Atrsize

Atrsize is a term used in some financial trading software to refer to a size parameter associated with the Average True Range (ATR) volatility measure. It is not a universally standardized term, and its precise meaning can vary by platform, but it is commonly defined as a multiplier of the ATR over a specified lookback period, used to determine risk management settings such as stop-loss distance or position sizing.

In typical usage, atrsize is calculated as atrsize = k × ATR(n), where n is the lookback period for the ATR and k is a user-defined multiplier. For example, with ATR(14) and a multiplier of 2, atrsize doubles the average range of price movement over the past fourteen periods. This approach adapts risk and exit spacing to current market volatility: higher ATR values yield larger stop distances and potentially larger position sizes, while lower ATR values produce tighter stops and smaller positions.

The concept is intended to help traders manage risk relative to market volatility, rather than using fixed dollar or pip amounts. It supports volatility-based position sizing and dynamic stop placement, aiming to maintain a consistent risk profile across varying market conditions.

Because atrsize is not governed by a single standard, readers should verify its exact definition in the specific trading platform, script, or documentation where it appears. Related concepts include the ATR itself, volatility targeting, and risk-based stop strategies.

See also: Average True Range, volatility-based risk management, position sizing.