RSI
Relative Strength Index — momentum oscillator, 0–100.
What it is
Relative Strength Index — momentum oscillator, 0–100.
The Relative Strength Index (RSI), developed by J. Welles Wilder in 1978, is a bounded momentum oscillator. It compares the magnitude of recent up-closes to the magnitude of recent down-closes over a look-back window (Wilder's default is 14) and rescales the result onto a 0–100 axis.
Conventional reads: above 70 = overbought, below 30 = oversold. In strongly trending markets those thresholds shift (Constance Brown's work argues 40–80 for uptrends and 20–60 for downtrends). RSI is also used to spot divergences — price makes a new high but RSI does not, suggesting weakening momentum.
Wilder used a smoothing scheme equivalent to an EMA with α = 1/N, not the standard EMA α = 2/(N+1). Different platforms use slightly different smoothing, so RSI values can disagree across charting tools.
RSI = 100 - 100 / (1 + RS), where RS = avg gain / avg loss over the look-back window
Read the full Relative strength index (RSI) definition in the glossary →
Live chart
BTC/USDT on Binance with this indicator pre-loaded. Powered by TradingView.
Chart by TradingView. Built-in study shown for illustration; the Noon Barbari engine computes its own values.
Parameters
| Parameter | Default | Range |
|---|---|---|
| Period | 14 | 2 – 800 |
Output fields
The named values this indicator exposes to your entry and exit rules.
Related strategies
Ready-made, runnable templates that use this indicator. Open one to inspect or backtest it.
RSI mean reversion strategy
Buy when the market is overextended below the mean, ride it back to fair value.
Buy-the-dip (Bollinger + RSI) strategy
Two-condition confluence: lower-band stretch AND oversold RSI before taking the dip.
RSI dip with trend filter strategy
Buy oversold RSI dips, but only when price is still above the 50 EMA.
Learn more on the blog
Deep-dive articles explaining this indicator and how to trade it.
How to backtest an RSI strategy on crypto (without fooling yourself)
A step-by-step walkthrough: turn an RSI idea into testable rules, run it on historical crypto data, and tell whether the result is a real edge or curve-fitting.
The RSI indicator, explained properly — most traders use it wrong
RSI 70 is not a sell signal and RSI 30 is not a buy signal. Here's what the Relative Strength Index actually measures, and how to build rules around it that survive a backtest.
Building a mean-reversion strategy with RSI: an end-to-end walkthrough
RSI is one of the most over-used and most misunderstood indicators in retail trading. Here's how to actually build a mean-reversion strategy around it, end to end.
Backtest this indicator
Drop this indicator into a rule-set, run it over years of BTC/USDT data, and see whether the edge is real or just curve-fit — no credit card required.