How to Calculate Odds in Your Head Like a Pro

How to Calculate Odds in Your Head Like a Pro

Unless you are in a casino to lose money, mastering the art of odds calculation quickly and correctly is critical. This gaming strategy helps you make informed decisions. Consequently, your investments last longer so that you can sit at the table long enough to make a profit.

What Are Betting Odds?

At first sight, betting odds may appear confusing and complicated. Odds help you know what is likely to happen and what your potential earnings look like. Therefore, calculating odds means that you’re attempting to accurately envision what is expected to happen and what is not. It follows that when you predict correctly, you win money.

Calculating bets starts with understanding that for any given event, there are a certain number of possible outcomes. A game is as likely to go against your bet as it is to work in your favor. When analyzed well, betting odds are the key to dominating in any betting game whether online or offline.

Casinos present odds in three forms: fractions, percentages, or decimals.

Calculate Fraction Odds Like a Pro

Calculate Fraction Odds Like a ProFraction odds appear as numbers separated by a slash. Examples are 10/1, 9/2, or 6/2. Most popular betting sites prefer this method of odd calculation because it is easy to identify and understand. Still, the inability to correctly calculate odds fast has caused people to lose significant amounts of money.

When faced with the following odds, fast calculations will provide you with the crucial information required to make a winning prediction:
8/1 odds follows 1/ (8+1) = 0.11 (An 11% chance that your prediction is correct.)
4/1 odds follows 1/ (4+1) = 0.20 (A 20% chance that your prediction is correct.)
1/2 odds follows 2/ (2+1) = 0.67 (A 67% chance that your prediction is correct.)

The fraction method is easy to calculate in your head even as the dice roll on the table. You can estimate your winnings in the spur of the moment. That way, you invest the right amount to generate a decent profit. Use the same method to make fast calculations of your possible earnings over and above your stake.

8/1 means that every $1 investment can earn you $8 in profit.
4/1 means that every $1 investment can earn you $4 in profit.
1/2 means that every $1 investment can earn you $1 in profit.

Calculate Decimal Odds Like a Pro

Calculating decimal odds can be done fast and accurately. They are developed from the fractions method. Simply calculate by multiplying the odds with the amount at stake, less the investment as shown below.

Winnings = (Odds × Amount at stake) – Amount at stake
3.1 – (3.1 × $20) – $20 = $62 – $20 = $42 profit
4.0 – (4.0 × $20) – $20 = $80 – $20 = $60 profit
1.5 – (1.5 – $20) – $20 = $30 – $20 = $10 profit

Calculate percentage Odds Like a Pro

Calculate percentage Odds Like a ProAlthough rare, some betting companies may present odds in percentage form. Any percentage you’ll come across indicates the measure of success per 100 attempts. A 25% odd simply means that you are likely to succeed 25 times if you play 100 times.

Simplify the percentage odds into a ratio by dividing the percentage with 100. This gives you a clear picture of what to expect if you only play once. Divide the decimal with 1 to get the ratio. With the ratio odd, you can comfortably calculate the possible winnings for every try.
Calculate 20% as 20 ÷ 100 = 0.20
Calculate 40% as 40 ÷ 100 = 0.40

To convert the percentage expressed as a decimal into a ratio. Divide 1 with the percentage. Then subtract one from the resulting value to find the first number of the odd ratio as in the example below. Lastly, write the figure in the X/1 format.

Calculate 0.20 as 1 ÷ 0.20 = 5, 5 – 1 = 4 giving you a 4/1 odds ratio
Calculate 0.08 as 1 ÷ 0.08 = 12.5, 12.5 – 1 = 11.5 giving you an 11.5/1 odds ratio

Eventually the 20 and 8 percent odds translate to 4/1 and 11.5/1 respectively, showing that your $1 stake will earn you $4 and $11.50.
Applying Odds Calculations in the Casino

Mastering the formulas and calculating odds in your head like a pro requires you to practice the tactics frequently. The American roulette table has 38 different pockets running through 0 to 36. The table also includes zero (0), and double zero (00). When you play twice, the odds are 38/2 or 18/1. Increase the number of wagers to increase your chances of winning.

Let’s say you want to produce a line of diamonds in a 3-reel slot machine with 20 different images. Chances that you will produce the exact prediction are 20 × 20 × 20 = 8,000, 1 in 8,000. A 5-reel slot machine’s predictions are 20 × 20 × 20 × 20 × 20 = 3,200,000, 1 in 3.200,000. The 5-reel slot machine reduces your chances of winning even further. The depressing figures are the main reason why casinos present slot machine odds in percentage form.

Calculating House Edge

Casinos rely on house edge to keep their doors open. This advantage over players to enables them to turn a profit. It is perfectly legal. The house edge allows the casino to meet its payroll obligations, pay utility bills, and maintain gaming equipment.

The American Roulette, for instance, has a 5.26% house edge (see calculations below). This advantage is incorporated into the game using mathematical formulas under the keen eye of licensing bodies.

The chances that you will win the American Roulette are 18/38 because 18 red and 18 black pockets exist out of the total 38. However, your chances of losing increase to 20/38.

Calculate the expected value as:
1 (18/38) + -1 (20/38)
18/38 – 20/38
-2/38 = -1/19

Beating House Edge

The law allows the casino to retain a fixed percentage of player earnings as house edge. However, it is highly unlikely that the establishment will win more than it loses. Most casinos end up setting an advantage below standard thresholds to increase player earnings and keep them engaged for longer.

When you calculate odds in your head like a pro, you give the casinos a good run for their money. You and the casino are practically on the same level. You have gone the extra mile to increase your winnings and protect your money. And the casino must pay the bills and maintain the equipment.

Sometimes casinos offer promotional opportunities. Players can earn more money than they wager, up to 100% in some instances. Such promotions create buzz about the casino and get more people interested. For smart players, these are opportune moments to turn in a generous profit.

Increase Odds Using Accumulator Bets

lacing several bets on the same game, accubets, or multibets increase your odds significantly. Even though the risk increases with every added leg, the odds are higher and so are the potential winnings.

Use accubets for games with two opponents, to begin with. Because the game can only result in a win, draw, or loss, your chances of winning increase significantly.


Every casino game presents a different set of odds. Even so, understanding how to calculate odds in your head like a pro is very beneficial. It enables you to stay atop any casino game or betting environment of your choice. Simply read the odds. Know how likely it is that your prediction is correct and how much you stand to win.

Disclaimer: All images are copyright to their respective owners and are used by Top Casino Picks for informational purposes only.

Relevant news

$25 Free Chip
No luck today!
25 Free Spins
Try again!
$4000 Bonus
$50 Amazon Card
Get a chance to win amazing prizes !
Spin the wheel and get a chance to receive amazing gifts or bonuses!
Our in-house rules:
  • One game per user
  • Cheaters will be disqualified.