Tool · Sports Betting · Conversion

Odds
converter.

Convert between decimal, fractional and American odds — and see implied probability for any price. The most-used betting tool in any serious bettor's toolkit, calibrated for South African decimal odds as the default.

Calculator

Convert any odds format

Type into any field — the others update automatically.

Enter odds in any format to see conversions

How to use this tool

Type the odds you have into whichever format you have them in — the converter recalculates the other two formats live as you type. The implied probability shown at the top is the percentage chance the bookmaker's price is suggesting for this outcome. That number is what you compare against your own estimate to identify value bets.

South African online bookmakers use decimal odds exclusively, so the decimal field is where most SA bettors will start. Convert to American or fractional when reading international betting analysis or comparing odds at international sites.

Quick reference: common conversions

DecimalFractionalAmericanImplied %
1.501/2−20066.67%
1.9110/11−11052.36%
2.001/1 (Evens)+10050.00%
2.503/2+15040.00%
3.002/1+20033.33%
5.004/1+40020.00%
11.0010/1+10009.09%
21.0020/1+20004.76%

The maths behind it

Every odds format is just a different display of the same underlying probability. The conversion formulas:

  • Decimal → Implied probability: 1 ÷ decimal × 100
  • Decimal → Fractional: decimal − 1, expressed as a fraction
  • Decimal → American (positive): (decimal − 1) × 100, when decimal ≥ 2.0
  • Decimal → American (negative): −100 ÷ (decimal − 1), when decimal < 2.0
  • Fractional → Decimal: (numerator ÷ denominator) + 1
  • American → Decimal (positive): (american ÷ 100) + 1
  • American → Decimal (negative): (100 ÷ |american|) + 1

Continue learning

Common Questions

You asked.

Decimal odds (used in SA, Europe and Australia) show your total return per Rand staked, including stake — odds of 2.50 return R2.50 per R1 bet. Fractional odds (UK tradition) show profit-to-stake — 5/2 means you win R5 for every R2 staked. American odds (US) use positive numbers showing profit on R100 (e.g. +250 means R250 profit on R100), or negative showing the stake required to win R100 (e.g. -150 means stake R150 to win R100). All three formats describe the same probability — they just present it differently.

Implied probability is the percentage chance the bookmaker's odds suggest. Calculated as 1 ÷ decimal odds × 100. Odds of 2.00 imply 50%, odds of 4.00 imply 25%, odds of 1.50 imply 66.7%. The sum of implied probabilities across all outcomes in a market exceeds 100% — that excess is the bookmaker's margin, also called the overround or vig.

Decimal odds are the SA standard, used by Hollywoodbets, Betway, Sportingbet, Supabets and every other SA-licensed operator. Most SA players never need fractional or American formats. The converter is most useful when comparing odds across international sites or reading betting analysis written for UK/US markets.

Two reasons. First, comparing odds across bookmakers — even if both display decimal, you understand prices faster when you can quickly cross-reference probability. Second, understanding what bookmakers are actually saying — converting 2.50 to '40% implied probability' tells you the bookmaker thinks this outcome happens 4 times in 10. That framing is much more useful for finding value than staring at decimals.