What is EV in Sports Betting? Expected Value Guide

Expected Value (EV)

Expected Value is what you'd win on average if you made the same bet over and over again many times. It tells you whether a bet is worth making in the long run.

Simple Example #1: Coin Flip Game

Imagine you play a coin flip game where you pay $1 to play. If the coin lands on heads, you win $2. If it lands on tails, you get nothing.

• Heads happens 50% of the time: You win $2, but you paid $1, so you profit $1
• Tails happens 50% of the time: You lose your $1

Your Expected Value = (50% × $1 profit) + (50% × -$1 loss) = $0.50 - $0.50 = $0

This means if you played this game 100 times, you'd break even on average. It's a fair game.

Simple Example #2: Dice Roll

Let's say you roll a normal six-sided die. Each number (1, 2, 3, 4, 5, 6) has an equal chance of appearing.

The Expected Value = (1 + 2 + 3 + 4 + 5 + 6) ÷ 6 = 3.5

So if you rolled the die many, many times and calculated the average, you'd get close to 3.5.

Now Apply It to Betting

Same logic! Let's say you bet $100 on a player prop at +150 odds, and you think it hits 45% of the time:

• Win (45%): Win $150 → 0.45 × $150 = $67.50
• Lose (55%): Lose $100 → 0.55 × -$100 = -$55
• EV = $67.50 - $55 = +$12.50 per $100 bet

This is a +EV bet because your expected value is positive. Over many bets like this, you profit.

The Key Insight

It doesn't matter if this specific bet wins or loses.

If you make +EV bets consistently:

• Some win, some lose
• But math wins over time

+EV vs -EV

DMP Note

Every prop in DMP shows an EV calculation. We find the gap between what the market says and what we calculate. Bet only when the math is in your favor.

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This is the mindset shift. Stop asking "Will this win?" Start asking "Is this +EV?"

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Calculate EV

Use the EV Calculator → — Enter your probability and odds to calculate expected value

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Win Rate vs ROI

One of the most misunderstood concepts in betting is the relationship between win rate and return on investment. Bettors often focus on win rate as a measure of success, but a 55% win rate and a 60% win rate produce dramatically different long-term outcomes at standard juice.

Win Rate vs ROI at Standard -110 Juice:

The difference between 53% and 55% — just 2 percentage points — is the difference between $355 and $1,391 annually. Small edges compound into significant profits over volume. This is why EV matters more than gut feel: a consistent 2% probability advantage creates life-changing returns over thousands of bets.

ROI formula:

ROI = ((Win% x Payout) - (Loss% x Stake)) / Stake x 100

At -110 odds:

ROI = ((Win% x 0.909) - (1 - Win%)) x 100

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Break-Even Reference Table

Before betting any line, you should know the minimum win rate required just to break even at those odds. This table converts common American odds to the implied probability needed for a break-even outcome (zero profit, zero loss over time).

Break-Even Win Rate by Odds:

| American Odds | Implied Probability | Break-Even Win Rate | |--------------|--------------------|--------------------|| | -150 | 60.0% | 60.0% | | -140 | 58.3% | 58.3% | | -130 | 56.5% | 56.5% | | -125 | 55.6% | 55.6% | | -120 | 54.5% | 54.5% | | -115 | 53.5% | 53.5% | | -110 | 52.4% | 52.4% | | -105 | 51.2% | 51.2% | | +100 | 50.0% | 50.0% | | +105 | 48.8% | 48.8% | | +110 | 47.6% | 47.6% | | +115 | 46.5% | 46.5% | | +120 | 45.5% | 45.5% | | +130 | 43.5% | 43.5% | | +140 | 41.7% | 41.7% | | +150 | 40.0% | 40.0% | | +200 | 33.3% | 33.3% | | +300 | 25.0% | 25.0% |

At -110, you need to win 52.4% of the time just to break even. That means the first 2.4% of your "edge" goes to the house. Only the edge above 52.4% generates profit. This is why vig matters so much — and why betting at -115 instead of -110 (moving your break-even to 53.5%) costs you significantly more than it appears.

Formulas:

For negative odds:

Break-even % = |Odds| / (|Odds| + 100) x 100

For positive odds:

Break-even % = 100 / (Odds + 100) x 100