Required Win Rate For Payoff Ratio
The standard formula for breakeven win rate at a given reward:risk ratio, p = 1 / (1 + R), is the number most traders learn first and the number this script deliberately does not stop at. It assumes every winning trade banks the full reward and every losing trade costs exactly the risk, with nothing else changing hands - no spread, no commission. Real trading has both, on every single trade, win or lose, and that changes the win rate actually required to break even. This script reads the symbol's live spread and combines it with a manually entered commission figure to compute the true per-trade drag, then solves the same breakeven equation with that drag included: the win rate needed is (risk + drag) / ((reward + risk)), not the frictionless 1 / (1 + R). The gap between the two is printed as its own column, because that gap is usually the part a trader has no real intuition for - a 2:1 setup that looks like it only needs a 33% win rate can easily need several points more once real costs are in the calculation, and at tight stops on a wide-spread symbol the gap is substantial. The table spans a configurable range of reward:risk ratios in one run, so the whole trade-off curve is visible at once rather than one ratio at a time. Notes and limitations - Spread is read live at the moment the script runs and varies through the trading day. Run it during your normal trading hours for a representative figure, not immediately after a news release when spreads widen. - The result is independent of lot size - costs and risk are both computed per lot, so the ratio between them, which is what the formula needs, holds at any position size. - Slippage is not included. A broker with frequent negative slippage adds a further, unpredictable drag this table does not attempt to estimate. - A row marked unreachable means the real win rate required exceeds 100% at that stop distance and cost level - the setup cannot break even as specified, regardless of edge.
Script · MT4 · v1.0 · Free
About Required Win Rate For Payoff Ratio
Required Win Rate For Payoff Ratio is a script for MetaTrader 4. It can alert you with a pop-up, sound, email or push message. It has 8 settings, such as Symbol, Stop loss pips and Commission per lot round turn. MQL source code included.
Files in the download: RequiredWinRateCalculator.ex4, RequiredWinRateCalculator.mq4, RequiredWinRateCalculator.txt.
Settings
| Setting | Default | What it does |
|---|---|---|
| Symbol | Symbol ("" = this chart's symbol) | |
| Stop loss pips | 20.0 | Stop-loss distance used for the cost calculation, pips |
| Commission per lot round turn | 0.0 | Commission, one round turn, account currency per lot |
| Risk reward min | 0.5 | Table start, reward:risk ratio |
| Risk reward max | 3.0 | Table end, reward:risk ratio |
| Risk reward step | 0.25 | Table step, reward:risk ratio |
| Export csv | false | Also write the table to a CSV file |
| Csv delimiter | , | CSV delimiter (first character is used) |
How to install
- Download the ZIP from your PolyMaria library and unzip it.
- In MetaTrader 4 open File → Open Data Folder, then go to MQL4 → Scripts.
- Copy the .mq4 file(s) there. Put any .mqh files in MQL4 → Include.
- Open the .mq4 file in MetaEditor and press Compile (F7) if MetaTrader does not show it.
- Drag the script onto a chart to run it once.
Tags: Trailing Stop & Break-even · Alerts · MT4 Script · MQL4 Source Code