What Is Money Flow Index (MFI)?
Money Flow Index (MFI) is a volume-weighted momentum indicator that oscillates on a 0–100 scale. It combines the overbought/oversold framework of RSI with the volume-weighting logic of money flow indicators.
Key levels:
- MFI > 80: Overbought—strong buying on high volume, reversal likely
- MFI < 20: Oversold—strong selling on high volume, bounce likely
- MFI = 50: Neutral midpoint
MFI answers the question: “Is there excessive buying or selling on high volume that suggests a reversal?” Unlike RSI, which ignores volume, MFI weights momentum by the volume behind it.
How MFI Works
Step 1: Calculate Typical Price Typical Price (TP) = (High + Low + Close) / 3
Step 2: Determine Money Flow Direction
- If TP today > TP yesterday: Up period, Money Flow = TP × Volume (positive)
- If TP today < TP yesterday: Down period, Money Flow = TP × Volume (negative)
Step 3: Sum Money Flows Over the Period
- Positive Money Flow (PMF) = Sum of money flow on up periods (typically 14)
- Negative Money Flow (NMF) = Sum of money flow on down periods (typically 14)
Step 4: Calculate Money Flow Ratio Money Flow Ratio = PMF / NMF
Step 5: Convert to 0–100 Scale MFI = 100 - (100 / (1 + Money Flow Ratio))
This formula ensures MFI oscillates between 0 and 100, with 50 as the midpoint.
Trading With MFI
Identify Overbought Conditions (Above 80)
When MFI exceeds 80, price has rallied with high volume, indicating strong buying. This overbought condition often precedes pullbacks.
Overbought setup:
- MFI above 80, price near recent high
- Look for rejection candle or resistance barrier
- Short the rejection, target the midline (MFI 50)
- Stop loss above the high
Example: EUR/USD rallies 200 pips, MFI reaches 85. A doji forms at resistance. Short the doji, with target at the moving average (where MFI would approach 50).
Identify Oversold Conditions (Below 20)
When MFI drops below 20, price has declined with high volume, indicating strong selling. This oversold condition often precedes bounces.
Oversold setup:
- MFI below 20, price near recent low
- Look for reversal candle or support bounce
- Buy the reversal, target the midline (MFI 50)
- Stop loss below the low
Example: GBP/USD declines 200 pips, MFI drops to 15. A hammer forms at support. Buy the hammer, with target at the moving average (where MFI would approach 50).
Spot Divergences
Divergences between price and MFI signal weakening momentum.
Bullish divergence: Price makes a new low, but MFI makes a higher low (less oversold). Selling pressure is fading; expect a bounce.
Bearish divergence: Price makes a new high, but MFI makes a lower high (less overbought). Buying pressure is fading; expect a pullback.
Use 50 as a Directional Signal
MFI above 50 shows more positive money flow (buying pressure). MFI below 50 shows more negative money flow (selling pressure). Use 50 as a trend filter.
- In uptrend, trade only when MFI > 50: Momentum is positive
- In downtrend, trade only when MFI < 50: Momentum is negative
Practical Trading Examples
Example 1: Overbought Short
- AUD/USD rallies 250 pips over 5 days
- MFI reaches 88 (deeply overbought)
- Price approaches resistance at 0.8800
- A bearish engulfing candle forms
- Short at the close of the engulfing candle
- Target the moving average or previous support
- Stop loss above the high
Example 2: Oversold Bounce
- USD/JPY declines 300 pips over 3 days
- MFI drops to 12 (deeply oversold)
- Price approaches support at 140.00
- A hammer candle forms on the support level
- Buy at the close of the hammer
- Target the moving average or previous resistance
- Stop loss below the low
Example 3: Divergence Warning
- EUR/GBP makes new high at 0.8620
- MFI only reaches 75, below its previous reading of 82 when price was at 0.8600
- Bearish divergence: the new high is weaker than the previous high
- Close long positions; prepare to reverse
- Expect pullback as MFI weakness signals fading momentum
MFI vs. RSI
Both measure momentum, but with different approaches:
| Feature | MFI | RSI |
|---|---|---|
| Calculation | Price weighted by volume | Price gains vs. losses |
| Volume weighting | Yes, volume is critical | No, volume ignored |
| Scale | 0–100 | 0–100 |
| Overbought | Above 80 | Above 70 |
| Oversold | Below 20 | Below 30 |
| Best for | Institutional flows | Pure momentum |
| Market type | Trending markets | All markets |
MFI is better for identifying when high-volume moves are unsustainable. RSI is better for pure momentum measurement.
MFI Period Selection
The period determines sensitivity:
- 7-period MFI: Very responsive, many signals, more noise
- 14-period MFI: Standard choice, good balance
- 21-period MFI: Less responsive, fewer signals, higher accuracy
Use shorter periods on higher timeframes. Use longer periods on lower timeframes to reduce false signals.
Combining MFI With Price Action
MFI is strongest when combined with:
- Support/Resistance: MFI extreme at a key level is more significant
- Candlestick patterns: MFI overbought/oversold + rejection/reversal candle = strong signal
- Trendlines: MFI extreme at a trendline add conviction
- Volume profile: Extreme MFI on unusual volume is more meaningful
Limitations of MFI
- Lagging indicator: MFI reflects past price and volume
- False signals in choppy markets: MFI oscillates between extremes without directional bias
- Overbought/oversold aren’t guarantees: Price can extend beyond these levels and continue
- Divergences need confirmation: Use price action to confirm divergence signals
Using MFI in Your Trading Journal
When you trade based on MFI, log:
- What MFI signal triggered the trade? (Overbought/oversold, divergence, 50-line cross)
- How extreme was the reading? (Extreme 85+ or 15-, moderate 75-79 or 21-25)
- What price action confirmed it? (Reversal candle, support/resistance, trendline)
- Did the trade profit? (Track which MFI setups are profitable)
Over time, refine which MFI-based setups work best for your strategy.
Key Takeaways
- MFI is volume-weighted momentum: Combines RSI logic with volume
- Overbought above 80, oversold below 20: These extremes signal reversals
- Use the 50 line as a trend filter: Above 50 is bullish, below is bearish
- Divergences warn of reversals: Price new extreme but MFI doesn’t = weakness
- Combine with price action: MFI works best with support, resistance, and candle patterns
Money Flow Index reveals whether buying or selling pressure is excessive on a volume basis. Use it to identify when moves are unsustainable and likely to reverse. MFI is most powerful when combined with confluence—key levels, price action, and other indicators.
