Money Flow Index

Install and import#

npm install fintech-algorithms

import { moneyFlowIndex } from "fintech-algorithms/technical-indicators/volume-indicators/money-flow-index";

Signature#

moneyFlowIndex(high, low, close, volume, p)

RSI computed on typical price weighted by volume — commonly described as volume-weighted RSI, and read on the same 0–100 scale.

Parameters#

Returns#

Record<string, (number | null)[]> · length same-as-input

Parallel series: typical_price, raw_money_flow, positive_flow, negative_flow, money_flow_ratio and mfi.

Warm-up#

The first p positions are null. One extra bar is needed beyond the window, because the first bar has no prior typical price to compare against.

Errors#

• When p < 1 or is not an integer — throws RangeError
• When the input series are not all the same length — throws RangeError

Complexity: time O(n), space O(n).

Worked example#

executed Captured by running this function on the input its own test provides. Real output of real code — but not asserted against a published figure.

Input#

[101.05, 101.52482, 102.098461, 102.729464, 103.36806, 103.963227]

Showing 6 of 120 elements.

[99.4, 99.462904, 99.936275, 100.512674, 101.151059, 101.802588]

Showing 6 of 120 elements.

[100.28, 100.686113, 101.200346, 101.789282, 102.408843, 103.010585]

Showing 6 of 120 elements.

[990000, 1066468.036, 1130033.236, 1170141.961, 1180511.26, 1160272.794]

Showing 6 of 120 elements.

Call#

moneyFlowIndex(high, low, close, volume, p)

Returns#

object with 6 fields: typical_price, raw_money_flow, positive_flow, negative_flow, money_flow_ratio, mfi

{
  "typical_price": [
    100.24333333333334,
    100.55794566666668,
    101.07836066666668,
    101.67714000000001,
    102.30932066666666,
    102.92546666666668
  ],
  "raw_money_flow": [
    99240900,
    107241834.81932473,
    114221906.99372847,
    118976687.98847154,
    120777305.0499507,
    119421618.78308721
  ],
  "positive_flow": [null, null, null, null, null, null],
  "negative_flow": [null, null, null, null, null, null],
  "money_flow_ratio": [null, null, null, null, null, null],
  "mfi": [null, null, null, null, null, null]
}

Other exports#

This module also exports obv, accumulationDistributionLine, chaikinMoneyFlow, volumePriceTrend, forceIndex. Every module additionally exports run as an alias of its primary function, and a meta object carrying its catalog id, domain, family, shape and article URL.

Diagrams#

Calculation flow#

flowchart LR
  A["Finalized finalized high, low, close, and nonnegative volume"] --> B["Validate order, alignment, and finite values"]
  B --> C["Typical price"]
  C --> D["Raw and directional flow"]
  D --> E["Positive / negative sums"]
  E --> F{"History and denominator valid?"}
  F -- "No · short history" --> G["warming-up + reason"]
  F -- "No · no finite scale" --> H["undefined + reason"]
  F -- "Yes" --> I["Money Flow Index"]
  I --> J["ready + aligned component trace"]

flowchart LR
    A["Same instrument and identifier?"] -->|Yes| B["Same venue or consolidated scope?"]
    A -->|No| X["Stop: different measurement"]
    B -->|Yes| C["Same volume unit and bar interval?"]
    B -->|No| X
    C -->|Yes| D["Same session and close policy?"]
    C -->|No| X
    D -->|Yes| E["Same corrections and price-volume adjustment basis?"]
    D -->|No| X
    E -->|Yes| F["Same MFI convention, seed, warm-up, and precision?"]
    E -->|No| X
    F -->|Yes| G["Compare intermediate components"]
    F -->|No| Y["Document convention difference"]
    G --> H["Compare final output"]

How it works#

This page states the contract — how to call it correctly. The article explains the concept: why it works, and where it breaks.

Read the article →

References#

• Money Flow (MFI) — TradingView
• Volume — TradingView
• TA-Lib function API and volume indicators — TA-Lib
• Consolidated Tape — U.S. Securities and Exchange Commission, Investor.gov
• Closing Price — U.S. Securities and Exchange Commission, Investor.gov
• What is Volume? — CME Group
• TA-Lib momentum indicator functions — TA-Lib
• Claim-role ledger
• Evidence boundary
• Enhanced claim-to-source map
• Public evidence boundary

The rest of the Volume Indicators family#

• On-Balance Volume (OBV)On-balance volume: a running total that adds the bar's volume when price closed up and subtracts it when price closed down.
• Accumulation/Distribution LineWeights each bar's volume by where the close sat within that bar's range, then accumulates.
• Chaikin Money FlowMoney-flow volume summed over a lookback and divided by total volume over the same window — the accumulation/distribution idea …
• Volume Price TrendLike OBV, but each bar contributes volume scaled by the size of the return rather than only its sign — so a 3% move counts for …
• Force IndexPrice change multiplied by volume, then smoothed.
• Chaikin A/D OscillatorBuilds the cumulative accumulation/distribution line from the money flow multiplier and volume, then returns the difference bet…
• Session VWAP IndicatorAccumulates typical price times volume divided by cumulative volume, restarting the accumulation at every new session.
• Anchored VWAPAccumulates typical price times volume divided by cumulative volume from a chosen anchor bar onward, with no session reset.
• Negative Volume IndexTracks a cumulative index seeded at 1000 that compounds the close-to-close return only on bars whose volume fell against the pr…
• Positive Volume IndexTracks a cumulative index seeded at 1000 that compounds the close-to-close return only on bars whose volume rose against the pr…
• Ease of MovementDivides the typical-price change by a box ratio built from scaled volume over the bar range, then smooths that raw reading with…
• Klinger Volume OscillatorSigns each bar's volume force by the direction of the high-low-close sum and weights it by where the close sits in the bar rang…
• Volume OscillatorReturns the difference between a fast and a slow simple moving average of raw volume.
• Percentage Volume OscillatorExpresses the gap between a fast and a slow EMA of volume as a percentage of the slow EMA.
• Volume Rate of ChangeMeasures the percentage change in volume against the bar period positions earlier.
• Relative VolumeDivides each bar's volume by the simple moving average of volume over the preceding window, giving a multiple of normal activity.
• Money Flow Multiplier and Money Flow VolumeReturns the per-bar money flow multiplier, the close's position within the bar range mapped to minus one through one, and that …
• Volume-Weighted MACDRuns the MACD construction on volume-weighted moving averages of close instead of exponential ones, and smooths the resulting l…
• Volume Zone OscillatorSigns each bar's volume by the direction of the close change, then expresses the EMA of that signed volume as a percentage of t…
• Twiggs Money FlowAccumulates volume weighted by where the close sits inside a range extended to include the prior close, then divides the EMA of…