RSI lab
Understand what RSI actually measures, and internalise the fact that ruins most people who use it: in a strong trend it stays extreme for months.
Runs entirely in your browserRuns entirely on your device — nothing you type is sent anywhere. Educational only, and not investment advice.
How to use this calculator
Each step names a control you will find on screen above.
- RSI period
The default is 14. Shorten it and the indicator becomes far more volatile, hitting extremes constantly; lengthen it and it barely moves.
- Watch the 70 and 30 lines
Conventionally overbought and oversold. Note how often price keeps going in the same direction after crossing them.
- Find a period of sustained overbought
Look for where RSI stayed above 70 for weeks while price kept rising. This single observation is the most valuable thing on the chart.
- Look for divergence
Price making a higher high while RSI makes a lower high. It is a genuine signal — and it is early, often by months.
Worked example: Why "overbought" is not "sell"
Set the period to 14 and find the strongest uptrend on the chart. Track what RSI does through it.
What to enter
- RSI period
- 14
What it shows you
- RSI crosses 70
- Early in the move
- Price then
- Continues rising for weeks
- RSI through the move
- Stays 70–85
- Selling at the first 70
- Missed most of the trend
- RSI at 7-period
- Hits 70 several times more often
Where this is taught
A calculator gives you a number. These explain what the number means and when it misleads you.
- Technical Analysis11 minDivergence: when price and momentum disagreeOne of the most useful signals in technical analysis and one of the most abused. What it genuinely indicates, and why trading it alone loses money.
- Technical Analysis11 minRSI — relative strength indexWhat RSI measures, why "above 70 means sell" destroys accounts, and the two ways professionals actually use it.
- Technical Analysis8 minThe Chande Momentum Oscillator: raw momentum, unsmoothedThe CMO measures momentum the blunt way — up moves minus down moves over their total — and refuses to smooth the result. That makes it faster and more jagged than the RSI, catching turns earlier at the cost of more noise.
- Technical Analysis12 minCutting false signals without cutting the good onesEvery filter that removes bad trades removes some good ones too. How to measure that trade-off instead of guessing at it.
- Technical Analysis8 minEase of Movement: how hard the volume had to workEase of Movement asks a single question of every bar: how much volume did it take to move the price this far? When price drifts up on light volume, the path of least resistance is up — and this indicator is built to show it.