What Is Historical Volatility?
Historical volatility measures how much an asset’s price has varied over a specific period, based on past price movements. It is usually calculated as the standard deviation of returns and expressed as a percentage. A higher reading indicates that price has fluctuated more sharply, while a lower reading reflects steadier movement. It tells traders how turbulent an instrument has been, not how it will behave next.
How Historical Volatility Is Measured
Historical volatility is derived from past price data over a chosen window, such as 20 or 30 days. The returns over that period are used to calculate a standard deviation, which is then often annualised for comparison. Because it looks only at what has already happened, it is sometimes called realised volatility.
Historical Versus Implied Volatility
| Feature |
Historical Volatility |
Implied Volatility |
| Direction |
Backward-looking |
Forward-looking |
| Source |
Past price movements |
Option prices |
| Measures |
What price has done |
Expected future movement |
Why It Matters
Traders use historical volatility to size positions, set stop distances, and understand how an instrument typically moves. Comparing historical with implied volatility can also highlight whether the market expects calmer or more turbulent conditions ahead than the recent past suggests.
Reading Volatility With Care
Historical volatility describes the past and offers no promise about the future. A quiet period can give way to sudden, sharp moves, and a single calculation window can paint an incomplete picture. Using volatility as one input among several, rather than a precise forecast, helps traders avoid over-relying on a backward-looking measure.
Putting Volatility in Context
Historical volatility helps traders gauge how restless or calm an instrument has been, which supports decisions on risk and position size. When read alongside implied volatility and current conditions, it becomes a useful part of a balanced analysis. VT Markets traders can study volatility across forex, indices, and commodities to inform their approach.
Risk Warning: Trading CFDs involves significant risk and may not be suitable for all investors. Losses can exceed your initial deposit. Please ensure you fully understand the risks involved before trading.
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