How do I convert decimal odds to fractional?

Subtract 1 from the decimal odds, then convert the result to a fraction and simplify. Example: 2.50 − 1 = 1.50 = 3/2. So decimal 2.50 equals fractional 3/2.

How do I convert American odds to decimal?

For positive American odds: (American / 100) + 1. Example: +200 → 3.00. For negative American odds: (100 / |American|) + 1. Example: −150 → 1.667.

How do I calculate implied probability from odds?

Divide 1 by the decimal odds. Example: decimal 2.50 → 1 / 2.50 = 0.40 = 40% implied probability. Remember: bookmaker odds include a margin so implied probabilities from a market sum above 100%.

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Enter odds in any format — decimal, fractional, American, Hong Kong, Malay, or Indonesian — and instantly convert to all others plus implied probability and payout.

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Quick Reference Table

Decimal	Fractional	American	Implied %	£100 return
1.25	1/4	−400	80.00%	£125
1.50	1/2	−200	66.67%	£150
1.80	4/5	−125	55.56%	£180
2.00	Evens	±100	50.00%	£200
2.50	6/4	+150	40.00%	£250
3.00	2/1	+200	33.33%	£300
4.00	3/1	+300	25.00%	£400
6.00	5/1	+500	16.67%	£600
11.00	10/1	+1000	9.09%	£1,100

For in-depth format explanations, see all odds types or use the format-specific guides: decimal, American, fractional, Asian.

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