When I use macd line on stock. It is most useful to use 1 min,5min,15 min,half hour or hourly

The choice of time frame for using the MACD line on stocks depends on your trading strategy and the characteristics of the market you are trading. Here are some considerations for each of the time frames you mentioned:

1. **1 minute frame**: This is useful for day traders and scalpers who are looking for short-term price movements. The MACD line can provide quick signals for entering and exiting positions. However, it is important to be aware of the increased noise and potential for false signals that can occur with shorter time frames.
2. **5 minute frame**: This time frame is suitable for traders who prefer shorter-term trades but are not as focused on the immediate price movements as day traders. It can help in identifying trends and potential reversals earlier than the hourly frame.
3. **15 minute frame**: This frame is often used by traders who look for shorter-term trends and are willing to hold positions for a slightly longer period. It can be useful for traders who want to filter out some of the market noise compared to the 1-minute frame while still capturing short-term movements.
4. **Half-hour frame**: This time frame can be useful for traders who are looking for more stable trends and are willing to hold positions for 30 minutes. It can help in identifying stronger trends and filtering out some of the market noise compared to the 1-minute frame.
5. **Hourly frame**: This is a common time frame used by traders who are looking for longer-term trends and are less interested in short-term price fluctuations. It can provide a clearer view of the trend and reduce the impact of market noise.

In conclusion, the choice of time frame for using the MACD line on stocks should be based on your trading strategy, risk tolerance, and the characteristics of the market you are trading. It is often beneficial to experiment with different time frames to find the one that best suits your trading style and objectives.