Fractional, Decimal and American Ice Hockey Odds

Converting Fractional Odds for UK Hockey Bettors

I was at a small bar in Edinburgh during the 2020 lockdown easing, half-watching a Tampa Bay versus Dallas Cup final game, when the chap next to me asked what 13/8 paid on a tenner. He had been a punter for thirty years. He had never converted a fractional price in his head in his life, because the bookies always did it for him at the counter. The migration to online and decimal pricing had left him stranded. I worked it out — £16.25 plus stake, £26.25 back — and we both went back to the hockey. The encounter stuck with me. UK punters straddle three odds formats and most know one of them well, one of them poorly, and one of them not at all.

This is the conversion guide I wish that bloke had had on his phone.

The three formats and where they come from

Fractional odds are the British tradition. A 5/1 price means you win five pounds for every one staked, plus your stake back. They are the format of betting shops, the racing post and high-street tradition. They make the profit easy to read at the cost of obscuring the implied probability.

Decimal odds are the European and modern UK online standard. The price includes the stake — decimal 6.00 returns six pounds total for every pound staked, of which five is profit and one is the original stake. Decimal is the format used by most NHL traders, by every quantitative betting tool, and by Pinnacle and the European exchanges. It is the format that lets you calculate implied probability in your head.

American odds are the format of every US sportsbook and most NHL-focused analysis written for an American audience. A favourite is priced with a minus sign — -150 means you stake $150 to win $100. An underdog is priced with a plus — +130 means you stake $100 to win $130. American odds make sense once you internalise the convention, but they are awkward for UK punters reading mixed sources.

“In the UK, both fractional and decimal odds formats appear at licensed operators, with most modern apps offering a toggle in account settings.” That toggle exists because the UK market sits between two traditions — the high-street fractional past and the data-driven decimal present.

Fractional to decimal in your head

The conversion that matters most is fractional to decimal, because most online tools and analysis articles run in decimal. The formula is straightforward: divide the numerator by the denominator and add one. 5/1 becomes 6.00. 7/2 becomes 4.50. 13/8 becomes 2.625. 2/5 — an odds-on favourite — becomes 1.40.

The mental shortcut for the common UK fractional prices: 1/1 (evens) is decimal 2.00, 6/4 is 2.50, 2/1 is 3.00, 5/2 is 3.50, 3/1 is 4.00, 9/2 is 5.50, 5/1 is 6.00. Knowing those seven by heart covers eighty per cent of what UK punters see at the high street.

The hockey-specific quirk is that NHL moneylines on UK books are often offered in 1/8 fractional increments — 4/5, 6/5, 7/5, 11/10, 23/20 — that look fiddlier than the racing-style halves and quarters. Decimal makes them legible: 4/5 is 1.80, 11/10 is 2.10, 23/20 is 2.15. The same prices in fractional form look harder than they are.

American to decimal for cross-Atlantic reading

If you read US-based NHL analysis, you will see American odds. The conversion from American to decimal goes two ways depending on the sign.

For minus prices (favourites): decimal = (100 / |American|) + 1. So -150 becomes (100 / 150) + 1 = 1.667. -110 becomes 1.909. -200 becomes 1.50. -130 becomes 1.769.

For plus prices (underdogs): decimal = (American / 100) + 1. So +150 becomes 2.50. +110 becomes 2.10. +200 becomes 3.00. +130 becomes 2.30.

The standard US juice line of -110 / -110 — the equivalent of a UK 10/11 / 10/11 — is decimal 1.909 each side. The 4.5 % overround is built directly into the price. UK punters seeing decimal 1.909 quoted on a near-even moneyline should recognise it instantly as the American standard juice imported.

Implied probability in each format

Decimal odds make implied probability a one-step calculation: 1 divided by the decimal price. 2.00 implies 50 %. 1.50 implies 66.7 %. 3.00 implies 33.3 %. That single equation is the reason most professionals use decimal exclusively.

Fractional odds require a slightly more awkward formula: denominator divided by sum of numerator and denominator. 5/1 implies 1 / (5+1) = 16.7 %. 7/2 implies 2 / (7+2) = 22.2 %. 4/5 implies 5 / (4+5) = 55.6 %. The numbers are fine once you do them, but the format slows you down compared to decimal.

American odds have two formulas. Negative prices: |American| / (|American| + 100). -150 implies 150 / 250 = 60 %. Plus prices: 100 / (American + 100). +150 implies 100 / 250 = 40 %. The bifurcated formula is the part that catches UK punters who learn the convention from American-published material.

Implied probability is the gateway to everything sharper. Devigging, expected value, Kelly sizing, closing line value — all of them sit on top of a clean conversion from price to probability. Whichever format you use, doing that conversion fluently is the prerequisite skill.

Why the format you bet in matters

Most UK operators let you toggle the display format in your account settings. Bet365, William Hill, Paddy Power, Ladbrokes, Betfair Sportsbook and Sky Bet all support fractional and decimal as a minimum, with American available on a handful of operators that cater to US-sport bettors. Bet365 is the largest single UK sports betting brand and the typical default for newcomers — the toggle sits inside account preferences.

My standing recommendation, and what I do myself, is to use decimal for everything. The cognitive load of converting fractional in your head while comparing prices across three books in real time during a hockey game is unnecessary friction. Decimal lets you read implied probability in a glance, compare prices across sources without conversion, and integrate with every spreadsheet or tracking tool worth using.

If you have grown up on fractional and prefer the feel of it, by all means stay there for high-street, racing and the bets you place casually. For NHL specifically — where you are likely reading at least some US-published analysis, comparing prices to sharp books, and tracking edge over time — decimal will save you more time than any other single tweak to your workflow.

A side-by-side cheat sheet

For the prices you see most often in NHL markets, here are the three formats side by side. Decimal 1.50 is fractional 1/2 is American -200. Decimal 1.80 is 4/5 is -125. Decimal 1.91 is 10/11 is -110. Decimal 2.00 is evens is +100. Decimal 2.10 is 11/10 is +110. Decimal 2.50 is 6/4 is +150. Decimal 3.00 is 2/1 is +200. Decimal 4.00 is 3/1 is +300. Decimal 6.00 is 5/1 is +500.

Print it, save it as a phone wallpaper, or just bookmark this paragraph. After a season of looking at NHL prices, the conversions become automatic. The first month is awkward. The second month is fluent. By the third month you are reading implied probability off decimal odds without consciously calculating it, and the question “what does 13/8 pay” no longer needs a phone calculator.

What I would tell my younger self about formats

Pick one format and stick with it. Toggle your account preferences once and never touch them again. The bettors who flip back and forth between fractional and decimal — depending on which feels more comfortable for that particular bet — are the ones who make small but systematic errors. Consistency in how you read prices is consistency in how you evaluate edge.

And learn the implied probability conversion in your chosen format by heart. Whatever else you skip — Kelly sizing, devigging, line-shopping — the one-step conversion from price to probability is non-negotiable. It is the foundation everything else rests on.

The natural next step once the prices are legible is reading what the book actually thinks underneath them — the implied probability and devigging guide covers exactly that.

Written by the editors at Ice Hockey Betting Tips.