RSI

The relative strength index (RSI) is a momentum oscillator that measures the speed and change of price movements on a scale from 0 to 100. Developed by J. Welles Wilder, it helps traders identify whether an asset is overbought or oversold and can signal potential reversals. The RSI is widely used across forex, stocks, commodities and indices, and is available as a built‑in indicator on platforms such as MetaTrader 5.

How It Works

The RSI compares the magnitude of recent gains to recent losses over a specified period, most commonly 14 periods. First, the average gain and average loss for the period are calculated. Then the relative strength (RS) is derived by dividing the average gain by the average loss. The RSI formula is:

RSI = 100 − (100 / (1 + RS))

When the average gain exceeds the average loss, RS is greater than 1 and the RSI rises above 50. Conversely, when losses dominate, RS falls below 1 and the RSI drops below 50. Values above 70 traditionally indicate overbought conditions, suggesting the asset may be due for a pullback. Values below 30 indicate oversold conditions, hinting at a possible bounce. Traders also watch for divergence, where price makes a new high or low while the RSI fails to match, signalling weakening momentum.

Why It Matters for Traders

The RSI provides a quick, visual gauge of market strength that can complement other tools like moving averages or the MACD. Because it is bounded, it offers clear thresholds for entry and exit decisions, especially in ranging markets. In trending environments, traders may adjust the overbought/oversold levels (e.g., using 80/20) to avoid false signals. The indicator works on any timeframe, from intraday charts to weekly charts, making it versatile for day traders, swing traders and long‑term investors. When combined with price action or volume analysis, the RSI can improve the timing of trades and help manage risk by highlighting exhaustion points.

Example

Assume a currency pair has the following average gains and losses over the last 14 periods: average gain = 0.45%, average loss = 0.15%. The RS is 0.45 / 0.15 = 3.0. Plugging into the formula gives RSI = 100 − (100 / (1 + 3.0)) = 100 − (100 / 4) = 100 − 25 = 75. An RSI of 75 suggests the pair is approaching overbought territory. A trader might consider tightening stop‑losses or looking for a bearish reversal pattern, especially if the price also shows a bearish divergence on the RSI.

Key Takeaways

• RSI is a 0‑100 momentum oscillator that measures recent gains versus losses.
• Readings above 70 indicate overbought conditions; readings below 30 indicate oversold conditions.
• The indicator is useful for spotting divergence and timing entries/exits, especially when used with other tools like moving averages or price action.
• RSI is available as a standard feature on MetaTrader 5 and can be adapted to different timeframes and market conditions.