What Is the Money Flow Index (MFI)? How to Read the Volume-Weighted RSI
The Money Flow Index, or MFI, is a momentum oscillator that bounds between 0 and 100 — and if that sounds like the RSI, you are halfway to understanding it. The key difference is in the name: MFI weights price movement by volume. Because of that, traders often call it the "volume-weighted RSI." It tries to answer a sharper question than price alone can: not just "is price rising or falling," but "is real money pushing it there?"
How the MFI is calculated
You rarely compute this by hand, but knowing the steps tells you what the line actually measures:
The volume term is what separates MFI from RSI. A move on heavy volume shifts the index far more than the same move on thin volume.
How to read it
A practical example
Say a market grinds to a new high but volume is fading, and MFI rolls over from 85 to 70 while price is still climbing. That gap — price up, money flow down — tells you the rally is running on fewer committed buyers. It is not a sell signal on its own, but it is a reason to tighten stops and stop adding to longs.
Strengths, limits and good habits
Because it includes volume, MFI can lead price at turning points slightly better than RSI in markets with reliable volume data — futures and equities especially. In spot forex, where centralized volume does not exist, brokers substitute tick volume, so treat the readings with more caution there.
The usual oscillator caveats apply: an overbought MFI can stay overbought for a long time in a strong trend, and divergence can persist far longer than your account can. Use MFI as confirmation within a plan — alongside structure, trend and your risk rules — not as a standalone trigger. Backtest the 14-period default against your own market and timeframe before you trust it live.
Educational content for discussion. Nothing here is investment advice — do your own testing and manage your risk.
The Money Flow Index, or MFI, is a momentum oscillator that bounds between 0 and 100 — and if that sounds like the RSI, you are halfway to understanding it. The key difference is in the name: MFI weights price movement by volume. Because of that, traders often call it the "volume-weighted RSI." It tries to answer a sharper question than price alone can: not just "is price rising or falling," but "is real money pushing it there?"
How the MFI is calculated
You rarely compute this by hand, but knowing the steps tells you what the line actually measures:
- Typical price for each period = (high + low + close) / 3.
- Raw money flow = typical price × volume for that period.
- Money flow is split into positive (days the typical price rose) and negative (days it fell).
- Money flow ratio = sum of positive money flow / sum of negative money flow over the lookback (default 14).
- MFI = 100 − (100 / (1 + money flow ratio)).
The volume term is what separates MFI from RSI. A move on heavy volume shifts the index far more than the same move on thin volume.
How to read it
- Overbought / oversold: readings above 80 are traditionally considered overbought, below 20 oversold. In strong trends, raise those thresholds (90/10) so you are not fighting the move.
- Divergence: this is where MFI earns its keep. If price makes a higher high but MFI makes a lower high, buying pressure is not confirming the new price — a classic warning of exhaustion. Bullish divergence is the mirror image at lows.
- Failure swings: MFI poking into extreme territory and then turning back without price confirming can flag a reversal before it shows up clearly on the chart.
A practical example
Say a market grinds to a new high but volume is fading, and MFI rolls over from 85 to 70 while price is still climbing. That gap — price up, money flow down — tells you the rally is running on fewer committed buyers. It is not a sell signal on its own, but it is a reason to tighten stops and stop adding to longs.
Strengths, limits and good habits
Because it includes volume, MFI can lead price at turning points slightly better than RSI in markets with reliable volume data — futures and equities especially. In spot forex, where centralized volume does not exist, brokers substitute tick volume, so treat the readings with more caution there.
The usual oscillator caveats apply: an overbought MFI can stay overbought for a long time in a strong trend, and divergence can persist far longer than your account can. Use MFI as confirmation within a plan — alongside structure, trend and your risk rules — not as a standalone trigger. Backtest the 14-period default against your own market and timeframe before you trust it live.
Educational content for discussion. Nothing here is investment advice — do your own testing and manage your risk.