What Is the Money Flow Index and What Does It Tell You?

The Money Flow Index (MFI) is an oscillator that weighs each day's price move by its volume, so it tells you how strong buying or selling pressure has been. It's also known as a volume-weighted RSI. Textbooks call a reading above 80 overbought and one below 20 oversold.

Our test covered 26 Phemex crypto perpetuals other than BTC and ETH from May 2024 to October 2026. A fresh MFI close under 20 came before a higher close ten days later about 59% of the time, against 45% of all days. BTC and ETH crossed the 80 and 20 lines only 19 times, too few to show an edge either way.

The Money Flow Index at a Glance

What Is the Money Flow Index?

Gene Quong and Avrum Soudack built the Money Flow Index by taking the formula of the Relative Strength Index (RSI) and adding volume. A day that rises on heavy trading counts for more than one that rises on thin trading. The index follows money moving in and out as well as price.

The MFI indicator keeps the 0-to-100 scale of the RSI, which J. Welles Wilder built from closing prices alone.

ChartSchool describes the MFI as an oscillator that uses price and volume to measure buying and selling pressure.

How Is the Money Flow Index Calculated?

The money flow index formula takes four steps, each built from a day's price range and its volume.

1. Work out the typical price, the day's high plus low plus close, divided by three.

2. Multiply the typical price by the day's volume to get its raw money flow.

3. Add up 14 days of flow on days whose typical price rose (positive flow) and on days it fell (negative flow).

4. Divide positive flow by the total of both and multiply by 100.

A day with an unchanged typical price counts in neither sum. Wikipedia's money flow index entry gives that last step the plain way, as "a percentage of positive money flow to total money flow." ChartSchool runs the same two sums through RSI's formula. Both routes give the same reading.

A Worked Example on BTC

Phemex's BTC perpetual gave a clean example on 7 September 2024. Over the two weeks of daily bars ending that day, positive flow came to about 540 million USDT and negative flow to about 2.46 billion.

Positive flow was about 18% of the total, so the MFI closed at 18, down from almost 22 the day before.

That made it a fresh close under 20, the signal tested below. BTC closed that day at 54,136.8 and ten days later stood about 11% higher.

What Does the Money Flow Index Tell You?

The Money Flow Index tells you how much of the recent money flow came on up days. Textbooks turn that into three kinds of signal you can watch for.

Overbought and Oversold at 80 and 20

ChartSchool's rule of thumb is that "typically, MFI above 80 is considered overbought and MFI below 20 is considered oversold." It adds the warning traders tend to forget, that "MFI can become overbought (>80) and prices can simply continue higher when the uptrend is strong."

Quong and Soudack recommended wider lines to qualify the signal further. "A move above 90 is truly overbought, and a move below 10 is truly oversold," ChartSchool writes.

Those lines were rare on Bitcoin. BTC's MFI never closed beyond either one on Phemex's daily bars from February 2024 to the early-November close, and it came closest to 10 in August 2024. ETH's topped 90 on three days in July 2025.

Divergences and Failure Swings

A bullish divergence forms when price makes a lower low and the MFI makes a higher low, which ChartSchool reads as improving money flow. A bearish divergence is the mirror image, with a higher high in price and a lower high in the MFI.

In a bullish failure swing, the MFI drops below 20 and climbs back above it. It then holds above 20 on the next pullback and breaks its prior high. The bearish swing runs the same way at 80. ChartSchool treats both kinds of signal as possible reversals when they come against the trend.

BTC closed early November at 77,433.9 USDT with an MFI of 28.1. ETH's MFI stood at 47.4, so both were above the oversold line.

Does the Money Flow Index Work in Crypto?

The oversold half of it did, on Phemex's crypto perpetuals from May 2024 to October 2026, and the overbought half barely did.

The test took 26 Phemex crypto perpetuals other than BTC and ETH and marked every fresh cross on their daily closes. A fresh cross under 20 is a close below the line after a close at or above it. It counted as right when the close ten days later was higher.

Crosses over 80 counted as right when the close ten days later was lower. All scored days on the same markets set the base rate.

That window leaned down. Only about 45% of all days were followed by a higher close ten days later. Oversold crosses did that about 59% of the time, a wide margin over the market's own drift. The median signal gained about 2.6% over those ten days, against a 1.5% fall for the median day.

The overbought line did less. Its crosses came before a lower close about 58% of the time against 55% for all days, a small edge in a market that was falling anyway.

The oversold lead held when the test looked five and 20 days ahead. The overbought edge was widest at five days, about 62% against 55%, and had gone by 20 days.

The rule failed hard on ETH. Its MFI crossed under 20 on 1 February 2026, and ten days later ETH had closed about 15% lower.

The test counted closes only. It didn't test the profit of any money flow index strategy, and it left out trading costs such as fees and funding.

Is the Money Flow Index a Leading Indicator?

ChartSchool says it can be. Its case rests on the idea that "volume leads price." ChartSchool calls RSI a momentum oscillator that "already leads prices" and says adding volume "can increase this lead time."

Read it as a claim to test. The MFI is built from the last 14 days of prices and volume, so any lead it has shows up as signals that come before a move. In the test above that happened on the oversold side and barely on the overbought side.

How Do You Trade the Money Flow Index?

The textbook use is as a second opinion. ChartSchool says it plainly, "As with all indicators, MFI should not be used by itself."

In practice, that means pairing a cross with something the price does. A failure swing or a divergence adds a second MFI signal. A break of the last swing high or low adds price's own vote.

The MFI gives no exit level of its own, so the exit comes from the chart and from how much you can afford to lose. Some traders set their stops with a trailing tool such as Wilder's Parabolic SAR indicator, which moves the stop as the price moves.

The test's numbers are counts of closes. A trade that was right ten days out could still have hit its stop on the way.

Money Flow Index vs RSI: Is MFI Better?

MFI wasn't clearly better than RSI on Phemex's crypto perpetuals, though it fired about half as often.

RSI uses 70 and 30 as its lines where the MFI uses 80 and 20. The same test ran both on the same markets and days.

The MFI's oversold result was about level with RSI's. Its overbought line was the slightly better warning, since RSI's overbought crosses came before a lower close less often than an ordinary day did. On BTC and ETH, RSI fired 47 times to the MFI's 19, so the MFI was the pickier of the two without being clearly sharper.

What Mistakes Do Traders Make With the Money Flow Index?

Selling Every Overbought Reading in a Strong Trend

ChartSchool's warning about strong trends showed up in Phemex's own BTC and ETH data. Ten fresh closes over 80 came before a lower close 20 days later only once, against 53% of all days, as prices kept climbing. Three of BTC's seven came within six days in April 2026, so read the ten as an example of the warning.

Trusting One Volume Feed

The MFI is only as good as the volume behind it. On an aggregate feed that sums volume across many venues, only 8 of the 19 BTC and ETH signals from Phemex's bars also fired there on the same day. ETH's MFI at the early-November close read 47.4 on Phemex's volume and about 33 on the aggregate feed. Read the MFI on the market you trade.

Using It Alone

Both mistakes above share a cause, a single reading treated as a trade. Pairing the MFI with price action helps, and placing stop-loss and take-profit orders before you enter caps what one wrong reading can cost.

How Can You Use the Money Flow Index on Phemex?

Phemex's futures chart carries the MFI as a built-in TradingView indicator. The steps below use the BTCUSDT perpetual, the market in the worked example.

Adding the MFI Indicator to a Phemex Chart

5. Open the BTCUSDT perpetual and pick the TradingView tab above the chart.

6. Choose D for daily bars, the timeframe the test used.

7. Open Indicators and type "Money Flow" into the search. Pick Money Flow Index, which the list shows above Chaikin Money Flow.

8. Check the legend, which reads MFI 14. Its Inputs tab holds one field, Length, set to 14. The pane draws dashed lines at 80 and 20.

Futures use leverage, and a leveraged position is closed automatically if losses reach its margin, the process behind liquidation in crypto trading.

Frequently Asked Questions

What is a good Money Flow Index setting?

Fourteen periods is the usual choice. ChartSchool calls it the default in SharpCharts and "the setting recommended by the creators." A shorter length makes the MFI more sensitive and a longer one less so. Phemex's chart opens it at 14.

What is the difference between the Money Flow Index and Chaikin Money Flow?

They're separate indicators that Phemex's chart lists one under the other. The MFI turns 14 days of volume-weighted price moves into a 0-to-100 reading. Chaikin Money Flow, which ChartSchool credits to Marc Chaikin, weights volume by where each close falls in its day's range and swings around zero.

Can the Money Flow Index go above 100?

No. The MFI is the share of positive money flow in the total, so it tops out at 100. It reaches that only when no day in the window had negative flow. BTC's daily MFI on Phemex peaked at 85.7 from February 2024 to early November 2026.

Bottom Line

Judge the Money Flow Index by what an ordinary day did on the same market. A higher close 59% of the time means little on its own. It stands out once you see that only 45% of all days managed the same in that window. The overbought record barely beat an ordinary day.

Measured that way, the 20 line earned a place on a crypto chart as a prompt to look closer at price. The 80 line was a weak warning that BTC's and ETH's strong runs went straight through.

Disclaimer: This article is for informational purposes only and is not financial advice. Cryptocurrency trading involves substantial risk. Always do your own research before making investment decisions.