Short answer: the money flow index is a volume-weighted momentum indicator that runs from 0 to 100. It multiplies each bar's typical price by its trading volume, then sorts that money flow into up bars and down bars over 14 periods. The ratio becomes an oscillator. Readings above 80 flag overbought conditions and readings below 20 flag oversold ones. Because volume sits inside the maths, MFI reacts to heavy participation in a way that a price-only oscillator cannot.
This page is for forex, index, metals and crypto CFD traders who have this trading indicator on their chart and want a plain reading rule.
How the money flow index is calculated
Four steps, repeated every bar:
- Typical price: high plus low plus close, divided by three.
- Raw money flow: typical price multiplied by the bar's volume.
- Sort it: positive if the typical price rose against the previous bar, negative if it fell.
- Ratio and index: total positive flow divided by total negative flow. MFI equals 100 minus 100 divided by (1 plus that ratio).
The standard lookback is 14 bars. To keep the arithmetic tidy, here is a four-bar window on a BTC CFD with round numbers. Bar 0 only supplies the starting typical price.
| Bar | High | Low | Close | Typical price | Volume | Money flow |
|---|---|---|---|---|---|---|
| 0 | 60,300 | 59,700 | 60,000 | 60,000 | 1,000 | baseline |
| 1 | 60,900 | 60,000 | 60,600 | 60,500 | 1,200 | +72.6m |
| 2 | 61,200 | 60,300 | 60,900 | 60,800 | 800 | +48.6m |
| 3 | 61,000 | 60,100 | 60,400 | 60,500 | 1,500 | -90.8m |
| 4 | 60,800 | 59,900 | 60,200 | 60,300 | 900 | -54.3m |
Positive flow totals 121.2m and negative flow 145.0m. The ratio is roughly 0.84 and MFI prints about 45.5. Price closed the window 200 points higher than it started, yet the index sits below 50. The two down bars carried heavier volume, and MFI is honest about that.
Reading MFI levels: overbought, oversold and divergence
The fixed scale is the main attractiveness of the tool in technical analysis. Three readings matter.
- Above 80: overbought. During a strong trend the reading can stubbornly hold there for a dozen bars, so treat it as a warning to stop adding, seldom a reason to sell.
- Below 20: oversold, the same logic in reverse. Some traders wait for 90 and 10 on crypto CFDs, which move violently enough to hit 80 and 20 on ordinary days.
- The 50 line: money flow is balanced. A cross of 50 with the higher-timeframe trend is a humble but useful confirmation.
Divergence is the more consequential reading. Price makes a higher high while MFI prints a lower high, so fewer contracts paid up for the new extreme. The reverse hints that sellers are running out of participation.
A case that repeats around scheduled news. An index CFD grinds higher for two weeks with MFI near 70. A jobs release lands, price spikes to a fresh high, and the next bars carry the heaviest volume of the month with falling typical prices. All of it lands in the negative bucket, so MFI drops sharply while price action still looks fine. Traders who read the drop halved size before the reversal.
MFI versus RSI, OBV and the A/D line
MFI is often called volume-weighted RSI, and that is roughly right. The RSI indicator uses close-to-close price change only. MFI uses typical price multiplied by volume, so a quiet bar scarcely moves it and a crowded bar moves it a lot.
| Tool | Input | Scale | Weak spot |
|---|---|---|---|
| Money flow index | Typical price times volume | 0 to 100 | Lumpy on thin tick volume |
| RSI | Close-to-close change | 0 to 100 | Blind to participation |
| On balance volume | Whole-bar volume, sign from the close | Unbounded | No fixed overbought level |
| Accumulation/distribution | Volume weighted by close within the range | Unbounded | Ignores gaps between bars |
The two unbounded lines are cumulative. On balance volume and the accumulation distribution indicator only make sense by slope and by divergence against price. MFI can also be read by level, the more forgiving choice for a trader who wants a fixed threshold. The trade-off is that a bounded oscillator turns jittery at short lookbacks.
A decision framework for when MFI earns a place on the chart
MFI is a filter inside trading strategies, rarely a strategy on its own. A common approach:
- Use MFI when volume data means something: index and crypto CFDs in liquid sessions. A thin overnight session on a minor pair mostly produces patchy noise.
- Use MFI for divergence at a level you already marked from structure.
- Use RSI instead when your feed's tick volume looks stale or differs sharply from another broker's.
- Stand aside when MFI has sat above 80 for ten or more bars. Fading that is a thankless job.
Worked sizing example. A 10,000 account risks 1 percent per trade, or 100. A bearish divergence on EUR/USD appears at resistance with a 50-pip stop, so the position is 0.2 standard lots. If MFI merely crossed under 80 without a divergence, halve that size or skip the trade. Every extra entry pays spread and commission cost, and a filter that fires on every 80 cross will squander an edge on charges.
Common mistakes and limitations of MFI
There is no central tape for spot forex or most CFDs, so the formula runs on tick volume from one provider. A divergence visible on one platform may be absent on the next. Beyond that, the mistakes that cost traders most:
- Selling the first cross above 80. In a fresh trend the index can print 85 for days while price climbs, and shorting that is precarious.
- Reading MFI on a 1-minute chart. The window covers 14 minutes, the line turns skittish, and every scheduled release swamps it.
- Ignoring gaps. A bar that gaps up 200 points and closes weak still counts as positive flow, because its typical price sits above the previous one. Lopsided, but that is the maths.
- Treating divergence as an entry. It is a reason to decelerate: tighten the stop, halve size, stop adding.
Bluntly, MFI is weakest in disorderly markets, exactly when a nervous trader wants a number to lean on. Results vary, and the tool earns its keep on calm, liquid instruments where market trends are already visible.
Fitting MFI to prop-firm evaluation limits
Three counter-trend shorts on one overbought reading can exhaust a daily loss limit before lunch. A static total drawdown makes a string of small divergence trades precarious. So the sensible use is subtractive: let MFI remove trades rather than add them.
Pivex runs a one-step evaluation with no time limit and no minimum number of trading days. Nothing pushes you to force an entry when MFI drifts around 50. The daily loss limit resets each day and the total drawdown is static rather than trailing. That rewards a trader who waits for divergence at a marked level and quietly skips the rest. The built-in assistant tracks your limits, so attention stays on the chart.
Next step: add MFI under one instrument you already trade and compute it by hand for a few bars, so the money flow stops feeling abstract. Mark every divergence at your levels for 20 sessions. If the record earns your trust, bring it into a Pivex evaluation, where the assistant watches your drawdown while you watch the index.
Related guides: the RSI indicator and on balance volume.
Before participating, review Pivex's current program rules and decide whether a simulated proprietary trading evaluation fits your experience and risk limits. Participation does not guarantee a reward, income, or any particular trading result.