Rules Guide — everything the simulator computes.
This document explains exactly how every rule in FundCalc Pro works —
step by step, with example trades, numbers and calculations. Ideal for understanding exactly what the simulator does and why the results look the way they do.
What the simulator does
FundCalc Pro runs many independent random trading scenarios. Each simulation starts with the same starting balance, but wins and losses are generated randomly based on the given Win Rate. The result is a statistical distribution of possible outcomes — best, average, and worst-case scenario.
One trade in the simulation
Important notes on the model
!
Every trade is statistically independent — there is no correlation between trades.
!
Win Rate doesn't change during the simulation — the simulator doesn't model market regimes.
!
With fixed RR, every win has the same set R. When you enable Dynamic RR the win value is drawn from the given range. Each loss is the standard −1R.
!
Fees and slippage are accounted for only through RLD.
!
Results are a probabilistic estimate, not a prediction of the future.
Step by step
1
The current risk is computed (fixed $, or % of balance for Dynamic Risk)
2
The effective TP is computed after subtracting the RLD penalty
3
A WIN or LOSS is generated (random number vs Win Rate)
4
Balance goes up (WIN) or down (LOSS)
5
For a Live account: a negative balance is capped at $0
6
The result is added to the daily P&L
7
The peak is updated (if the balance is higher than the previous maximum)
8
The current drawdown from peak (or from start) is computed
9
The DD Threshold is checked (drawdown from peak)
10
DD Lock activation is checked
11
The current floor is computed based on the DD type
12
Determines whether the end of the trading day has been reached
13
At the end of the day, the daily profit is saved for the Consistency Rule
14
Bust check — takes priority over the pass check
15
Pass check + Consistency Rule (only after the target is reached)
16
If neither bust nor pass → the next trade continues
17
After reaching the maximum number of trades → timeout
⚠ The bust check always takes priority over the Pass check. If the balance hits both the floor and the target on a single trade, the simulation is counted as a bust.
Trailing DD is the most common type at top prop firms (FTMO, Alpha Capital…). The floor (lower bound) rises with the peak — never drops.
How it works step by step
1
Initial settings
Account = $100 000, Max DD = $10 000.
Initial floor = $100 000 − $10 000 = $90 000.
Peak = $100 000.
2
Each trade — update the peak
After each trade: if balance > peak → the peak updates to the new value. Floor = peak − $10 000.
3
Floor rises, never falls
When you earn $5,000, the peak = $105 000 → floor = $95,000. If you then take a loss, the floor stays at $95,000 — never drops back.
4
Bust = balance ≤ floor
On every trade it checks: balance ≤ floor → instant bust. The check runs after each individual trade.
Example — Trailing DD with a $100k account, $10k DD
| # | Result | P&L | Balance | Peak | Floor | Status |
|---|
| Start | — | — | $100,000 | $100,000 | $90,000 | OK |
| 1 | WIN +1.5R | +$1,500 | $101,500 | $101,500 | $91,500 | OK ↑ floor rose |
| 2 | WIN +1.5R | +$1,500 | $103,000 | $103,000 | $93,000 | OK ↑ floor rose |
| 3 | LOSS -1R | -$1,000 | $102,000 | $103,000 | $93,000 | OK (the peak doesn't change) |
| 4 | LOSS -1R | -$1,000 | $101,000 | $103,000 | $93,000 | OK |
| 5 | WIN +1.5R | +$1,500 | $102,500 | $103,000 | $93,000 | OK (peak stays $103k) |
⚠ Key effect: The more you earn, the less room you have to lose. If you reach $110,000, the floor sits at $100,000 — and all your original DD room is gone. That's why Trailing DD is the strictest type.
🔒 Not available yet — fine-tuning: EOD drawdown isn't finished yet, so it's temporarily disabled in the app everywhere — in the main Simulator and in Comparison of simulations. The section below explains how EOD works and how the engine computes it, once we enable it. Until then, use Trailing or Fixed.
EOD DD checks your position only once a day — at the end of the trading day. Intraday you can go deep into losses; all that matters is where you end up in the evening.
How it works step by step
1
Floor is fixed for the whole day
Floor = $100 000 − $10 000 = $90 000. It doesn't change during the day — it's only checked at the end of the day.
2
Intraday losses are allowed
If you go to $89,000 during the day (below the floor), the simulation doesn't bust. Still trading.
3
End of day check
After the last trade of the day: balance ≤ floor → bust. If you're back above the floor, you keep going.
Example — EOD DD, 5 trades per day
| # | Result | Balance | Floor | End of day? | Status |
|---|
| 1 | LOSS | $99,000 | $90,000 | Ne | OK (intraday) |
| 2 | LOSS | $98,000 | $90,000 | Ne | OK |
| 3 | LOSS | $97,000 | $90,000 | Ne | OK — with Trailing it would be a bust! |
| 4 | WIN | $98,500 | $90,000 | Ne | OK |
| 5 | WIN | $100,000 | $90,000 | YES | OK — above floor ✓ |
✓ Advantage of simplified EOD: Allows recovery — if you have a bad morning but bounce back in the afternoon, you survive the day.
⚠ Careful with interpretation: It's about simplified model — the floor is fixed (Account − Max DD) and is only checked at the end of the day. Real prop firm EOD/trailing systems vary by program: their floor typically rises with the highest daily balance, and violations are often tracked in real time (including unrealized P&L). Always verify the specific program's current rules before a live challenge.
Fixed DD is the simplest type. The floor is set at the start and never moves — no matter how much you earn.
How it works
1
The floor is set once and for all
Floor = $100 000 − $10 000 = $90 000. This value never changes, regardless of how high the balance goes.
2
You make $50,000 — floor still $90,000
If you go for $150,000, the floor stays at $90,000. You have $60,000 of room to lose — that's 6× more than the original DD limit!
3
Bust = balance ≤ $90 000
Simple — if balance falls to or below $90,000 at any point, it's a bust.
Comparison of three DD types — same parameters ($100k, $10k DD)
| Situation | Trailing DD | EOD DD | Fixed DD |
|---|
| Start — Floor | $90,000 | $90,000 | $90,000 |
| After $10k profit — Floor | $100,000 ↑ | $90,000 (fixed) | $90,000 (fixed) |
| After $50k profit — Floor | $140,000 ↑ | $90,000 | $90,000 |
| Intraday bust possible? | YES | NO | YES |
| Typical firms | FTMO, Alpha | Topstep, Apex | Smaller firms |
| Bust rate (55% WR, 1.5R) | ~3% | ~1% | ~2% |
DD Lock solves the biggest drawback of Trailing DD — that the floor rises indefinitely. You set a threshold, and once it's reached the floor "locks" at a fixed value (default = account size; you can enter a custom one in the app DD Lock Floor).
How it works step by step
1
Set Lock threshold
Example: Account $100,000, Lock at $110,000. Trailing DD works normally until balance reaches $110,000.
2
Balance reaches $110,000 — LOCK!
The moment balance ≥ $110,000, the floor locks at $100 000 (default = account size; a custom value can be set in the DD Lock Floor field). From this point on, the floor never rises.
3
Protects profit
After the lock, you always have $10,000 (or more) of room below your current balance, regardless of peak. This matches the real behavior of funded firms after a successful challenge.
Example — Trailing DD Lock at $110,000
| # | Balance | Peak | Floor | Lock active? |
|---|
| Start | $100,000 | $100,000 | $90,000 | Ne |
| After 5 WIN | $107,500 | $107,500 | $97,500 | Ne |
| WIN → $110,000 | $110,000 | $110,000 | $100,000 🔒 | YES — LOCKED! |
| Next WIN | $111,500 | $111,500 | $100,000 | YES (the floor doesn't move) |
| 3× LOSS | $108,500 | $111,500 | $100,000 | YES — still safe |
✓ Practical tip: Setting the Lock threshold at the Profit Target level mainly makes sense when the simulation, after reaching the target, continues — for example due to the Consistency Rule or in the mode Without a profit target. On an instant PASS (the challenge is met on the same trade that reaches the target), the DD Lock no longer affects the outcome.
Normally the simulation ends as soon as the balance reaches the Profit Target. Without a profit target the simulation keeps running — until a bust occurs or you use up the maximum number of trades.
How it works
1
Profit Target = infinity
Internally: target = ∞. The balance can go arbitrarily high — the simulation never "fails", we keep going.
2
The only exit = bust or timeout
The simulation ends only if: (a) the balance falls to the floor (bust), or (b) it reaches the max number of trades (timeout).
3
KPIs change
Instead of Pass Rate you see the distribution of final balances — Top 10%, Average, Bottom 10%. This tells you how the strategy performs over the long run.
When to use
Challenge simulation: Leave Profit Target on — you want to know how fast you'll pass.
Funded account simulation: Check "Without a profit target" — you simulate how the strategy behaves on a live funded account where you trade indefinitely and only care whether the drawdown limit knocks you out.
What is a Live account
The Live account simulates trading with your own capital — no challenge, no profit target, no prop firm DD limit. The only bust condition is losing the entire account.
Difference: Live account vs No profit target
| Property | Live account | Without a profit target |
|---|
| Floor | $0 (loss of the entire account) | Prop firm DD floor |
| Bust condition | balance ≤ $0 | balance ≤ trailing/fixed floor |
| Profit Target | none | none |
| Pass Rate | N/A | N/A |
| Consistency Rule | no effect | no effect |
| Result metrics | average balance, bust rate | average balance, bust rate |
What a Live account can use
✓
Dynamic Risk — % of current balance
✓
Real Life Delay — penalty at TP
✓
Profit target — tracks how many simulations reached the given profit level
✓
DD Threshold — tracks psychological drawdowns
✗
Consistency Rule — no effect (no challenge pass)
✗
Trailing/Fixed/EOD DD floor — the floor is always $0
Note on Dynamic Risk and the Live account
With Dynamic Risk and a Live account, the balance can mathematically decline very slowly, because risk shrinks along with the balance. Still, a bust isn't impossible — with an extremely unfavorable streak or settings, the balance can reach zero.
🔒 Coming soon: The daily loss limit is still locked in the Simulator (\"coming soon") — the toggle can't be turned on, so no simulation actually uses it right now. The section below describes exactly how it will work once we enable it.
Besides the total DD limit, many prop firms also have a daily limit — the maximum loss in a single trading day. If you exceed it, the day is a bust.
How it works step by step
1
You set % of the account
Example: 5% of $100,000 = $5,000 max daily loss. The simulator tracks each day's P&L separately.
2
Calculated at the end of each day
How many trades are "one day" depends on Trades/month. At 20 trades/month = 1 trade/day. At 100 trades/month = ~5 trades/day.
3
Limit exceeded = instant bust
If the daily loss exceeds the limit, the simulation stops (bust) — regardless of total DD.
Example — Daily limit 5% ($5,000), 5 trades/day, risk $1,500/trade
| # | Trade | P&L | Daily P&L | Limit | Status |
|---|
| 1 | LOSS | -$1,500 | -$1,500 | -$5,000 | OK |
| 2 | LOSS | -$1,500 | -$3,000 | -$5,000 | OK |
| 3 | LOSS | -$1,500 | -$4,500 | -$5,000 | OK — barely |
| 4 | LOSS | -$1,500 | -$6,000 | -$5,000 | BUST — limit exceeded! |
⚠ Watch your settings: The daily limit works with all DD types. If you have a high-frequency strategy (many trades/day), a small daily limit can bust you much sooner than the overall DD limit.
Index of the loss that triggers the bust = ceil(Daily limit $ / Risk per trade $)
Number of losses a day can safely survive = ceil(Daily limit $ / Risk per trade $) − 1
Example: limit $5,000, risk $1,500 → ceil(3.33) = 4 → you survive 3 losses (−$4,500), the 4th loss (−$6,000) = bust
Bust occurs as soon as the daily loss reaches or exceeds limit.
The Consistency Rule prevents passing the challenge on a single extremely good day. Your best day can't make up more than X% of total profit.
Formula — Consistency Score
Consistency Score = (Best day profit / Total profit) × 100
Pass condition: Score ≤ the set limit (e.g. 30%)
How it works in the simulation
1
Balance reaches Profit Target
Normally this would be a PASS. But with the Consistency Rule on, the score is checked first.
2
Consistency Score calculation
The simulator tracks each day's profit. It finds the best day and divides it by total profit. If > limit → can't pass yet.
3
Keep trading — until the score is OK
The trader must keep trading (and spread profits across more days) until the Consistency Score drops below the limit. This extends the time to pass — but also raises the risk of bust.
Example — Consistency Rule 30%, Target $10,000
Scenario A — WON'T PASS:
Day 1: +$6,000 | Day 2: +$2,000 | Day 3: +$2,000 | Total: $10,000
Score = $6,000 / $10,000 × 100 = 60% → FAIL (limit is 30%)
Scenario B — PASSES:
Day 1: +$3,000 | Day 2: +$3,000 | Day 3: +$2,500 | Day 4: +$1,500 | Total: $10,000
Score = $3,000 / $10,000 × 100 = 30% → PASS ✓
⚠ Impact on simulation: The Consistency Rule lengthens the time to pass and raises the bust rate, because the trader has to trade longer and gets more chances to bust. The exact impact depends on your parameters — run the simulation with your own numbers.
The Monte Carlo simulation assumes ideal execution. Real Life Delay lowers the reward of every winning trade — simulates reality: slippage, late entries, early exits, emotions. Loss stays at the standard −1R.
How it works
1
Set penalty in R
Example: TP = 1.5R, penalty = 0.1R → effective TP = 1.4R. Each win brings 0.1R less.
2
The penalty is applied to every WIN
Win P&L = Risk × (TP − penalty). Loss stays the same (−1R × Risk). Effectively lowers Profit Factor and EV per trade.
3
Recalculates the break-even win rate
With the penalty, the win rate needed to break even goes up. You get a realistic picture of how the strategy performs in practice.
Impact of the penalty on key metrics (55% WR, Risk $1,000)
| Penalty | Effective TP | Win P&L | EV/trade | Break-even WR | Pass Rate* |
|---|
| None (ideal) | 1.5R | $1,500 | +$375 | 40.0% | 97% |
| −0.1R (small) | 1.4R | $1,400 | +$320 | 41.7% | 95% |
| −0.3R (medium) | 1.2R | $1,200 | +$210 | 45.5% | 91% |
| −0.5R (large) | 1.0R | $1,000 | +$100 | 50.0% | 76% |
| −0.7R (critical) | 0.8R | $800 | -$10 | 55.6% | 45% |
* Approximate values at 5,000 simulations, $100k account, $10k target, Trailing DD
What each penalty level models
0.05–0.1R — Light slippage, very good execution. Almost ideal conditions.
0.1–0.2R — Normal slippage + occasional late entry. Realistic for most traders.
0.2–0.4R — Worse execution, emotional trading, crowded sessions.
0.5R+ — Serious execution problems or RR worse than planned.
Break-even WR with RLD = 1 / (1 + TP − penalty)
Example: TP=1.5R, penalty=0.3R → BE WR = 1/(1+1.2) = 45.5%
EV per trade = WR × (Risk × effective TP) − (1−WR) × Risk
Example: 0.55 × $1,200 − 0.45 × $1,000 = $660 − $450 = $210
Which rule → which setting in the simulator
⚠ Rules differ by firm, account type, and purchase date and change over time. That's why we deliberately don't name specific firms — always verify the current terms of your program directly with the firm before simulating. Below is a guide on how to map each type of rule onto the simulator.
| Firm rule | How to set it up in FundCalc |
|---|
| Trailing drawdown (floor rises with the peak) | Type DD = Trailing |
| Static / fixed max loss | Type DD = Fixed |
| Trailing that stops after a pass | Trailing + DD Lock at the target level |
| Consistency target (e.g. 30–50 %) | Turn on Consistency Rule and set % |
| Daily loss limit | Daily loss limit (still "coming soon") |
| Slippage / worse execution | Real Life Delay 0.05–0.2R |
| Own / live capital | Live account or Without a profit target + Fixed |
Impact of combinations on Pass Rate
Each added rule lowers the Pass Rate. Example: WR 55%, Risk 1%, TP 1.5R, Trailing DD 10%:
| Rules | Relative Pass Rate | Impact |
|---|
| Only Trailing DD | highest | base |
| + Daily Limit | lower | falls |
| + Consistency | even lower | falls |
| + RLD | even lower | falls |
| All rules | lowest | largest drawdown |
⚠ The impact of each rule depends on WR, TP, risk, target, DD and simulation length. The real impact depends on your WR, TP and Risk per trade. Always run a simulation with your own parameters.
Recommended combinations for testing
1
Base scenario
Trailing DD with no other rules — see your strategy's pure Pass Rate without the influence of prop firm rules.
2
Realistic scenario
Trailing DD + Daily Limit + RLD 0.1R — the most common combination at modern prop firms.
3
Conservative scenario
Trailing DD + Daily Limit + Consistency + RLD — the strictest variant. A higher Pass Rate means a higher probability of passing under the specific given conditions — on its own, though, it doesn't prove the strategy is robust (it's also affected by risk, target, DD, and the number of trades).
4
Real capital
On a Live account the floor is always $0 (bust only at zero), and choosing Trailing/Fixed/EOD has no effect here. For a personal loss cap, turn on Drop from peak → Stop the simulation. If you want a static personal floor, use Without a profit target + Fixed DD.
⚠ Daily loss limit is still "coming soon" — scenarios 2 and 3 (which include it) can be set up this way only once it's enabled. Until then, run them without the Daily Limit.
What is Dynamic Risk
Instead of a fixed Risk per trade ($), the simulator computes risk on each trade as a percentage of the current balance. Your risk grows with wins and shrinks with losses — so-called Fixed fractional risk (a fixed percentage of the current balance). The Kelly criterion is used in the simulator only as an informational calculation in the Mini WR calculator — Dynamic Risk does not use the Kelly value automatically.
Pros and cons
| Edge | Disadvantage |
|---|
| Profit automatically grows on wins | During a losing streak it shrinks position size → slower recovery |
| Natural capital protection | A bust to $0 is very unlikely but not impossible — the minimum risk is $1, so the account can very slowly drift toward zero |
| Realistic simulation of active money management | More complex interpretation of results |
Few strategies have a single fixed Take Profit — sometimes you close at +1.5R, other times it runs to +3R. Dynamic RR simulates exactly this: on each trade it draws the reward:risk ratio randomly from a range you set (⟨min R, max R⟩). Risk stays the same, only the reward changes.
How it works
You check "Dynamic RR" and you enter a minimum and maximum R (e.g. 1.0 to 3.0). For each trade, the simulator then draws a random number from this range (uniform distribution) and uses it as the reward for that specific trade. Win rate doesn't change one bit — only how much a winning position earns changes.
The same range in all calculations
The random R is drawn from of the same range in the main simulation, in the Risk of Ruin calculation, and in the distribution chart (PDF). This keeps Pass Rate, Risk of Ruin, and result variance in sync so they don't show contradictory numbers. For rough estimates (break-even WR, EV, previews) it uses middle of the range as a representative R.
⚠ Caution when combined with Real Life Delay: When both Dynamic RR and RLD are on, the penalty is checked against the minimum R, not against the average. The penalty must be smaller than the smallest possible reward — otherwise the worst trades would end with zero or negative returns.
✓ When to enable it: Dynamic RR has higher variance than fixed R — individual simulations differ more from one another. It's useful when your real-world outcomes fluctuate and you want to see a more realistic spread of passes and busts instead of a smoothed-out average.
How it works
On every trade the simulator tracks the current drawdown from the running peak. If the drawdown exceeds the set threshold, the simulation records it.
If you set the threshold to 10%, this simulation would be flagged as "reached a drawdown". The resulting KPI card shows what % of all simulations experienced such a drawdown.
When to use
📊
Psychological drawdown
Set the threshold to 10–15% to find out how often your strategy triggers psychologically tough periods even when you ultimately pass.
🏦
Risk management — real capital
Set the threshold to your personal DD limit (e.g. 20%) and find out the probability of triggering an account-wide stop-loss.
What the Profit target does
The profit target is statistical metric only — doesn't end the simulation, changes neither pass nor bust. The simulator tracks whether peak balance ever reached the specified level above the starting balance during the simulation.
Result metric
⚠ Profit Target ≠ Profit Goal
Profit Target = ends the challenge as PASS (pass condition)
Profit target = tracks how many simulations ever reached the given value (doesn't affect the simulation)
Entering the Profit Goal
Enter only the profit amount, not the target account balance.
Model doesn't include
| Factor not included | How to account for it |
|---|
| Win Rate changing over time | Run multiple simulations with different WR |
| Alternating market regimes | Simulate each mode separately |
| Correlation between trades | Not available in the current version |
| Varying win sizes | Turn on Dynamic RR — draws R from the range ⟨min, max⟩ |
| Different loss sizes (other than −1R) | The current version doesn't separately model |
| Spread, commissions, overnight fees | Subtract from TP or add to RLD |
| Slippage as a random distribution | Estimate the average slippage and set RLD |
| Psychological mistakes | Account for it with RLD or a lower WR |
| Minimum number of profitable days | A specific prop firm's rule — not in the model |
| Prop firm payout rules | Verify directly with the firm |
A Monte Carlo result is no guarantee of future results. It shows a distribution of possible scenarios based on your assumptions — not the actual market.
Offline mode
The calculation engine itself works without an internet connection. In the current HTML version, however, charts and fonts may require an internet connection (Chart.js and Google Fonts load from a CDN). Simulation results are available offline, but the charts may not display.
EV, Profit Factor and Kelly %
Time — medians and percentiles
Floor and DD limits — exact calculations
Consistency Rule — exact calculation
Real Life Delay — exact calculation
Daily loss limit — exact calculation
Monte Carlo method — how the simulation works
📌 FundCalc Pro uses Math.random() — the browser's pseudo-random generator. It's not cryptographically secure and results can't be reproduced with the same seed. It's fine for Monte Carlo estimates. The PDF Risk of Ruin proof uses a deterministic seeded generator (LCG, seed=42) — results are reproducible.
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