BETTING / GROWTH PROJECTIONS
Bankroll Growth Calculator and Monte Carlo Simulator(2026)
Plot 100 simulated bankroll trajectories, estimate time-to-target, and see how compounding compares to flat staking over your full horizon.
Demo scenarios
Three realistic compounding profiles you can tune from
1-2% safe, 3-5% aggressive
Break-even win rate: 51.3%
Edge per bet: +7.25%
Goal: $2000.00
Enter parameters to run the simulation
Six steps from inputs to plan
The same workflow we use to plan our own bankroll-growth strategies.
Determine your starting bankroll
Use only money you can afford to lose entirely. Separate it from rent, savings, or living expenses.
Estimate your edge realistically
If you don't track Closing-Line Value or have 1,000+ bets of history, assume your edge is 0 until proven.
Choose a sizing method
Flat 1-2% works for most. Fractional Kelly (1/4 or 1/2) for advantage players with verified edge.
Set your time horizon and target
Pick a realistic horizon (1, 3, 5, or 10 years) and a multiplier target (2x, 5x, 10x).
Review the projected trajectory
Look at the median path, the 5th-95th band, and the worst-case drawdown. Be ready for the bottom of the cone.
Save your plan and re-evaluate
Export the plan, re-check edge and CLV every 500-1,000 bets, adjust if conditions shift.
What Is a Bankroll Growth Calculator and Why Do You Need One
In short, a bankroll growth calculator shows you how your bankroll could grow over hundreds or thousands of bets given your win rate, odds, and unit size. Not one polished number from a sales pitch, but the full range of outcomes, from the brutal runs to the good ones. Below we cover what this tool is, how it helps in practice, and how to use it on toolsgambling.com.
What This Tool Actually Does
The bankroll growth calculator is a Monte Carlo simulator. You feed it your inputs, starting bankroll, average odds, win rate, stake percentage, and time horizon, and it runs 100 random simulations of your betting journey. Each simulation is its own story: some hit a brutal downswing, others catch a hot streak. What you get back is not just an average, but a median, upper and lower percentiles, and the probability of hitting your target.
Unlike a simple compound interest calculator that multiplies your bankroll by a fixed return, this tool honestly accounts for variance. That is why the chart is not one smooth line going up, it is a band: a wide spread of outcomes that narrows toward the median. This is what real bankroll growth looks like when you have an edge but no guarantees over a short sample.
When I plugged in my actual betting log of around 3000 bets at roughly a 54% win rate on odds of 1.9, the median path reached a 2x bankroll, but the bottom of the band dipped as far as minus 35% several times. That picture was what finally stopped me from bumping my unit size after every good month.
Why You Need a Bankroll Growth Calculator
The biggest benefit is that it cures two extremes: blind optimism and panic during a drawdown. You can see upfront which drawdowns are perfectly normal at your stake percentage, so you stop abandoning a solid strategy the moment results turn negative. You also get a clear sense of what edge you actually need for a goal like doubling your bankroll to be realistic rather than wishful thinking.
See Real Risk, Not Marketing Numbers
The calculator shows you risk of ruin and the worst drawdown at the 95th percentile. You can see that with a 5% unit, even with a positive edge, a drawdown of 40-50% from peak is a routine event, not a signal to quit.
Find the Unit Size That Suits Your Mindset
Adjust your stake percentage and instantly see how the median outcome and bankruptcy probability shift. It beats generic advice because you find the right balance between growth speed and peace of mind for your specific bankroll.
Compare Compounding Against Flat Staking
The tool models both side by side. Compounding scales your unit with the bankroll and wins over a long horizon, but it comes with deeper drawdowns. Flat staking grows more slowly but is much harder to wipe out.
How to Use the Calculator on toolsgambling.com
The tool runs entirely in your browser on toolsgambling.com, no sign-up or payment required. The simulation updates instantly as you change any field. Here is the recommended workflow.
- 01
Enter Your Starting Bankroll and Currency
Only enter money you could afford to lose entirely. Your bankroll should be kept separate from rent, savings, and everyday expenses. Select your currency from the dropdown to the left of the field.
- 02
Set Your Win Rate and Average Odds
Use figures from your real betting history, not what you are hoping for. Below the odds field the tool immediately shows you the break-even win rate. If yours is lower, your edge is negative and your bankroll will not grow.
- 03
Choose Your Unit Size and Time Horizon
Set your stake percentage (1-2% is conservative, 3-5% is aggressive) and pick a horizon from 1 to 10 years. Then set a target: 2x, 5x, or 10x. The calculator will show how many bets the median path needs to get there.
- 04
Read the Chart and Save Your Plan
Focus on the shaded band and the median line. The bottom of the band is your realistic worst-case scenario, and it is worth being prepared for it. Click Snapshot to save your calculation, or Export Plan to copy it as text.
Bankroll Growth Glossary
To read your projection without confusion, keep these core concepts handy. Each one directly affects the shape of the chart and the final numbers.
Core Concepts
- Your mathematical advantage per bet, expressed as a percentage of the stake. A positive edge means profit over time. A negative edge means a slow but inevitable wipeout.
- The natural spread of results. Even with a positive edge you will hit losing runs. A drawdown is the drop in your bankroll from a local peak, and it does not mean your strategy is broken.
- Reinvesting your profits so the unit grows with the bankroll. It accelerates growth exponentially but also magnifies drawdowns in absolute terms.
- The probability of losing your entire bankroll. It depends more than anything on unit size. A lower stake percentage sharply reduces the chance of a complete wipeout.
Edge
Variance and Drawdown
Compounding
Risk of Ruin
Worth Keeping in Mind
The calculator is a model, not a prediction. It shows the range of likely outcomes based on your inputs, but your real results will always land somewhere inside that band. Check your edge against CLV every 500-1000 bets and do not scale up your unit if that edge has disappeared.
Free Tools on toolsgambling.com
On toolsgambling.com you can use the Red Door Roulette Calculator, the Kelly calculator, the risk of ruin calculator, and dozens of other tools for free, with no sign-up needed. They work best together: plan your bankroll growth here, calculate your optimal unit size with Kelly, and check your risk of ruin separately.
Gamble Responsibly
Betting is entertainment, not a source of income. Any bankroll growth projection only holds if you genuinely have a positive edge, and most bettors do not. Only stake what you can afford to lose, never chase losses, and never borrow money to bet. 18+. If gambling stops being fun, get free support at BeGambleAware.org.
What this calculator actually computes
The math behind the chart, with no marketing fluff. If something here doesn't make sense, the calc isn't wrong — the assumption you brought to it probably is.
What this calculator computes
Each Monte Carlo path is a random walk with edge: at every step, win probability p moves your bankroll by stake × (odds-1), and (1-p) moves it by -stake. Compound mode rescales stake = bankroll × unit%. Flat mode keeps stake = starting × unit%. Run 100 paths, take percentiles. That's it.
Why growth strategies fail
Three failure modes dominate: edge erosion (lines move against you, sharps copy your angle), over-staking (5%+ units feel fine until you hit the 95th-percentile drawdown), and emotional sizing (chasing losses, doubling on tilt). Variance you can survive. The other three you can't.
When compounding makes sense
Compounding wins when (a) your edge is real and stable, (b) your psychology can handle 30-50% drawdowns from peak, and (c) you have time horizons measured in years not weeks. If any of those is shaky, flat staking is safer — slower but harder to ruin.
Pair this with the rest of the toolkit
Each tool answers a different bankroll question. Use them together for a complete plan.
Bankroll Calculator (universal)
Universal sizing for sports, blackjack, poker, and video poker. Risk of ruin, units, Kelly modes.
Kelly Criterion Calculator
Compute the mathematically optimal stake for any edge + odds combination.
Risk of Ruin Calculator
Model the probability of going broke given your bankroll, unit size, and edge.
Staking Plan Calculator
Compare flat, percentage, Kelly, and unit-based staking plans on identical inputs.
Bankroll growth — frequently asked questions
Related guides
Articles that pair with this calculator's projections.
Bankroll Growth vs Flat Staking
Side-by-side comparison: when each approach wins, with concrete bankroll trajectories.
What is Bankroll Management?
The core concept: why a bankroll exists, how it differs from gambling money, and the rules that protect it.
How to Calculate Bankroll Units
Convert your bankroll to bet units the right way — flat, percentage, and Kelly-based methods.
Bankroll Management for Sports Betting
Sport-specific bankroll rules: parlays, live betting, and game-by-game volatility.
Bankroll Calculator vs Kelly
When to use straight bankroll sizing and when Kelly's optimal-growth math is the right tool.