The most common question new sports bettors ask is: “How much money can I win?”
The question professional bettors ask is: “How much money do I need to survive?”
In sports betting, having a winning strategy is only half the battle. The other half is having a bankroll deep enough to withstand the inevitable losing streaks (variance). Our Bankroll Requirement Calculator uses the “Reverse Risk of Ruin” formula to tell you exactly how much capital you need to start with to ensure your chance of going broke is virtually zero.
Bankroll Requirement
How to Use the Bankroll Calculator
This tool works backwards from your safety goals. Instead of telling you your risk based on your current cash, it tells you the cash required to meet your safety standards.
- Enter Win Probability (%): What is your historical strike rate? (e.g., 55% for a solid spread bettor).
- Note: Be realistic. If you overestimate this, the calculator will suggest a bankroll that is too small, putting you at risk.
- Enter Average Odds: What price do you usually bet?
- You can toggle between Decimal (e.g., 1.91) and American (e.g., -110) formats.
- Set Unit Size ($): How much do you want to bet per game? (e.g., $50).
- Adjust Risk of Ruin: Use the slider to determine your safety level.
- 1% or lower: Recommended for professionals who rely on betting for income.
- 5% – 10%: Acceptable for recreational bettors who can reload their account if they bust.
Related Tools: Once you have established your bankroll, use the Kelly Criterion Calculator to optimize your bet sizing. If you are unsure what your true win probability is, use our Odds Converter & Implied Probability Tool to analyze the bookmaker’s lines.
Real-World Examples: Variance & Bankroll Size
Why isn’t there a “one size fits all” bankroll? Because betting on longshots requires much deeper pockets than betting on favorites.
Example 1: The “Safe” Spread Bettor
You bet on NFL spreads at standard -110 (1.91) odds. You are a sharp bettor with a 55% win rate.
- Edge (ROI): ~5%.
- Variance: Low.
- Required Bankroll (1% Risk): The calculator might suggest around 25 to 30 Units. Since you win often, you don’t need a massive cushion.
Example 2: The “Underdog” Hunter
You bet on UFC underdogs at average odds of +200 (3.00). You have a 35% win rate.
- Edge (ROI): ~5% (Same profitability as the spread bettor!).
- Variance: High. You will lose more often, but win big when you do.
- Required Bankroll (1% Risk): The calculator will suggest 60 to 80 Units. Even though you are just as profitable as the NFL bettor, you need double the money to survive the longer losing streaks inherent in underdog betting.
Frequently Asked Questions (FAQ)
What is Risk of Ruin (RoR)?
Risk of Ruin is the mathematical probability that you will lose your entire bankroll before you double it. A professional bettor typically aims for a Risk of Ruin below 1%.
Why does the calculator say “Infinite” bankroll?
If your expected value (EV) is negative (e.g., a 50% win rate on -110 odds), no amount of money can save you. You are mathematically guaranteed to lose in the long run. You must have a winning edge (positive ROI) for bankroll management to matter.
What is a “Unit”?
A unit is a standard measure of your bet size, usually 1% to 2% of your total bankroll. Using units allows bettors to compare performance regardless of how much money they actually have.
Does this calculator assume Flat Betting?
Yes. This calculation is based on the assumption that your bet size (in dollars) remains constant. If you use proportional betting (like Kelly Criterion), your risk of ruin theoretically drops to zero (since you bet less as you lose), but your bankroll can still shrink to unusable levels.