How to Write a Custom MQL5 Indicator with Consistent Buffer Indexing
Technical revision: 1 October 2026 · Educational materialOn this pageDefine the output and its unitsChoose one array conventionComplete indicator sourceWarm-up, updates and history changesVerify the numbers before interpreting the shapeA useful first custom indicator is the distance between a closing price and its simple moving average. It exposes the central implementation problem: every input array, output buffer and loop must agree on the direction of time. Define the output and its units For each bar, calculate the average of that bar's close and the preceding N-1 closes. Output close - average. A positive value means the close is above its…