RSI 14 (Relative Strength Index) measures the speed and size of recent price moves on a 0–100 scale. Above 70 is often seen as overbought, below 30 as oversold.
Where it fits
The Relative Strength Index (RSI) is a momentum oscillator that measures the speed and magnitude of recent price changes on a scale from 0 to 100. Developed by J. Welles Wilder Jr. in 1978, RSI helps identify overbought and oversold conditions, potential trend reversals, and the strength of price movements. The 14-period version is the most commonly used setting.
The RSI calculation involves several steps:
1. Calculate average gains and losses over 14 periods 2. RS (Relative Strength) = Average Gain / Average Loss 3. RSI = 100 - (100 / (1 + RS))
Subsequent calculations use smoothed averages:
Average Gain = (Previous Avg Gain × 13 + Current Gain) / 14 Average Loss = (Previous Avg Loss × 13 + Current Loss) / 14
Traditional interpretation:
- RSI > 70: Overbought; price may have risen too far, too fast
- RSI 50-70: Bullish momentum; uptrend likely intact
- RSI = 50: Neutral; balanced buying/selling pressure
- RSI 30-50: Bearish momentum; downtrend likely intact
- RSI < 30: Oversold; price may have fallen too far, too fast
Key trading applications:
- Overbought/oversold signals: RSI extremes can indicate potential reversal points
- Divergences: When price makes new highs/lows but RSI doesn't confirm, trend may be weakening
- Centerline crossovers: Crossing above/below 50 can confirm trend direction
- Failure swings: RSI patterns that may precede price reversals
Important caveats:
- Extended trends: Stocks can remain overbought or oversold for extended periods in strong trends
- False signals: Overbought doesn't mean "sell immediately"—strong stocks often stay overbought
- Context matters: Adjust thresholds based on market conditions (80/20 in strong trends, 60/40 in ranges)
- Lagging indicator: RSI reflects past price action; it cannot predict future movements
RSI works best combined with other analysis—trend identification, support/resistance levels, and volume confirmation. Use it to add context to trading decisions rather than as a standalone signal generator.