RSI Indicator Explained: How to Use the Relative Strength Index

Written by Uvin Vindula (IAMUVIN) — Last updated February 2026

Introduction

The Relative Strength Index (RSI) is one of the most popular and widely-used technical indicators in all of trading. Developed by J. Welles Wilder in 1978 and introduced in his book "New Concepts in Technical Trading Systems," the RSI measures the speed and magnitude of recent price changes to evaluate whether an asset is potentially overbought or oversold.

In crypto trading, where volatility is extreme and emotions run high, the RSI provides an objective, mathematical framework for assessing market momentum. However, like all indicators, it has limitations and must be used properly within a broader trading strategy.

What Does RSI Measure?

RSI measures the relative strength of recent gains versus recent losses over a specified period (default: 14 periods). It oscillates between 0 and 100, providing a normalized score of momentum.

The Formula

RSI = 100 - (100 / (1 + RS))

Where RS (Relative Strength) = Average Gain over N periods / Average Loss over N periods

You do not need to calculate this manually — every charting platform computes it automatically. But understanding the math helps you understand what the indicator is actually telling you.

Reading the RSI

Traditional Levels

• Above 70: Traditionally considered "overbought" — the asset may be overextended to the upside and could be due for a pullback.
• Below 30: Traditionally considered "oversold" — the asset may be overextended to the downside and could be due for a bounce.
• Around 50: Neutral — no strong momentum in either direction.

Important Nuances

Here is where many beginners go wrong: overbought does not mean "sell" and oversold does not mean "buy."

• In strong uptrends, RSI can remain above 70 for extended periods. Bitcoin has spent weeks with RSI above 70 during bull runs.
• In strong downtrends, RSI can remain below 30 for extended periods. Selling simply because RSI is overbought during a strong uptrend will cause you to miss significant gains.
• RSI levels indicate momentum extremes, not guaranteed reversal points.

RSI Divergences: The Most Powerful Signal

Divergences between price and RSI are among the most valuable signals the indicator provides.

Bullish Divergence

Price makes a lower low, but RSI makes a higher low. This suggests that bearish momentum is weakening even though price is still falling — a potential reversal signal.

Bearish Divergence

Price makes a higher high, but RSI makes a lower high. This suggests that bullish momentum is weakening even though price is still rising — a potential warning of a downturn.

Hidden Divergences

• Hidden bullish divergence: Price makes a higher low while RSI makes a lower low. Suggests the uptrend will continue.
• Hidden bearish divergence: Price makes a lower high while RSI makes a higher high. Suggests the downtrend will continue.

RSI Settings and Timeframes

Default Setting: 14 Periods

The standard RSI uses 14 periods. On a daily chart, this means 14 days. On a 4-hour chart, 14 four-hour candles (56 hours).

Adjusting the Period

• Shorter period (e.g., 7 or 9): More sensitive, generates more signals, but also more false signals. Better for short-term trading.
• Longer period (e.g., 21 or 25): Less sensitive, fewer signals, but more reliable. Better for swing trading and longer-term analysis.

Timeframe Matters

RSI on a 5-minute chart will give you very different signals than RSI on a weekly chart. Higher timeframe RSI signals are generally more reliable. A good practice is to check RSI on multiple timeframes for confirmation.

Practical RSI Strategies

Strategy 1: RSI Trend Trading

In an uptrend, use RSI dips to the 40-50 range as potential entry points (instead of waiting for 30). In a downtrend, use RSI rallies to the 50-60 range as potential areas of continued selling pressure.

Strategy 2: RSI Range Shifts

During a bull market, RSI tends to oscillate between 40 and 90. During a bear market, RSI tends to oscillate between 10 and 60. Identifying which range RSI is operating in helps you understand the broader market regime.

Strategy 3: RSI with Support and Resistance

Combine RSI readings with key support and resistance levels on the price chart. An oversold RSI reading at a major support level is more significant than an oversold reading at a random price level.

Common RSI Mistakes

1. Buying immediately when RSI hits 30: Oversold can become more oversold. Wait for confirmation of a reversal.
2. Selling immediately when RSI hits 70: In strong trends, this causes premature exits from profitable positions.
3. Using RSI in isolation: RSI should be combined with price action analysis, volume, and other tools — not used as a standalone signal.
4. Ignoring the trend: RSI works differently in trending versus ranging markets. Always identify the trend first.
5. Over-optimizing settings: Constantly changing RSI settings to fit past data leads to curve-fitting, which does not work in live trading.

RSI vs Other Momentum Indicators

Setting Up RSI on TradingView

1. Open TradingView (see our tools page for the link)
2. Open any crypto chart (e.g., BTC/USDT)
3. Click "Indicators" at the top of the chart
4. Search for "RSI" or "Relative Strength Index"
5. Select it to add it below your price chart
6. Adjust settings if needed (default 14 is a good starting point)

Conclusion

The RSI is a powerful and versatile indicator that belongs in every trader's toolkit. However, it is not a magic formula for profitable trading. Use it as one piece of a larger analytical framework that includes price action, volume, support and resistance, and strict risk management.

Practice reading RSI on historical charts before using it in live trading. Over time, you will develop an intuition for how RSI behaves in different market conditions. For more trading education, explore our learning hub.