Trading Account Growth CalculatorCompounding Over Time & Kelly Criterion

The two questions this calculator answers

Account growth comes down to two questions a single number can't answer: how big can this realistically get, and how long will it take to get there? Both are compounding questions, and compounding is where intuition fails — small differences in edge or risk produce enormous differences in where you land a year out, and the path there is never the straight line a spreadsheet draws.

Three inputs drive everything: your edge (expectancy in R per trade), how often you trade, and how much you risk each time. Multiply them and you get a monthly growth rate; compound that rate and you get a trajectory. The simulation above runs that trajectory thousands of times so you see the realistic spread of where your account ends up — not a single optimistic line.

How long until you hit your number

Start with the monthly engine. If your edge holds, your account grows each month by roughly:

monthly growth ≈ expectancy (R) × trades per day × sessions × risk per R

Hold the edge at a realistic, post-cost 0.3R across three trades a day and 20 sessions — 18R of expected profit a month — and the only dial left is risk per trade. Here is how long the median path takes to double and quadruple the account at each setting:

The table is seductive and dangerous in equal measure. Doubling risk roughly halves the time — but those numbers are the median path, and the median is the one outcome you are least likely to live exactly. Variance makes the fast rows far riskier than they look, which is the entire reason to simulate rather than read a single line off a table.

Why the simulation beats the table

No equity curve experiences the average. Yours will be one specific path through the variance, and paths diverge enormously: the same 0.3R edge at 1% risk produces some 12-month paths that double and others that spend half the year underwater, from identical inputs. The order of the trades — which the table can't capture — decides which one you get.

That's what the Monte Carlo simulation above shows: thousands of possible futures for your exact numbers, as a fan of outcomes rather than a single line. The median path tells you what's typical. The lower percentiles tell you what you must be prepared to sit through — and that second number, not the headline growth rate, should drive your risk setting.

Risk per trade: the growth-vs-pain dial

Doubling risk per trade doubles expected growth and roughly doubles expected drawdown — but it does not double the pain, because drawdown pain compounds nonlinearly (a 30% hole needs 43% to climb out; see the drawdown calculator). For the same 0.3R-edge strategy:

The right reading of the table isn't "pick the row with the best return." It's: find the worst drawdown you could genuinely trade through without flinching, then take the largest risk whose simulated tail stays inside it. Traders who size beyond that don't usually blow up on math — they blow up on the behavior change that a too-deep drawdown triggers.

Kelly: the ceiling, not the setting

The Kelly Criterion answers a precise question: what fixed fraction of capital maximizes long-run compound growth for a given edge?

f* = W − (1 − W) ÷ R

For a 55% win rate with a 1.5 win/loss ratio: f* = 0.55 − 0.45 ÷ 1.5 = 25% of capital per trade. Nobody trades that, for two good reasons. Full Kelly routinely visits 50%+ drawdowns on the way to its optimal growth — mathematically survivable, humanly not. And Kelly assumes your edge estimate is exact; overestimate the edge even slightly and full Kelly oversizes you into negative territory. Betting half or a quarter of Kelly keeps most of the growth at a fraction of the violence, and conveniently lands in the same 0.5–2% region professionals use anyway. Treat Kelly as the ceiling that proves your 1% is sane, not as a target.

Realistic expectations, in actual numbers

Run the forecast honestly: a real, post-cost 0.25R edge, three trades a day, 0.5% risk, 20 sessions. That's 0.25 × 3 × 20 = 15R a month at 0.5% per R — roughly 7.8% monthly compounded, around 145% a year if everything holds. An exceptional outcome, built from modest-sounding inputs.

Notice what's absent: doubling monthly. Sustained 100%-per-month growth at survivable drawdowns implies an edge no measured intraday sample supports. When the simulation shows it, the input is wrong — usually an expectancy measured over 30 lucky trades. The same applies in reverse: if your honest inputs show 3–5% a month, that is not failure; compounded, it's a career.

And expect regime drift. An edge measured in trending volatility fades in chop; size that was comfortable at $25,000 feels different at $100,000. Re-measure expectancy quarterly and re-run the simulation when the inputs move — the forecast is only as current as the sample behind it (the expectancy calculator covers how large that sample must be).

Frequently asked questions

How long does it take to grow a trading account?

Edge × trades × risk sets your monthly growth rate. A realistic 0.3R edge, three trades a day, and 0.5% risk compounds at ~9% a month — about 8 months to double and 16 to quadruple on the median path. More risk shortens that but deepens the drawdowns you pass through.

How much should I risk per trade?

Most professionals: 0.25–2%, centered on 0.5–1%. Set it from the worst drawdown you can tolerate without changing behavior, not from the growth you want.

What is the Kelly Criterion?

f* = W − (1 − W) ÷ R — the risk fraction that maximizes long-run growth. It's a ceiling: full Kelly assumes a perfectly known edge and tolerates brutal drawdowns. Quarter Kelly or less is the practical reading.

What's a realistic monthly return for a day trader?

From honest inputs (0.25R edge, 3 trades/day, 0.5% risk): roughly 7–8% a month. Consistent single digits compound into an exceptional year.

Fixed dollar or percent risk?

Percent risk compounds and de-risks automatically in drawdowns; fixed dollar keeps sizing stable. A common hybrid: percent risk, recalculated at milestones instead of every trade.