--- title: "Ulcer Index: Formula, Meaning & Signals" description: "The Ulcer Index, developed by Peter Martin, measures downside risk as the root mean square of percentage drawdowns from the running highest close over a..." canonical: https://www.getswoopr.com/indicators/volatility/ulcer-index/ source: "Swoopr Investment: https://www.getswoopr.com" --- ## Direct Answer > Ulcer Index is a volatility measure used to measure dispersion, range, implied uncertainty, or expansion/contraction in price movement. The production page must define the exact calculation convention before interpreting higher or lower readings, because platform and provider implementations can differ. # Ulcer Index: Formula, Meaning, Signals, Examples and How to Use It ## How Is Ulcer Index Calculated? The Ulcer Index, developed by Peter Martin, measures downside risk as the root mean square of percentage drawdowns from the running highest close over a lookback. It captures both depth and duration of declines. **Formula:** `R_i = 100 x (Close_i - max Close over the period) / max Close over the period; Ulcer Index = sqrt( sum of R_i^2 / n )` **Inputs:** - Closing prices - Lookback period n (commonly 14) - Highest close in the lookback **Worked example.** Percentage drawdowns of -2, -4 and 0 from the running high give an Ulcer Index of 2.58. The inputs are illustrative numbers, not market data. **Reading it.** A higher value means deeper or longer drawdowns from recent highs. Because squaring weights deep declines heavily and only declines count, a steadily rising price scores close to zero. **Limits.** It measures only drawdown from highs, not the upside, so it describes pain rather than total variability. The lookback matters, and it depends on the starting point of the window. ## Indicator overview | Attribute | Value | | --- | --- | | Category | Volatility | | Asset classes | Stocks, ETFs, Indexes, Options, Futures, Forex, Crypto, Commodities | | Output type | Ratio/index/scalar | | Parameters | Varies by implementation; document exact settings on use | ## What is Ulcer Index? Ulcer Index is a volatility measure used to measure dispersion, range, implied uncertainty, or expansion/contraction in price movement. The production page must define the exact calculation convention before interpreting higher or lower readings, because platform and provider implementations can differ. For Swoopr, the canonical profile separates definition, calculation, interpretation and decision use. That keeps readers from collapsing a descriptive metric into a trading strategy. An indicator can describe trend, momentum, volatility, participation, positioning or risk without providing a complete entry, exit, sizing or portfolio decision. ## What does it measure? Ulcer Index measures specific market properties in the Volatility domain. The practical value is repeatability: the same inputs and formula can be applied across a defined dataset, allowing users to compare readings through time or across instruments when the calculation convention is held constant. ## How to read Ulcer Index Interpretation depends on the market property being measured. A descriptive reading is not automatically predictive. The same numerical state can lead to different outcomes in a strong trend, quiet range, event-driven gap or illiquid market. Always combine with context from price structure, volume, and broader market regime before drawing conclusions. ## Strengths - Squaring percentage drawdowns weights deep declines more than shallow ones, and including every bar captures how long a decline lasted. - It uses only closes and a running maximum, so it can be rebuilt from a price series with no return statistics. - Reproducible when the formula and data convention are fixed. ## Weaknesses and limitations - The running high is taken within the lookback, so a high just outside the window is ignored and drawdown can look smaller than from the longer peak. - Because drawdowns are squared and averaged, a long mild decline and a short sharp one can produce similar values. - Correlated indicators can create false confidence by repeating the same underlying information. ## Choose your next step ### Apply - [Ulcer Index Explained](https://www.getswoopr.com/learn/technical-analysis/indicators/ulcer-index/) Step-by-step use, worked examples and the mistakes to avoid ## Related Swoopr content - Related guide: [Ulcer Index Explained](https://www.getswoopr.com/learn/technical-analysis/indicators/ulcer-index/) ## Editorial and risk note This page is educational content, not individualized investment advice. It should not imply guaranteed prediction, accuracy or outperformance. Where multiple valid definitions exist, Swoopr states the alternatives and the reason for selecting its primary convention. ## Frequently Asked Questions Is Ulcer Index a buy or sell signal? No. A higher value means deeper or longer drawdowns from recent highs. It measures only drawdown from highs, not the upside, so it describes pain rather than total variability. 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 Ulcer Index? Ulcer Index takes these inputs: closing prices; lookback period n (commonly 14); highest close in the lookback. 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 Ulcer Index be used by itself? It measures only drawdown from highs, not the upside, so it describes pain rather than total variability. The lookback matters, and it depends on the starting point of the window. For that reason it is read next to measures of direction, participation, valuation, liquidity and risk, not alone. Does Ulcer Index work on every timeframe? The calculation (R_i = 100 x (Close_i - max Close over the period) / max Close over the period; Ulcer Index = sqrt( sum of R_i^2 / n )) 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 Ulcer Index give false signals? The running high is taken within the lookback, so a high just outside the window is ignored and drawdown can look smaller than from the longer peak. Because drawdowns are squared and averaged, a long mild decline and a short sharp one can produce similar values. Lag, noise and regime changes add to this, because market participants react to new information after the reading is calculated. How should Ulcer Index be backtested? Rebuild Ulcer Index from closing prices 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. ## References - [Peter Martin: Ulcer Index and UPI Measure Investment Risk and Risk-Adjusted Performance](https://www.tangotools.com/ui/ui.htm) 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/).