den)
    5/2 → 2 / (5+2) = 28.57%

  • Decimal: Imp% = 1 / Dec
    3.50 → 1/3.50 = 28.57%

Overround (book margin)

For a market with outcomes p1…pn, convert each price to implied % and add them.

• Example (three outcomes): 43% + 31% + 30% = 104% → ~4% book margin.
  Lower totals (closer to 100%) = sharper market for you.

Each-way (EW) essentials (horse racing)

An EW bet is two bets: win and place.

• Place terms: shown as a fraction of the win odds (e.g., 1/5) and number of places (e.g., 1–4).

• Payouts (example): 10/1 (11.0 dec), 1/5 odds, 1–4 places, 1pt EW (2pts total).

  • Horse wins: Win returns = 1pt × 10/1; Place returns = 1pt × (10/1 × 1/5 = 2/1).

  • Horse places (no win): Only the place part pays at 2/1.

• When EW helps: bigger fields, generous place terms, horses with consistent placing profiles.

• When to go win-only: shorter prices (≤ 6/1) or stingy place terms.

Rule 4 (deductions)

If a horse is withdrawn after you bet, winnings can be reduced by a set pence-in-the-pound scale tied to the withdrawn horse’s price. Always check your book’s Rule 4 table before race time.

Football (soccer) markets: UK/IE basics

• Asian Handicaps (AH): quarter-ball lines (e.g., −0.25/ +0.25) split stakes; draws can refund half.

• Totals (goal lines): 2.25/2.75 split stakes between 2.0 and 2.5 (or 2.5 and 3.0).

• Cards & corners: highly ref/tempo dependent—know venue, weather, and referee profile.

• Team news cadence: England announcements closer to kickoff; in Ireland, late lineup info can move totals quickly.

Market moves (what they often mean)

• Shortening price (drift-in): demand, positive news, or reduced field strength (racing).

• Drift (price lengthens): lack of interest, negative signals, or ground going against a running style.

• Going changes (racing): Soft/Heavy boosts stamina types; Good-to-Firm favours speed/on-pace.

• Weather (football): strong wind suppresses crosses/long shots → totals can tick down.

Quick pre-bet checklist

•  Confirm place terms (racing), line rules (football), and Rule 4/NRNB/BOG policies

•  Convert your chosen price → implied %; compare across books

•  Note your skip price (discipline beats FOMO)

•  Log results by units and CLV (did your number beat the close?)

Educational content only—no tips on the blog. Bet responsibly.