What Money Flow Index (MFI) measures
Raw money flow multiplies typical price by volume. Flow is classified as positive or negative according to the change in typical price, and the ratio of recent positive to negative flow is mapped onto a zero-to-100 scale.
Volume therefore affects the oscillator directly: a high-volume bar contributes more flow than a quiet bar with a similar price.
How to read Money Flow Index (MFI)
Read the 20 and 80 levels as contextual zones rather than forced reversal points. Sustained directional movement can keep MFI elevated or depressed.
Compare price swings with MFI swings to study whether volume-weighted momentum confirms or diverges from price. A divergence is a prompt for closer inspection, not proof of reversal.
AptiStockX default settings
AptiStockX displays MFI curves at 14, 20, and 30 periods with reference levels at 20 and 80, matching the desktop defaults.
The interactive example starts with only Money Flow Index (MFI) enabled. It intentionally uses AptiStockX's synthetic SPY demo data, so the page teaches the charting workflow without presenting live market information.
A practical AptiStockX workflow
Use the 14-period curve for faster response and 20/30 for smoother context. Inspect cases where the fast line reaches an extreme but the slower lines do not.
Compare MFI with RSI on separate tutorial pages. Similar price momentum with different volume participation can cause the two oscillators to tell different stories.
Limitations and interpretation
MFI inherits every limitation of the source volume data. Venue coverage, asset type, missing volume, and provider corrections can affect the result.
The classification of flow is a formula, not direct knowledge of buying and selling intent. Every completed trade includes both a buyer and a seller.
Technical indicators summarize historical data. They do not predict outcomes, provide personalized investment advice, or replace independent research and risk management.
AptiStockX is a native desktop stock charting and analysis application for self-directed traders and researchers who want local data, native speed, and a durable workflow.