Which timeframe should an Expert Advisor run on?

Why the timeframe changes everything

Indicators and signals are calculated from candles, and a candle on M5 covers a different span of time than one on H1. The same input values, such as a period of 14, describe very different market behaviour depending on the chart.

Use the timeframe the developer tested

The manual or product page normally states the timeframe the EA was designed and tested on. Use exactly that, unless the documentation says the EA is timeframe-independent. Some EAs read a fixed timeframe internally and ignore the chart's one.

Shorter and longer timeframes in general

Shorter timeframes produce more signals and more trades, which makes spread and commission a bigger share of each trade. Longer timeframes produce fewer trades and are less sensitive to small price noise, but each trade is exposed to the market for longer.

• Short timeframes: more trades, more cost sensitivity, more demand on execution quality.
• Longer timeframes: fewer trades, wider stops, less cost sensitivity.

Check your backtest uses the same timeframe

In the Strategy Tester, set the period to the same timeframe you plan to use live. A test on a different timeframe tells you nothing about the live set-up.