If you can't read odds properly, you're flying blind. Here's how decimal, fractional, and American odds actually work — with real rugby and cricket examples so you can spot value before placing a bet.
Odds tell you two things: how likely the bookie thinks something is to happen, and how much you'll get paid if you're right. Honestly, getting your head around odds is the single most useful thing you can do as a bettor. Everything else builds on this.
At their core, odds reflect probability. When a bookie sets odds on a rugby match, they're estimating the chances of each outcome based on form, history, injuries, conditions, and how the public is betting. Those probabilities then get turned into payout ratios - with the bookmaker's cut baked in (that's the "vig" or "overround").
Three main formats: decimal, fractional, and American (moneyline). In NZ, decimal is the standard - it's what you'll see by default at every sportsbook that takes Kiwi punters. But knowing all three is handy when you're comparing odds across platforms or reading international content. Most bookies on our best NZ betting sites list let you switch between formats in your settings.
Here's the fundamental rule: lower odds = higher probability and lower payout. Higher odds = lower probability and bigger payout. An All Blacks favourite at 1.30 is expected to win easily but pays bugger all profit. A 10.00 underdog is unlikely to get up, but if they do, the payout's massive.
Decimal odds are what you'll see everywhere in NZ, Australia, and Europe. They're the simplest format to understand - the number just tells you what you get back per dollar bet, including your original stake.
So if the All Blacks are at 1.45 to beat Australia, a $100 bet returns $145 ($100 stake + $45 profit). If the Wallabies are at 3.20, that same $100 returns $320 ($100 stake + $220 profit). Higher number = bigger payout = less likely to happen (according to the bookie).
Quick cheat sheet:
| Example Bet | Decimal Odds | $50 Stake Returns | Profit |
|---|---|---|---|
| All Blacks to beat Fiji | 1.12 | $56.00 | $6.00 |
| All Blacks to beat South Africa | 1.75 | $87.50 | $37.50 |
| Hurricanes to win Super Rugby | 4.50 | $225.00 | $175.00 |
| Black Caps to win Cricket World Cup | 12.00 | $600.00 | $550.00 |
Every NZ sportsbook we've tested - Rooster.bet, 22bet, Ivibet, the lot - defaults to decimal odds. That's what you'll see unless you go into settings and change it.
Fractional odds are the old-school UK and Ireland format. You'll still see them at some bookies and in horse racing coverage. They look like fractions - 5/1, 7/2, 1/4 - and they show your profit relative to your stake. Unlike decimal odds, they don't include your stake in the number.
At 5/1 ("five to one"), you win $5 for every $1 staked. So a $100 bet returns $600 total ($500 profit + $100 stake). At 1/4 ("four to one on"), you win $1 for every $4 staked - a $100 bet returns just $125 ($25 profit + $100 stake).
| Fractional Odds | Decimal Equivalent | $100 Stake Returns | Implied Probability |
|---|---|---|---|
| 1/10 | 1.10 | $110 | 90.9% |
| 1/4 | 1.25 | $125 | 80.0% |
| 1/2 | 1.50 | $150 | 66.7% |
| Evens (1/1) | 2.00 | $200 | 50.0% |
| 2/1 | 3.00 | $300 | 33.3% |
| 5/1 | 6.00 | $600 | 16.7% |
| 10/1 | 11.00 | $1,100 | 9.1% |
Most Kiwi punters won't use fractional odds day-to-day, but it's handy to know them for UK sports coverage or UK-based bookies. Just remember: fractional odds show profit only, not total return. If you prefer keeping things simple, stick with decimal and change the format in your settings if needed.
American odds (also called moneyline) are what you'll see in the US. They use plus (+) and minus (-) signs - minus for favourites, plus for underdogs. You won't need these often in NZ, but they pop up when you're betting on NBA, NFL, MLB, or reading US tipsters.
The minus number tells you how much you need to stake to win $100 profit. So -200 means you bet $200 to win $100 (total return $300). Bigger negative number = bigger favourite. All Blacks at -300 against Japan? Very strong favourite - you'd risk $300 to win $100.
The plus number shows how much profit you'd make from a $100 stake. So +250 means $100 returns $350 total ($250 profit + $100 stake). Bigger positive number = bigger underdog. Japan at +800 against the All Blacks? A $100 bet returns $900 if they pull off the upset.
| American Odds | Decimal Equivalent | Interpretation |
|---|---|---|
| -500 | 1.20 | Heavy favourite - bet $500 to win $100 |
| -200 | 1.50 | Clear favourite - bet $200 to win $100 |
| -110 | 1.91 | Slight favourite - bet $110 to win $100 |
| +100 | 2.00 | Even money - bet $100 to win $100 |
| +200 | 3.00 | Underdog - bet $100 to win $200 |
| +500 | 6.00 | Big underdog - bet $100 to win $500 |
| +1000 | 11.00 | Long shot - bet $100 to win $1,000 |
Our take: just use decimal odds for everyday betting and only worry about American odds when you're dealing with US sports or content. Every NZ sportsbook we recommend lets you switch formats with one click.
You probably won't need to convert manually very often, but knowing the formulas helps when you're reading international content or comparing odds across platforms with different defaults.
For favourites (decimal less than 2.00):
For underdogs (decimal 2.00 or greater):
| Decimal | Fractional | American | Implied Prob. |
|---|---|---|---|
| 1.10 | 1/10 | -1000 | 90.9% |
| 1.25 | 1/4 | -400 | 80.0% |
| 1.50 | 1/2 | -200 | 66.7% |
| 1.80 | 4/5 | -125 | 55.6% |
| 2.00 | 1/1 (Evens) | +100 | 50.0% |
| 2.50 | 6/4 | +150 | 40.0% |
| 3.00 | 2/1 | +200 | 33.3% |
| 4.00 | 3/1 | +300 | 25.0% |
| 5.00 | 4/1 | +400 | 20.0% |
| 10.00 | 9/1 | +900 | 10.0% |
| 21.00 | 20/1 | +2000 | 4.8% |
In reality, most NZ sportsbooks let you toggle your display preference in settings, and comparison sites normalise everything automatically. But understanding how the formats relate to each other makes you a sharper bettor overall.
This is where things get properly useful. Implied probability is the percentage chance of an outcome that's "implied" by the odds. Most punters skip right past this, which is a shame - it's how you figure out whether a bet is actually worth taking.
Say the All Blacks are at 1.45 to beat South Africa. That's (1 / 1.45) x 100 = 68.97% implied probability. The bookie reckons the ABs have about a 69% chance. Now, if YOU think they've actually got a 75% chance, that bet has value - the odds are better than the real probability.
But if you think they've only got a 60% chance? Then the odds don't offer value - the bookie's pricing them as more likely than you believe. This comparison between your assessment and the implied probability is genuinely the foundation of profitable long-term betting.
| Scenario | Typical Odds | Implied Probability |
|---|---|---|
| All Blacks vs Tier 2 nation | 1.05 - 1.15 | 87% - 95% |
| All Blacks vs South Africa | 1.40 - 1.80 | 56% - 71% |
| Even Super Rugby match | 1.85 - 2.00 | 50% - 54% |
| Black Caps Test match favourite | 1.60 - 2.20 | 45% - 63% |
| Super Rugby outright winner | 4.00 - 15.00 | 7% - 25% |
One thing to notice: if you add up the implied probabilities from a single market, they'll always total more than 100%. That extra bit is the bookmaker's margin - their built-in profit. More on that next.
Every bookie bakes a profit margin into their odds. It's called the "overround," "vig," or "juice" depending on who you're talking to. Basically, it's the gap between the true probability and what the odds imply. This is how bookies make money regardless of who wins.
For a two-way market (like a rugby match with no draw), just add up the implied probabilities of both outcomes:
All Blacks: 1.75 decimal odds = 57.14% implied probability
South Africa: 2.10 decimal odds = 47.62% implied probability
Total: 57.14% + 47.62% = 104.76%
Margin: 104.76% - 100% = 4.76%
This means for every $100 wagered across both outcomes, the bookmaker expects to keep roughly $4.76 in profit.
Lower margins = better value for you. The best offshore bookies available to NZ punters typically run 3-5% margins on major rugby and cricket markets. TAB NZ? Often 10-15% on the same events. That gap compounds over time into a massive difference in your returns.
| Sportsbook Type | Typical Margin | Impact on $100 Bet |
|---|---|---|
| Sharp bookmakers (Pinnacle) | 2-3% | $2-3 less than true odds |
| Top offshore (Rooster.bet, 22bet) | 3-5% | $3-5 less than true odds |
| Standard offshore | 5-8% | $5-8 less than true odds |
| TAB NZ | 10-15% | $10-15 less than true odds |
This is exactly why we keep banging on about comparing odds across multiple bookies. The difference between a 3% and 12% margin over hundreds of bets is serious money. Rooster.bet and 22bet consistently had the tightest margins on NZ sports in our testing.
Here's the concept that separates punters who win long-term from everyone else. A value bet is when the true probability of an outcome is higher than what the odds suggest. Put simply: the odds are better than they should be. Finding and backing these situations consistently is how the small percentage of profitable bettors actually make money.
Crusaders vs Blues. Your analysis says the Crusaders have a 55% chance. The bookie's got them at 2.00 (implied probability 50%). Let's run the numbers:
Value = (0.55 x 2.00) - 1 = 1.10 - 1 = +0.10
Positive result (+0.10 or 10%). That's a value bet. Over time, backing these consistently will return a profit. Now if they were only offering 1.70 (implied 58.8%), the calculation gives: (0.55 x 1.70) - 1 = -0.065. Negative. No value. Pass on it.
"You don't need to win every bet. You need to consistently find situations where the odds are better than the true probability. That's value betting, and it's the only path to long-term profit that actually works."
This is the easiest way to improve your results without changing anything about how you analyse games. Just check a few different bookies before placing each bet. Different platforms set different odds on the same event, and always taking the best price compounds into seriously better returns. It's called "line shopping" and every sharp bettor does it.
Quick example: if you place $100 bets on 200 rugby matches per year and consistently grab odds 0.05 better than average by shopping around, that's roughly $1,000 extra in your pocket over the year. Same predictions, better returns.
| Sportsbook | All Blacks | Draw | South Africa | Margin |
|---|---|---|---|---|
| Rooster.bet | 1.78 | 21.00 | 2.15 | 3.8% |
| 22bet | 1.75 | 23.00 | 2.20 | 3.5% |
| Ivibet | 1.74 | 21.00 | 2.18 | 4.2% |
| Goldenbet | 1.72 | 20.00 | 2.15 | 5.1% |
| TAB NZ | 1.65 | 18.00 | 2.05 | 11.2% |
Look at the difference. Backing the All Blacks? Rooster.bet gives you 1.78 vs TAB NZ's 1.65. That's $13 more in your pocket on a $100 winning bet. Same prediction, different bookie. For the Springboks, 22bet at 2.20 beats TAB NZ's 2.05 by $15 per hundred. It adds up fast.
Keep active accounts at 3-5 different bookies so you've always got access to the best price. From our testing, Rooster.bet and 22bet consistently offer the sharpest odds on NZ rugby and cricket.
Theory is great, but let's make it concrete with actual NZ sports scenarios. Rugby and cricket - the two sports that matter most to Kiwi punters.
Match Winner: All Blacks 1.55 | Draw 26.00 | England 2.60
Handicap (-10.5 NZ): All Blacks 1.90 | England 1.90
Total Points (O/U 45.5): Over 1.85 | Under 1.95
First Tryscorer: Mark Tele'a 8.00 | Caleb Clarke 9.00 | Sevu Reece 10.00
A $50 bet on the All Blacks at 1.55 returns $77.50 ($27.50 profit). A $20 bet on Caleb Clarke as first tryscorer at 9.00 returns $180 ($160 profit). A $30 multi combining All Blacks + Over 45.5 at combined odds of 2.87 returns $86.03.
Match Winner: Black Caps 2.30 | Australia 1.65
Top NZ Batsman: Kane Williamson 4.50 | Devon Conway 5.00 | Tom Latham 7.50
Total NZ Runs (O/U 265.5): Over 1.85 | Under 1.90
Man of the Match: Williamson 6.00 | Cummins 8.00 | Boult 12.00
A $50 bet on the Black Caps at 2.30 returns $115 ($65 profit). A $10 bet on Williamson as top NZ batsman at 4.50 returns $45 ($35 profit). Combining Black Caps to win + Over 265.5 runs gives combined odds of 4.26 - a $25 bet returns $106.38.
Odds aren't set in stone. They shift based on betting volume, team news, and market conditions. If a key All Black gets ruled out, their odds lengthen (go up) and the opposition's shorten (come down). Getting your bets in early, before the market adjusts to new info, is often where the best value sits.
Want to go deeper on rugby markets and strategies? Check our rugby betting guide. For welcome bonuses that let you test different bookies, see our bonuses guide.
