Stochastic RSI (StochRSI): an oscillator of an oscillator

The Stochastic RSI takes the RSI and runs the stochastic formula on it. Instead of asking where today's close sits within the recent price range, it asks where today's RSI sits within the recent RSI range. Tushar Chande and Stanley Kroll introduced it in 1994 to solve a practical complaint: the RSI often spends weeks between 40 and 60 without reaching 70 or 30, so its classic signals rarely fire. StochRSI stretches the RSI's recent swings across the full 0–100 scale.

That stretching makes it extremely sensitive, more so than either ingredient on its own. This guide shows the calculation on real Broadcom data using Finabase's settings, explains why the indicator spends so much time pinned at 0 or 100, and covers how to use it without mistaking its extremes for extremes in price.

What StochRSI measures

The RSI is a measure of momentum: how recent gains compare with recent losses (see Relative Strength Index (RSI): how to read and use it). StochRSI is a measure of momentum of the momentum reading: is the RSI currently near the top or the bottom of its own recent range?

• StochRSI 100: RSI is at its highest value of the look-back.
• StochRSI 0: RSI is at its lowest value of the look-back.
• StochRSI 50: RSI is halfway between its recent high and low.

Nothing in that says whether the RSI itself is high or low. An RSI of 60 can produce a StochRSI of 0 if the previous four RSI readings were all higher, which is exactly what happened on Broadcom in May 2026.

The formula

Many platforms use 14 for both the RSI and the stochastic look-back (14, 14, 3, 3). Finabase's 14, 5, 3 compares each RSI value with only the last five, so it reacts much faster.

A worked example on Broadcom

Here are Broadcom's (AVGO) RSI (14) values for the five sessions ending May 7, 2026, from Finabase's chart.

StochRSI on May 7 = (60.04 − 60.04) ÷ (69.28 − 60.04) × 100 = 0.

A day earlier, with May 6's RSI of 68.01 inside a window whose low was 65.93 and high 69.28, StochRSI was (68.01 − 65.93) ÷ (69.28 − 65.93) × 100 ≈ 62. One 3% down day moved the indicator from 62 to 0. The RSI itself only dropped from 68 to 60, still well above 50. The day after, Broadcom rose 4.2% and StochRSI bounced to 63.

StochRSI on a real chart

Over the six months to October 29, 2026, Broadcom rose to a high of $495.00 on June 3, then fell to $345.00, down 17.4% for the period. Its RSI never went below 30 and was above 70 on only two days. By the classic RSI rules, almost nothing happened.

StochRSI, by contrast, was constantly at its extremes:

• %K was exactly 0 on 36 sessions and exactly 100 on 34, out of 127.
• It was below 20 on 53 sessions and above 80 on 44.

The June top shows both its speed and its limits. On June 1 and 2, as Broadcom rallied to $481.57, %K and %D were both at 100. On June 4 the stock fell 12.6% in a day, the RSI dropped from 73 to 48, and %K went straight to 0. StochRSI reported the collapse instantly, but only after it had happened; it gave no warning on June 3, when %K was still 91.

Taken as a simple rule, buying when %K crossed back above 20 fired 17 times. Of the 16 with five sessions of data after them, ten were higher five sessions later, and their average five-day return was +1.2%, in a period when the stock fell 17%. That is a modest edge for short-term timing, from a small sample, not a strategy.

How traders use StochRSI

Short-term timing. Its main use is to time entries within a trend identified elsewhere: in an uptrend, wait for StochRSI to drop to the bottom of its range and turn up; in a downtrend, wait for it to reach the top and turn down.

Getting signals when RSI is quiet. When the RSI drifts between 40 and 60, StochRSI still swings fully, highlighting the small turns in momentum that the RSI hides.

%K and %D crossovers. As with the regular stochastic, %K crossing %D is the trigger, and crosses near the extremes carry more weight than crosses in the middle.

Pitfalls and limitations

Extremes are relative. A StochRSI of 0 says the RSI is the lowest it has been in a few days, not that the stock is oversold. On May 7, 2026 Broadcom's RSI was 60.

Very noisy at short look-backs. With Finabase's 5-bar look-back, one strong day can take it from one extreme to the other. A 14-bar look-back smooths that considerably.

Double processing. StochRSI inherits the RSI's lag and adds the stochastic's sensitivity. Its readings can flip faster than any decision based on them.

Comparison table

See Stochastic oscillator (slow %K and %D): how to read it and Fast stochastic oscillator: raw %K, %D and its whipsaws for the price-based versions.

How Finabase calculates and scores StochRSI

Finabase computes the Stochastic RSI with TA-Lib's STOCHRSI function on closing prices. The study is titled STOCHRSI 14 %K(5) %D(3): a 14-period RSI, a 5-period stochastic look-back for %K and a 3-period simple average for %D, all adjustable. It is drawn in its own panel with guide lines at 20, 50 and 80.

StochRSI appears in the technical gauge on the symbol page with its latest %K value but carries no Buy or Sell rule, so it always counts as neutral. That is a reasonable choice for an indicator that spends half its time at 0 or 100.

Frequently asked questions

What is the difference between RSI and Stochastic RSI?

RSI measures momentum from average gains and losses on a 0–100 scale. StochRSI measures where the current RSI sits within its own recent range. It is far more sensitive and reaches its extremes much more often.

What are the best StochRSI settings?

Chande and Kroll used 14 for both the RSI and the look-back. Finabase defaults to 14, 5 and 3, which is faster. Longer look-backs give fewer, steadier signals.

Why is my StochRSI stuck at 0 or 100?

Because the current RSI is the lowest or highest in the look-back window. With a short window that happens often: on Broadcom's chart, on 70 of 127 sessions.

Summary

The Stochastic RSI rescales the RSI to the range of its own recent values, turning small swings in momentum into full 0-to-100 moves. With Finabase's 14/5/3 setting it is very fast: Broadcom's StochRSI sat at exactly 0 or 100 on more than half the sessions in six months, and read 0 on a day when the RSI was 60. Use it to time short-term entries in the direction of a confirmed trend, and always read it with the RSI underneath.