How Betting Odds Work — Decimal, American & Fractional (Canada)

Decimal odds (e.g. 2.50) are the default at PROLINE+, PlayNow, BetMGM Canada, FanDuel Canada and every European-facing sportsbook. The number is your total return per $1 staked — so a $10 bet at 2.50 returns $25 ($15 profit + $10 stake back). One number, no mental gymnastics.

American odds (+150 / −120) come from US sportsbooks and are still common on hockey and NFL markets. Positive odds show profit on a $100 stake (+150 → $150 profit). Negative odds show what you'd need to stake to win $100 (−120 → risk $120 to win $100).

Fractional odds (3/2, 7/4) are the British format and dominate horse-racing markets. The numerator is profit, the denominator is stake — 3/2 means $3 profit per $2 staked.

Decimal → American: if decimal ≥ 2.00, American = (decimal − 1) × 100. If decimal < 2.00, American = −100 / (decimal − 1). Example: 2.50 → +150. 1.83 → −120.

American → decimal: positive American → (odds / 100) + 1. Negative American → (100 / |odds|) + 1.

Fractional → decimal: (numerator / denominator) + 1. 3/2 → 2.50.

The Daily Stash betting odds calculator does every conversion in real time — you don't need to memorise the formulas, but understanding them is what separates a casual punter from someone reading lines critically.

Implied probability is the chance the odds suggest. The formula is simple: 1 / decimal odds × 100. Odds of 2.00 imply 50%. Odds of 1.50 imply 66.7%. Odds of 4.00 imply 25%.

Here's the catch: on a two-way market (e.g. Heads vs Tails), the implied probabilities add up to more than 100%. That overround is the sportsbook's margin — the vig or juice. A typical Canadian sportsbook bakes in 4-6% on major-league moneylines, 8-12% on player props.

To find true odds, divide each implied probability by the total overround. If a coin flip is priced 1.91 / 1.91, both sides imply 52.4%, total 104.8%. True odds are 50/50; the 4.8% gap is the book's edge before any bet is placed.

Multiply every leg's decimal odds together, then multiply the result by your stake. A 3-leg parlay at 2.00 × 1.80 × 2.50 = combined odds of 9.00. A $10 stake returns $90 ($80 profit).

Parlays look generous because the payout compounds — but so does the probability of losing. Each leg's vig also compounds, so a 4-leg parlay of six-percent-juice moneylines is usually a 26-28% house edge bet. The Daily Stash parlay calculator surfaces the combined implied probability so you can see exactly how unlikely a payout is before you place it.

One losing leg kills the entire ticket. Same-game parlays (SGPs) correlate legs deliberately — the book re-prices them, often at much worse than the multiplied odds would suggest. Always compare the SGP price to what you'd get building the same legs as a regular parlay across two books.

Closing-line value is the gap between the odds you got and the odds at kickoff. If you bet a team at 2.10 and the line closes at 1.95, you beat the closing line by 7.7% — a positive CLV signal that you spotted something the market eventually agreed with.

CLV over hundreds of bets is the only public, transparent way to measure betting skill. Short-term win rate is mostly variance; CLV survives small samples. Professionals track it religiously, and recreational bettors who track it usually discover they aren't beating the closing line — at which point quitting saves real money.

Outside Ontario, single-event sports betting runs through provincial sportsbooks: PROLINE+ (Ontario also has it, plus the open market), PlayNow (BC, Manitoba, Saskatchewan), Mise-O-Jeu+ (Quebec), and Atlantic Lottery (NS, NB, PE, NL). Lines are typically wider (more vig) than the Ontario private operators.

Comparing prices matters. Even a 0.05 decimal-odds difference (e.g. 1.95 vs 1.90 on a coin-flip market) cuts the house edge roughly in half. Bookmark two or three sportsbooks and check both before every bet.

Set a session budget before you load the calculator. Run the math, place the bet, walk away from the app for an hour. If you find yourself opening the calculator at 1am on a Tuesday, that's the signal to use deposit limits or take a 7-day cool-off — every Canadian sportsbook is legally required to offer both.