Stochastic RSI vs Money Flow Index
The stochastic relative strength index applies the stochastic formula to relative strength index values, so every input is a close. The money flow index weights the same kind of momentum calculation by volume, which makes it the only one of the two with a second source of information.
Both are bounded oscillators read for overbought and oversold, and on a chart they look like the same kind of tool. One of them has an input the other cannot see, and that is unusual enough among oscillators to be the reason to care.
What each one is
The stochastic relative strength index runs the stochastic formula over relative strength index values — where the relative strength index sits inside its own recent range, from zero to one hundred. Stochastic RSI covers it, and RSI covers the input.
The money flow index performs a similar momentum calculation weighted by volume, using the typical price of each bar rather than the close alone. The money flow index covers the calculation.
One has two inputs and the other has one. Price and volume against price alone, and whereas most oscillator comparisons are about smoothing or scaling, this one is about whether a second measurement is present at all.
Where they differ
Whether participation is counted. A move on heavy volume and the same move on nothing look identical to the stochastic version. The money flow index separates them, which is the one thing it can say that no price-only oscillator can.
Which part of the bar is used. The money flow index works from the typical price — high, low and close averaged — so the range of the bar is in the calculation. The stochastic version is built on the relative strength index, which uses closes only, so it never sees a wick.
How much derivation sits between price and the number. The money flow index is one step from the bars. The stochastic version is two, and each step amplifies the noise beneath it, which is why it reaches extremes so much more often.
How reliable the input is. Price is price. Volume depends entirely on where you are looking — a single exchange, an aggregate, a contract that rolls — so a volume-weighted tool inherits whatever problems that feed has, whereas a price-only tool has nothing to inherit.
Where they agree
Both are bounded and both pin. In a sustained move each reaches its extreme and stops distinguishing between strong and stronger.
Both are misread as reversal signals. An extreme means the recent move was powerful, and power is what a trend is made of, so the reading shows up at the start of what it is used to bet against.
Both fight the same drift. On this site’s shared series 54% of 566 ten-bar windows finished higher than they started.
And both cost a round trip when acted on — 0.0098 here, about 2% of the median bar range of 0.493.
Which one to use
Run the money flow index when your instrument has trustworthy volume. Stocks and futures do; spot foreign exchange does not, because there is no central tape and the figure your platform shows is one venue’s guess.
Run the stochastic relative strength index when you want fast timing inside a settled condition. In a confirmed range its sensitivity is the point rather than the problem.
Run both when you want a genuine second opinion — this is one of the few oscillator pairs where that phrase means something, because they do not share all their inputs. An extreme on one and not the other is real information rather than a rounding difference.
And when volume on your instrument is unreliable, use the price-only tool and know that is what you are doing. A volume-weighted reading built on a bad feed is worse than no volume reading at all.
Why a second input is rarer than it sounds
Because almost every oscillator on a chart is a transformation of the same closes. Stack three of them and you have one measurement in three colours, which is why they agree so convincingly and why the agreement is worth nothing.
And because the case where the second input matters is the thin one. A move on almost no volume is a move that may not hold, and that is precisely the situation a price-only oscillator reports as strength.
The original data
Of the 24,971 unique videos in the search corpus, no title compares these two directly. The money flow index appears in 44 titles at a median of 3,160 views across 36 channels. The stochastic relative strength index appears in 25, at a median of 26,139 across 23.
Nearly twice the videos and an eighth of the audience. The volume-weighted tool is taught more and sought much less, which is a consistent pattern in this corpus: the indicators that add a second input are less popular than the ones that add another layer to the first.
On the chart above, the disagreement is the signal. A price extreme without a volume extreme means the move happened on thin participation, and that is exactly what the second input exists to tell you.
When it fails
The characteristic failure is trusting the volume weighting on an instrument with no real volume data. Spot foreign exchange is the clearest case: there is no consolidated tape, so the volume your platform draws is one broker’s flow rather than the market’s. Every reading built on that is a measurement of a sample you did not choose and cannot inspect, and it will look perfectly plausible because the tool has no way to signal that its input is unreliable. The price-only oscillator is the honest choice there, whereas on a listed stock the reverse holds.
A second failure is using either as a standalone sell in a trend. Both pin, and pinned describes strength.
A third is reading a divergence as a reversal. A divergence is a description of two lines, not a prediction, and most of them resolve by the indicator catching up.
A fourth is tuning the lookback until the last swing is caught, which fits the sample and nothing after it.
And a fifth is stacking the stochastic version with other price-only oscillators, which is one reading in several colours.
Related
Stochastic RSI covers the twice-derived construction. The money flow index covers the volume weighting. And RSI covers the measure both are related to.
This is one of the few oscillator pairings where running both is defensible, and the reason is narrow: they do not share all their inputs. Most indicator combinations are one measurement drawn twice, and this one genuinely is not.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.