Gambling Unit Calculator

In professional betting, performance is measured in units, not dollars. A “unit” is a standardized bet size — typically a fixed percentage of your total bankroll. This lets bettors with different bankroll sizes compare results on equal terms: winning 5 units means the same thing whether your unit is $10 or $500.

Our Unit & Stake Calculator works in two directions: enter your bankroll to find your unit size, or enter your desired unit to find the bankroll needed. It also includes an optional Kelly Criterion module for edge-based sizing, a drawdown risk assessment, and a staking cheat sheet for quick reference.

How to Use the Unit Calculator

Mode 1: Bankroll → Unit (Standard)

Use this if you have a set bankroll and want to know how much to bet per game.

1. Enter Total Bankroll: Your total gambling funds (e.g., $1,000).
2. Select Unit Size %: The percentage of your bankroll that equals one unit. Common choices: 1% (standard/conservative), 2% (moderate), 3% (aggressive). You can also enter a custom percentage.
3. (Optional) Drawdown Limit: Enter a stop-loss amount — the maximum you are willing to lose. The calculator uses this for the risk assessment.
4. (Optional) Kelly Criterion: Enable this toggle if you know your edge and average odds. The calculator shows Full, Half, and Quarter Kelly stake sizes alongside your flat unit.
5. Results: Your unit size in dollars, a staking cheat sheet (0.5u through 5u), Kelly comparison (if enabled), and a risk assessment based on consecutive-loss runway.

Mode 2: Unit → Bankroll (Reverse)

Use this if you know how much you want to bet per game (e.g., $25) and want to know what bankroll supports that bet size responsibly.

1. Switch to “Unit → Bankroll” mode.
2. Enter Desired Unit Size: Your target bet in dollars (e.g., $25).
3. Select Unit Size %: Same percentage scale — at 1%, a $25 unit requires a $2,500 bankroll.
4. Result: The required bankroll to maintain that bet size at the chosen risk level.

Flat Betting vs. Kelly Criterion

Flat Betting (Fixed Unit)

Flat betting means wagering the same dollar amount on every bet, regardless of confidence or perceived edge. It is the simplest and safest approach: you choose a percentage (e.g., 1%), calculate the unit, and bet that amount every time.

Strengths: eliminates emotional over-betting, easy to track, limits drawdown. Weaknesses: does not adjust for stronger or weaker edges.

Kelly Criterion (Edge-Based)

The Kelly Criterion determines the mathematically optimal bet size to maximize long-run bankroll growth, given your edge and the odds:

Kelly % = Edge / (Decimal Odds − 1)

Where Edge = (True Probability × Decimal Odds − 1). For example: if you estimate a 55% true probability on a 2.00 line, your edge = (0.55 × 2.00 − 1) = 0.10, or 10%. Kelly % = 0.10 / (2.00 − 1) = 10%.

In practice, Full Kelly is too volatile for most bettors — a bad estimate of your edge leads to massive over-betting. Professionals typically use:

• Half Kelly: Bet half the Full Kelly amount. Captures ~75% of the growth rate with much lower variance.
• Quarter Kelly: Even more conservative. Common among bankroll-sensitive bettors.

The calculator shows all three levels when Kelly is enabled.

Important: Kelly assumes you know your true edge. If your edge estimate is wrong, Kelly sizing amplifies the error. Flat betting is safer when you are uncertain about your edge.

Understanding the Risk Assessment

The calculator estimates a consecutive-loss runway: how many losing bets in a row you can absorb before reaching your drawdown limit (or going bust). This is a simplified worst-case metric — real drawdowns alternate wins and losses. But it gives a useful floor:

• Below 10 bets: High risk. Even a moderate cold streak can wipe out your limit. Consider smaller units.
• 10–30 bets: Moderate. Standard variance can push you into uncomfortable territory.
• Above 30 bets: Safe buffer. Your bankroll can absorb normal variance at this unit size.

Examples

Example 1: Conservative Approach

• Bankroll: $2,000. Unit size: 1%.
• 1 Unit = $20. Cheat sheet: 0.5u = $10, 2u = $40, 3u (max) = $60.
• Risk: A 10-game losing streak costs $200, or 10% of the bankroll. Survivable.

Example 2: Aggressive with Kelly

• Bankroll: $1,000. Estimated edge: 8% on average 1.90 odds.
• Full Kelly: 8% / 0.90 = 8.9%. Full Kelly stake = $89.
• Half Kelly (recommended): $44.50 per bet (4.45% of bankroll).
• Risk: At Half Kelly, a 10-bet losing streak costs $445 — nearly half the bankroll. This is why Kelly requires genuine, verified edge.

Frequently Asked Questions (FAQ)