Keep costs from being counted twice
This model starts with a gross reference price move before costs. Actual MT5 entry-to-stop distances and reports may already include bid/ask effects. Do not add spread again to an actual loss or report that already includes it. The calculator is not an exact worst-case stop-loss estimate.
What is excluded?
Swap, financing, currency conversion, minimum ticket charges, gaps and changes in liquidity. Actual stop fills may be worse than requested. Use your broker's actual reports for reconciliation.
Make a useful comparison
Keep the stop assumption fixed, then change only spread or commission. Write down the assumptions with the result. If using the URL to share a scenario, it contains those cost settings but no account number or balance.