Knowledge BaseMarket & trading › Relative Strength Index
Market & trading

Relative Strength Index RSI

A momentum oscillator from 0 to 100 that gauges whether a stock may be overbought or oversold.

Part of the Market & Trading Basics course · Lesson 5 of 5
Formula
RSI = 100 − [100 / (1 + (Average Gain / Average Loss))]

What it is

The Relative Strength Index is a technical momentum indicator that measures the speed and size of recent price changes on a 0-to-100 scale. It is typically calculated over 14 periods. Readings above 70 are often called overbought and below 30 oversold, though these are conventions, not rules.

Why it matters

RSI helps traders gauge whether a recent move has been unusually strong in one direction and may be due to pause or reverse. The pitfalls: in a strong trend RSI can stay overbought or oversold for a long time, so it is a context tool rather than a standalone buy or sell signal, and different period settings change the readings.

How it's calculated

Compute the average of up-day gains and down-day losses over the period, take their ratio (relative strength = average gain / average loss), then convert it to a 0–100 scale.

How Quintarthai uses it

Momentum and technical metrics such as RSI are available across the screener and company pages; view a stock on its deep-analysis page.

FAQ

Does an RSI above 70 mean I should sell?
No — overbought just means momentum has been strong; in a powerful uptrend RSI can stay above 70 for a long time without reversing.
What period is RSI usually calculated over?
The standard setting is 14 periods (often 14 days), but traders adjust it; shorter periods make RSI more sensitive and noisier.
Related terms
See Relative Strength Index on a real company
Open any stock in Quintarthai and explore it live across the screener and company pages.
Open the app →