--- title: "Market Facilitation Index: Formula" description: "The Market Facilitation Index (Bill Williams) is the bar's price range divided by its volume: how much price moved per unit of volume. Williams reads it..." canonical: https://www.getswoopr.com/indicators/volume/market-facilitation-index/ source: "Swoopr Investment: https://www.getswoopr.com" --- ## Direct Answer > The Market Facilitation Index (Bill Williams) is the bar's price range divided by its volume: how much price moved per unit of volume. Williams reads it together with the change in volume. A higher value means price moved a lot for each unit of volume, and a lower value means it needed more volume to travel. # Market Facilitation Index: Formula, Meaning, Signals, Examples and How to Use It ## How Is Market Facilitation Index Calculated? The Market Facilitation Index (Bill Williams) is the bar's price range divided by its volume: how much price moved per unit of volume. Williams reads it together with the change in volume. **Formula:** `MFI = (High - Low) / Volume` **Inputs:** - Bar high and low - Bar volume - Comparison with the prior bar's MFI and volume **Worked example.** A bar with a range of 101.50 to 102.50 on a volume of 500 contracts has a Market Facilitation Index of 0.002000. The inputs are illustrative numbers, not market data. **Reading it.** A higher value means price moved a lot for each unit of volume, and a lower value means it needed more volume to travel. Williams classifies bars by whether MFI and volume each rose or fell versus the prior bar, giving four bar types that he names green, fade, fake and squat. **Limits.** The bar-type names and their meanings are Williams' own framework rather than a general market law. Values depend on the volume unit and bar size, and in markets reporting tick volume the denominator is only a proxy for traded size. ## What is Market Facilitation Index? The Market Facilitation Index (Bill Williams) is the bar's price range divided by its volume: how much price moved per unit of volume. Williams reads it together with the change in volume. ## How to use Market Facilitation Index A higher value means price moved a lot for each unit of volume, and a lower value means it needed more volume to travel. Williams classifies bars by whether MFI and volume each rose or fell versus the prior bar, giving four bar types that he names green, fade, fake and squat. A reading alone is never a buy or sell signal; it needs context from price structure, volume, volatility and the broader market regime. ## Strengths - Dividing range by volume expresses how much price moved per unit traded, so a bar can be described as easy or hard in price terms. - The two-variable ratio makes the figure usable together with volume change, which is how Williams classifies bars. - Reproducible when the formula and data convention are fixed. ## Weaknesses and limitations - Low-volume bars with an ordinary range yield large values, so the series is skewed upward by quiet bars. - The value is in price per unit of volume, so it rises with price level and cannot be compared between instruments directly. - Correlated indicators can create false confidence by repeating the same underlying information. ## Editorial and risk note This page is educational content, not individualized investment advice. It should not imply guaranteed prediction, accuracy or outperformance. ## Frequently Asked Questions Is Market Facilitation Index a buy or sell signal? No. A higher value means price moved a lot for each unit of volume, and a lower value means it needed more volume to travel. The bar-type names and their meanings are Williams' own framework rather than a general market law. A trade built on it still needs a trigger, an invalidation rule, a position size and realistic execution assumptions. What is the best setting for Market Facilitation Index? Market Facilitation Index takes these inputs: bar high and low; bar volume; comparison with the prior bar's MFI and volume. There is no universal best setting for the tunable ones, so test them across instruments, regimes and out-of-sample periods and favor stable parameter regions over one historical winner. Can Market Facilitation Index be used by itself? The bar-type names and their meanings are Williams' own framework rather than a general market law. Values depend on the volume unit and bar size, and in markets reporting tick volume the denominator is only a proxy for traded size. For that reason it is read next to measures of direction, participation, valuation, liquidity and risk, not alone. Does Market Facilitation Index work on every timeframe? The calculation (MFI = (High - Low) / Volume) can be run on any bar size, but behavior is not portable: a reading on a five-minute chart describes a very different market window from the same reading on a daily chart. Validate the exact timeframe before relying on it. Why does Market Facilitation Index give false signals? Low-volume bars with an ordinary range yield large values, so the series is skewed upward by quiet bars. The value is in price per unit of volume, so it rises with price level and cannot be compared between instruments directly. Lag, noise and regime changes add to this, because market participants react to new information after the reading is calculated. How should Market Facilitation Index be backtested? Rebuild Market Facilitation Index from bar high and low using point-in-time data, write the rules before testing, include delisted securities where relevant, model realistic fills and costs, reserve a validation sample and compare with a simpler baseline. S Swoopr Editorial Team The Swoopr Editorial Team produces independent investment education, research, and tools for understanding markets, evaluating opportunities, and managing risk. All content is educational only and does not constitute personalized investment advice. See our [editorial policy](https://www.getswoopr.com/legal/editorial-policy/) and [corrections policy](https://www.getswoopr.com/legal/corrections-policy/).