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RSI in Forex: How to Use the Relative Strength Index
One of the most popular indicators in the world. Learn to read the RSI correctly, detect divergences and use it to improve your entries.
The RSI (Relative Strength Index) was developed by J. Welles Wilder in 1978. It is one of the most widely used indicators in technical analysis: it measures the speed and magnitude of price movements on a scale from 0 to 100.
How Is the RSI Calculated?
The RSI compares the average gain against the average loss over a period (typically 14 periods):
RSI = 100 - [100 / (1 + RS)]
where RS = Average gain / Average loss (14 periods)
where RS = Average gain / Average loss (14 periods)
Key RSI Zones
- 70+: The asset may be overbought. Signal of a potential bearish reversal or correction.
- 50: RSI above 50 = bullish momentum. RSI below 50 = bearish momentum.
- 30-: The asset may be oversold. Signal of a potential bullish bounce.
RSI Divergences: The Most Powerful Signal
Divergences between price and the RSI are among the most reliable signals the indicator produces. There are two types:
- Bullish divergence: price makes lower lows, but the RSI makes higher lows. Signals a potential upward reversal.
- Bearish divergence: price makes higher highs, but the RSI makes lower highs. Signals a potential downward reversal.
Optimal RSI Settings by Strategy
- Scalping — RSI period: 7 — Timeframe: M1–M5 — Levels: 20 / 80
- Day Trading — RSI period: 14 — Timeframe: M15–H1 — Levels: 30 / 70
- Swing Trading — RSI period: 21 — Timeframe: H4–D1 — Levels: 40 / 60
Combining the RSI with Other Indicators
- RSI + Moving Averages: Confirm trend direction before acting on RSI signals.
- RSI + Support/Resistance: Look for divergences at key price levels.
- RSI + Fibonacci: Divergence at the 61.8% level = high-probability signal.
- RSI + Bollinger Bands: RSI oversold + price at lower band = strong buy signal.
No indicator works 100% of the time. The RSI, like all indicators, regularly produces false signals. Use it as a confirmation tool, not as a complete trading system.
Educational content only. Does not constitute financial or investment advice. Trading involves risk of loss; past results do not guarantee future results.