What is portfolio volatility?

Portfolio volatility is the annualized standard deviation of a portfolio's returns. It measures how much the portfolio's value fluctuates around its average return over time. Higher volatility means wider swings in value — both gains and losses. For a diversified portfolio, volatility depends not just on individual asset volatilities but also on the correlations between them. Our tool calculates annualized volatility from return or price series and computes weighted portfolio volatility from the full covariance matrix.

What is Value at Risk (VaR)?

Value at Risk (VaR) is the maximum expected loss over a given time horizon at a specified confidence level. For example, a 1-day 95% VaR of $5,000 means there is a 5% probability of losing more than $5,000 in a single day. Our calculator uses the parametric method: VaR = Portfolio Value × Daily Volatility × Z-Score × sqrt(Holding Period), where the Z-score is 1.645 at 95% confidence. CVaR (Conditional VaR) shows the expected loss when VaR is exceeded.

What is a good Sharpe ratio?

Sharpe ratio = (Portfolio Return - Risk-Free Rate) / Portfolio Volatility. A Sharpe ratio above 1.0 is generally considered good, above 1.5 is very good, and above 2.0 is excellent. Below 0.5 suggests poor risk-adjusted returns, and a negative Sharpe ratio means the portfolio is underperforming the risk-free rate on a risk-adjusted basis. The Sortino ratio is a variant that only penalizes downside volatility, making it more appropriate for portfolios with positively skewed returns.

How does diversification reduce portfolio volatility?

When two assets have a correlation below 1.0, combining them in a portfolio produces volatility lower than the weighted average of their individual volatilities. The lower the correlation, the greater the reduction. Portfolio volatility = sqrt(sum of w_i * w_j * sigma_i * sigma_j * rho_ij across all pairs), where rho is the correlation coefficient. A portfolio of assets with zero correlation reduces volatility by roughly the square root of the number of assets compared to holding a single asset.

Is this portfolio volatility calculator free?

Yes. The Portfolio Volatility Calculator Pro on StockToolHub is completely free with no registration, account, or subscription required. All five tabs — Volatility, Portfolio Risk, Correlation, Sharpe & Sortino, and Stress Test — are fully accessible.

Portfolio Volatility Calculator Pro — Volatility, VaR, Correlation, Sharpe & Stress Test

Asset Details

Asset / Ticker optional

Period

Trading Periods/yr

days

252 daily · 52 weekly · 12 monthly

Enter Periodic Returns (%)

Returns (comma-separated)

Enter percentage returns separated by commas. Minimum 3 periods required.

Or Enter From Prices

Prices (comma-separated)

Auto-calculates log returns from price series.

Annualized Volatility

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Enter returns or prices to calculate

Periodic Std Dev

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Mean Return (periodic)

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Annualized Return

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Observations (N)

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Min Return

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Max Return

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Volatility Level

Low <10% Moderate High >30%

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Return Distribution — Frequency Histogram

Portfolio Value & Risk Parameters

Portfolio Value

Annualized Portfolio Volatility

From Volatility tab or enter manually

Expected Annual Return

Time Horizon

days

1 = one-day VaR, 252 = one-year VaR

Confidence Levels

VaR Confidence Levels

90% 95% 99%

Value at Risk (95%, 1-day)

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Enter portfolio value and volatility

Confidence	Z-Score	VaR ($)	VaR (%)	CVaR ($)	CVaR (%)

Daily Volatility

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Expected Annual Gain

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1σ Range (1yr)

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2σ Range (1yr)

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Return Distribution & VaR Thresholds

Asset / Ticker	Weight (%)	Ann. Volatility (%)

Weighted Portfolio Volatility

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Enter assets, weights and correlations

Weighted Avg Volatility

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Diversification Benefit

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Weight Check

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Assets

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Volatility Contribution by Asset

What each tab calculates

Volatility

Calculates annualized volatility and standard deviation from a user-entered series of periodic returns or a price series (auto-converts to log returns). Shows mean return, annualized return, min and max, observation count, a volatility level gauge, and a return frequency histogram.

Portfolio Risk

Calculates Value at Risk (VaR) and Conditional VaR (CVaR/Expected Shortfall) at 90%, 95% and 99% confidence levels for any holding period. Shows daily volatility, expected gain, 1σ and 2σ annual ranges, and a normal distribution chart with VaR threshold markers.

Correlation

Computes weighted portfolio volatility from individual asset weights, volatilities and pairwise correlation coefficients using the full covariance matrix formula. Shows diversification benefit versus weighted average volatility and volatility contribution by asset.

Sharpe & Sortino

Calculates Sharpe ratio (excess return / total volatility), Sortino ratio (excess return / downside volatility), Information ratio (active return / tracking error), and Calmar ratio. Compares all metrics against a benchmark portfolio with a grouped bar chart.

Stress Test

Applies seven historical crisis scenarios (2008 GFC, 2020 COVID crash, 2000 dot-com, 1987 Black Monday, 2022 bear market, 2011 correction and 1973 oil crisis) to the portfolio, scaled to equity and bond allocation. Shows loss in dollars and recovery time estimate for each scenario.