You’ve found an edge. You’ve stripped the vig, estimated the true probability, and the numbers say this bet has positive expected value. Now the question that most punters get wrong: how much do you bet?
Staking is where the maths of bankroll management meets the reality of variance. The wrong staking method can turn a profitable edge into a losing strategy. The right one maximises your growth while keeping you in the game. This guide compares the four main approaches and helps you pick the one that fits your situation.
Flat Staking
The simplest method. Every bet is the same size, regardless of odds, confidence, or perceived edge.
How it works: You set a unit — say 2% of your bankroll, or $40 on a $2,000 bankroll. Every bet is $40 whether you’re backing a $1.50 favourite or a $4.00 outsider.
Pros: Simple. Impossible to mess up. Removes emotion from staking decisions. Easy to track and analyse. Forces discipline during losing streaks because the impulse to increase stakes is eliminated by the rule.
Cons: Doesn’t adjust for edge size. A bet where you estimate 8% edge gets the same stake as one with 2% edge. Over time, this leaves money on the table because you’re underweighting your strongest opportunities and overweighting your weakest.
Best for: Beginners, punters who don’t yet have a reliable edge measurement, and anyone who struggles with staking discipline. If you’re not sure which method to use, start here.
Expected growth: Moderate. Flat staking produces consistent, linear bankroll growth (or decline) with lower variance than Kelly-based methods.
Kelly Criterion
The mathematically optimal staking method. Kelly calculates the exact percentage of your bankroll to bet based on your estimated edge and the odds available.
How it works: Kelly % = (bp – q) / b, where b is the net decimal odds (odds minus 1), p is your estimated win probability, and q is the loss probability (1 – p). Use the Kelly Calculator to compute this instantly.
Example: You estimate a team has a 55% chance of winning. Odds are $2.10. Kelly % = (1.10 × 0.55 – 0.45) / 1.10 = 14.5%. On a $2,000 bankroll, that’s $290.
Pros: Mathematically optimal for long-term growth. Bets more when your edge is larger, less when it’s smaller. Over infinite bets, Full Kelly maximises the growth rate of your bankroll.
Cons: Full Kelly produces enormous variance. The example above — betting 14.5% of your bankroll on a single bet — would terrify most punters, and for good reason. Full Kelly assumes your probability estimates are perfectly accurate, which they never are. Overestimating your edge by even a few percentage points can lead to aggressive overbetting.
The critical problem: Kelly requires accurate probability estimates. If you think a team has a 55% chance but the true probability is 50%, Full Kelly will systematically overbet and destroy your bankroll. Since no one’s estimates are perfect, Full Kelly is almost never used in practice.
Fractional Kelly
The solution to Full Kelly’s volatility. Instead of betting the full Kelly stake, you bet a fraction — typically Half Kelly (50%) or Quarter Kelly (25%).
How it works: Calculate Full Kelly, then multiply by your fraction. Using the example above: Full Kelly = 14.5%, Half Kelly = 7.25%, Quarter Kelly = 3.6%.
Half Kelly delivers roughly 75% of Full Kelly’s long-term growth rate but with substantially reduced variance. This is the most popular choice among professional bettors because it balances growth with survivability.
Quarter Kelly delivers roughly 50% of Full Kelly’s growth rate with very low variance. Best for punters who aren’t fully confident in their probability estimates or who are betting in higher-variance markets.
Pros: Still adjusts stake to edge size, but with a margin of safety against estimation errors. A significant overestimate of your edge that would blow up a Full Kelly bettor only produces moderate losses for a Half Kelly bettor.
Cons: Slower growth than Full Kelly if your estimates are accurate. Requires the same probability estimation work as Full Kelly.
Best for: Experienced punters with a documented edge, comfortable with probability estimation, and disciplined enough to follow the formula even when it recommends smaller stakes than their gut suggests.
Percentage Staking
A middle ground between flat staking and Kelly. Your stake is a fixed percentage of your current bankroll, so it automatically adjusts as your bankroll grows or shrinks — but it doesn’t vary based on edge size.
How it works: You bet 2% of your current bankroll on every bet. If your bankroll is $2,000, you bet $40. If it grows to $2,500, you bet $50. If it drops to $1,600, you bet $32.
Pros: Automatically scales — you bet more when winning (compounding) and less when losing (protecting). Simple to implement. No probability estimation required.
Cons: Like flat staking, it doesn’t adjust for edge size. A high-confidence bet gets the same percentage as a marginal one. Also, because stake size drops as the bankroll shrinks, recovering from a drawdown takes longer than with flat staking.
Best for: Punters who want automatic compounding without the complexity of Kelly estimation.
Comparison Table
| Method | Simplicity | Growth | Variance | Edge Estimate Needed? |
|---|---|---|---|---|
| Flat Staking | High | Moderate | Low | No |
| Full Kelly | Low | Maximum | Very High | Yes (must be accurate) |
| Half Kelly | Medium | High | Medium | Yes |
| Percentage | High | Moderate | Low-Medium | No |
Which Method Should You Use?
If you’re new to serious betting: Start with flat staking at 1-2% of bankroll. Focus on developing your analysis and proving your edge before optimising your staking.
If you have 500+ tracked bets with positive CLV: Move to Half Kelly. Your probability estimates are proven enough to trust, and the Kelly adjustment will improve your growth rate.
If you bet multiple sports and markets: Use percentage staking as your base, with Kelly adjustments for your highest-confidence bets. This gives you automatic bankroll scaling with the option to overweight your strongest plays.
If you bet high-variance markets (tryscorer, futures): Use Quarter Kelly or flat staking with reduced units (0.5-1%). The variance in these markets makes Full or even Half Kelly too aggressive.
The most important thing is consistency. Any staking method applied consistently will outperform an ad-hoc approach where stake sizes are determined by emotion, gut feel, or the desire to chase losses.
Related Reading
- Bankroll Management — The framework for survival
- Closing Line Value (CLV) — Prove your edge before optimising stakes
- Expected Value (EV) — The foundation of profitable betting
- Market Percentages (The Vig) — What you’re paying to play
- Cognitive Biases — Why punters overbet and chase
- The Professional Workflow — Staking as step 4
Tools
Kelly Calculator Calculate Full, Half, and Quarter Kelly stakes Vig Remover Find true probability before applying Kelly Betting Tracker Track stakes and ROI by staking method Multi Calculator See combined probability before staking