Spread Cost Calculator: Hidden Execution Cost Modeling
Why this page matters
Spread is the first cost paid by every market order. For active systems, cumulative spread can erase theoretical edge even when win-rate looks healthy.
{ Pre-execution checklist }
Baseline and stress spread assumptions are defined.
No-trade spread threshold is configured.
Cost per trade is expressed in both currency and R units.
News and rollover windows have specific execution rules.
Post-trade slippage+spread audit is running.
Calculation logic and practical workflow
Per-trade spread cost formula: Cost = Spread (pips) × Pip Value × Lots.
Example: 1.4 pips × 10 USD × 0.6 lots = 8.40 USD immediate cost.
Weekly cost estimate: Per-trade cost × Number of trades.
If 40 trades/week at 8.40 USD, gross spread cost = 336 USD/week.
Adjust for session variance: spread during rollover/news can be 2-5x baseline.
Build scenario table: baseline spread, stressed spread, and no-trade gate.
Compare spread cost versus average R outcome; if cost consumes too much R, reduce frequency or filter entries.
Common mistakes to avoid
Backtesting with fixed low spread while live market has variable spread spikes.
Ignoring symbol-specific spread regimes across sessions.
Measuring strategy by win-rate only, without net expectancy after costs.