volatility

Volatility measures the rate and magnitude of price fluctuations in a financial instrument over a specific period. It quantifies the dispersion of returns around the mean, indicating how much an asset’s price deviates from its average. In forex trading, volatility determines risk exposure and potential profit or loss; higher volatility means wider price swings and greater uncertainty. This concept applies to all timeframes and currency pairs but is most relevant for short-term trading strategies and risk management.

Realised Volatility = stdev(returns) × sqrt(periods per year)

Where:

• stdev(returns) = standard deviation of daily logarithmic returns
• periods per year = number of trading periods (e.g., 252 for daily data)

Assume the AUD/USD pair has daily returns over 20 trading days with a standard deviation of 0.005 (0.5%). Using 252 trading days per year: Realised Volatility = 0.005 × √252 ≈ 0.005 × 15.87 = 0.0794 (7.94%). This means the annualised price variability of AUD/USD is approximately 7.94%, indicating a moderate level of risk.

• JPY pairs: Volatility calculations for pairs involving the Japanese yen (e.g., USD/JPY) often use pip-based standard deviation due to different decimal conventions, which can skew comparisons with non-JPY pairs.
• ASIC regulation: Australian traders under ASIC must account for volatility in leverage limits; higher-volatility pairs may trigger margin calls sooner, as brokers adjust requirements based on realised volatility.
• Non-standard periods: For weekly data, use 52 periods per year; for monthly, use 12. Using an incorrect period count distorts annualised volatility figures.

• ATR
• Implied volatility
• Standard deviation
• Risk management