Trading compounding calculator: daily growth table and risk of ruin
Type your balance, win rate, risk per trade and average R. You get the day-by-day table of what compounding promises, and next to it 2,000 simulated paths that show what the same numbers usually do.
Your numbers
R is the amount you risk. An average win of 1.5R with 1% risk means a winner pays 1.5% and a loser costs 1%.
On: risk is a % of the current balance, so position size grows with the account.
Fees are paid on every trade, win or lose. Use the % field for spread and slippage that grow with position size: 5 means 5% of the amount risked.
Withdrawals take this share of each month’s profit at month end; losing months withdraw nothing. Ruin level is the loss from the start that counts as ruin in the simulation.
Adds dates to the table. Weekends are skipped at 5 trading days a week.
Dream line
Risking $100.00 on the next trade? Turn it into a lot size for your stop loss: size this trade →
The settings live in the page address, so the link opens this exact table.
Reality check: 2,000 simulated paths
Same inputs, but each trade is a real win or loss drawn at your win rate. The dream line above is the average of these paths; most traders live near the median, and some in the bottom band.
Prop challenge figure: share of paths that reach +10% before breaking a 5% daily loss or a 10% max loss (both measured from the starting balance) within this period.
2,000 paths simulated in 7 ms in your browser (seeded, so a shared link shows the same numbers).
Day-by-day table
Every trade earns its average. This is the line compounding calculators usually show, and it is the best-behaved month you will never trade.
| Day | Trades | Expected P&L | Fees | Balance | Total |
|---|---|---|---|---|---|
| 1 | 3 | +$112.89 | $9.00 | $10,104 | +1.0% |
| 2 | 3 | +$114.06 | $9.00 | $10,209 | +2.1% |
| 3 | 3 | +$115.25 | $9.00 | $10,315 | +3.2% |
| 4 | 3 | +$116.45 | $9.00 | $10,423 | +4.2% |
| 5 | 3 | +$117.66 | $9.00 | $10,531 | +5.3% |
| 6 | 3 | +$118.89 | $9.00 | $10,641 | +6.4% |
| 7 | 3 | +$120.13 | $9.00 | $10,752 | +7.5% |
| 8 | 3 | +$121.38 | $9.00 | $10,865 | +8.6% |
| 9 | 3 | +$122.65 | $9.00 | $10,978 | +9.8% |
| 10 | 3 | +$123.94 | $9.00 | $11,093 | +10.9% |
| 11 | 3 | +$125.23 | $9.00 | $11,210 | +12.1% |
| 12 | 3 | +$126.55 | $9.00 | $11,327 | +13.3% |
| 13 | 3 | +$127.87 | $9.00 | $11,446 | +14.5% |
| 14 | 3 | +$129.22 | $9.00 | $11,566 | +15.7% |
| 15 | 3 | +$130.57 | $9.00 | $11,688 | +16.9% |
| 16 | 3 | +$131.95 | $9.00 | $11,811 | +18.1% |
| 17 | 3 | +$133.34 | $9.00 | $11,935 | +19.4% |
| 18 | 3 | +$134.74 | $9.00 | $12,061 | +20.6% |
| 19 | 3 | +$136.16 | $9.00 | $12,188 | +21.9% |
| 20 | 3 | +$137.60 | $9.00 | $12,317 | +23.2% |
| 21 | 3 | +$139.05 | $9.00 | $12,447 | +24.5% |
| 22 | 3 | +$140.52 | $9.00 | $12,578 | +25.8% |
A month here is 22 trading days. P&L is before fees; Total includes withdrawals.
Track your real win rate and R instead of guessing
Every number on this page depends on two inputs most traders estimate: win rate and average R. Fips is a trading journal that measures them from your actual trades, with fees, so the next simulation starts from your record.
Private beta: access is by invite from the waitlist. Free plan, no card.
How the maths works
Three ideas: expectancy, compounding, and why the typical result is below the average one.
Expectancy per trade
Expectancy is what one trade earns on average. A win pays your average R, a loss costs 1R, and fees are paid either way. With the defaults (55% win rate, 1.5R, 1% risk on $10,000, a 3.00 fee per trade):
0.55 × 1.5 − 0.45 × 1 = 0.375 R before fees, so $34.50 per trade at the start. The breakeven win rate for 1.5R with that fee is 41.2%: below it, every extra trade loses money on average.
Expected P&L per trade = risk × (win rate × R − (1 − win rate)) − fees
Compounding
With compounding on, the risk is a percentage of the current balance, so each win makes the next position slightly larger. The expected path multiplies the balance by (1 + risk % × edge) on every trade and subtracts the fees.
That is why the default month ends at $12,578 (+25.8%) instead of a straight line: 66 trades at 0.375% each, compounded, minus $198 in fees. With compounding off, the same inputs add the same amount every day.
Why the median is below the dream line
Gains and losses do not cancel in percentage terms. Win 10% and lose 10% and you are at 99, not 100. The more each trade swings the balance, the larger that gap, which is called volatility drag.
So the expected path is the average of all outcomes, pulled up by a few very lucky paths. The middle trader does worse: with the defaults the median of 2,000 simulated months is $12,426, against $12,578 on the dream line, and one path in ten ends below $10,952.
What is realistic
The table is an illustration of your inputs, not a forecast or advice.
Your win rate is an estimate
A 55% win rate measured over 30 trades could easily be 45% over the next 300. Drop the win rate by 10 points in the calculator and watch the table: that is the size of the uncertainty most traders carry.
Edges shrink when you size up
Spread, slippage and commission grow with position size, and fills get worse in fast markets. Put a realistic cost in the fee fields; a small cost per trade compounds against you exactly like the edge compounds for you.
Trades are not independent
The simulation draws each trade independently. Real results cluster: a strategy can stop working for weeks, and traders tilt after losses. Real drawdowns are usually deeper and longer than the median shown here.
Steady monthly returns are rare
Twenty percent a month for a year is a 9× account. Very few traders do that once, and fewer repeat it. Treat a smooth dream table as a check of your assumptions, not as a target.
Risk of ruin: 1% vs 5% per trade
Risk of ruin is the chance that a losing run takes the account below a level you cannot come back from.
Take a thinner edge than the defaults: 45% win rate, 1.5R, 3 trades a day, a 3.00 fee per trade, compounding on, for 6 months. The edge is positive (0.125R before fees), so the dream line rises at any risk size. The question is what each size does to the typical trader.
| Risk per trade | Dream line | Median | 10th percentile | Chance of a 50% drawdown | Median max drawdown |
|---|---|---|---|---|---|
| 1% | $14,864 | $14,258 | $10,213 | 0.0% | 16.1% |
| 2% | $24,854 | $21,529 | $11,097 | 4.1% | 28.8% |
| 5% | $112,726 | $50,462 | $9,733 | 77.7% | 59.3% |
At 1% the median path ends at $14,258 and the chance of a 50% drawdown is 0.0%. At 5% the dream line explodes to $112,726, the median reaches $50,462, and 77.7% of paths go through a 50% drawdown on the way, with $9,733 or less for the unluckiest tenth.
A 50% drawdown needs a 100% gain to recover, and few traders keep following the plan halfway down. That is why common sizing rules of thumb sit between 0.5% and 2% per trade: not because bigger sizes earn less on paper, but because the typical path survives.
Set the ruin level in the calculator to −30%, −50% or a wiped account and change the risk field; the chance of touching it updates for your own numbers.
Prop firm challenge: how many days to +10%?
A common two-step challenge shape: a 10% profit target, a 5% daily loss limit and a 10% maximum loss.
The reality panel above also runs every simulated path through that shape: a path passes when it reaches +10% before its equity drops 5% below the day’s starting level (5% of the initial balance) or 10% below the initial balance. Rules differ by firm, and some measure from equity or trail the high, so treat the result as a first check.
| Win rate | Risk per trade | Pass within 3 months | Breach | Median trading days to +10% |
|---|---|---|---|---|
| 55% | 1% | 99.3% | 0.7% | 8 |
| 55% | 2% | 71.2% | 28.8% | 3 |
| 45% | 1% | 76.1% | 21.1% | 16 |
| 45% | 2% | 41.6% | 58.4% | 3 |
Doubling the risk cuts the days to target sharply, but it also turns three losses in one day into a daily-limit breach. With a 45% win rate, 2% risk breaches more often than it passes. Lower risk with more days is usually the better trade-off when the challenge has no time limit.
Daily loss, max loss and target of each firm, with sources →
Questions
It applies your expected profit per trade to the balance trade after trade, with each risk a percentage of the current balance. With the defaults (10,000, 55% win rate, 1% risk, 1.5R, 3 trades a day, 3.00 fee) that is $34.50 per trade at the start and $12,578 after one month. This calculator adds 2,000 simulated paths next to that expected line, because real results vary around it.
Because percentage gains and losses do not cancel: +10% then −10% leaves you at 99. The expected path is the average of all outcomes and is pulled up by a few lucky runs. With the defaults the median simulated month ends at $12,426, below the dream line at $12,578.
Without fees, 1 / (1 + R): 50% at 1R, 40% at 1.5R, 33.3% at 2R. Fees raise it. With 1.5R and a 3.00 fee on a 100 risk it is 41.2%. The calculator shows the breakeven for your R:R and fees, and says so plainly when your inputs are below it.
The chance that losses take the account below a level you cannot recover from, for example −50% or zero. It depends on the edge, the risk per trade and the number of trades. Here you pick the level (−30%, −50% or a wiped account) and the simulation counts how many paths touch it.
Safer, not safe. In the 45% win rate example on this page, 1% risk gives a median max drawdown of 16.1%, while 5% with the same edge puts 77.7% of paths through a 50% drawdown. With a negative edge no size is safe: the account declines on average whatever you risk.
Fees are paid on every trade: a fixed amount plus an optional percentage of the amount risked. Withdrawals take your chosen share of each month’s profit at month end (a month is 22 trading days at 5 days a week); losing months withdraw nothing. The Total column includes what you withdrew.
Yes. Every input is stored in the page address, so copying the link reproduces the same table, and the seeded simulation shows the same numbers. Nothing is sent to a server and no account is needed.
Illustrative only. The tables and simulations show the arithmetic of the inputs you enter; they are not a forecast, a promise of returns or financial advice. Trading leveraged products carries a high risk of losing money. Past or assumed win rates do not guarantee future results.
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