Direct answer
In forex, M15 means the chart timeframe where each candle covers 15 minutes of price action. The “M” stands for minutes, and “15” is the duration, so M15 is read as “15-minute candles.”
Explanation: how M15 works
Most forex charting platforms display price as a sequence of candles. On an M15 chart, each candle uses the following idea over a single 15-minute interval:
- Open: the price at the start of the interval
- High: the highest price reached during the interval
- Low: the lowest price reached during the interval
- Close: the price at the end of the interval
When you switch to M15, you are changing the time window used to summarize price. That changes what you see: some movements that look smooth on a longer timeframe can look choppy on M15, and very short swings may create extra “signals” on M15 that are not visible elsewhere. This matters in a mean reversion range context, where the general idea is to look for price behavior that repeatedly moves away from and back toward a typical level range. M15 can be used to observe how quickly price reacts within that range, but it does not guarantee that reversion will happen.
You can also compare M15 to neighboring timeframes (for example, a shorter timeframe or a longer one) to see whether the same broader behavior is being reflected within the 15-minute candles.
Example checks (without predicting outcomes)
Here are simple, independent ways to verify what “M15” means on your chart:
- Set your chart to M15 and count candles: moving forward by 60 minutes should add about 4 M15 candles.
- Inspect the candle timestamps: each candle should correspond to a 15-minute block.
- Look at event timing around a change (such as a news release). If the market moves sharply, the effect should appear across one or more consecutive M15 candles.
These checks confirm the time compression used by the chart rather than the future direction of price.
Relevant limitations and risks
- Timeframe is not a forecast: M15 describes how price is summarized over 15-minute intervals, not what price will do next.
- False interpretation risk: patterns seen on M15 may be influenced by short-term noise. The same behavior can appear different on another timeframe.
- Range behavior is uncertain: in range and mean-reversion thinking, price may or may not return toward typical levels at the time scale you are watching.
Overall, M15 is a 15-minute candle timeframe used to observe market movement with a specific time granularity. Treat observations from M15 as descriptive of what happened within each 15-minute window, not as proof of a particular outcome.