This calculator helps you estimate the risk of your investment portfolio by calculating its variance. It’s useful for personal financial planning, assessing diversification, and making informed decisions about asset allocation.
Enter the weights and standard deviations for up to five assets to see your portfolio’s overall risk.
Portfolio Variance Calculator
Enter weights and standard deviations, then click Calculate.
How to Use This Tool
Enter the weight (as a percentage) and standard deviation (as a percentage) for each asset in your portfolio. The weights must total 100%. You can leave fields for unused assets at 0. The correlation coefficient is optional; if left blank, it defaults to 0 (no correlation between assets).
Click 'Calculate Variance' to see your portfolio's risk metrics. Use 'Reset' to clear all inputs.
Formula and Logic
Portfolio variance is calculated using the standard formula for a multi-asset portfolio: Variance = Σ(wi² * σi²) + ΣΣ(2 * wi * wj * σi * σj * ρij), where wi is the weight of asset i, σi is its standard deviation, and ρij is the correlation between assets i and j.
This tool assumes a constant correlation coefficient for all asset pairs for simplicity. In practice, correlations can vary, but this provides a reasonable estimate for personal financial planning.
Practical Notes
- For personal finance, consider how interest rates affect asset returns; higher rates may increase volatility for bonds.
- Compounding frequency isn't directly in this calculation, but it impacts overall returns—review your investment statements regularly.
- Tax implications: Variance helps assess risk, but remember that taxes on capital gains can affect net returns; consult a tax advisor for personalized advice.
- Budgeting habits: Use this tool monthly to track how diversification reduces risk in your savings or retirement accounts.
Why This Tool Is Useful
This calculator helps individuals and financial planners quickly estimate portfolio risk without complex software. It supports better decision-making for asset allocation, especially when balancing growth and safety in personal budgets or loan applications.
Frequently Asked Questions
What if my weights don't sum to 100%?
The tool will show an error message. Adjust your inputs so the total equals 100% for an accurate calculation.
Can I use this for retirement planning?
Yes, it's ideal for assessing risk in retirement portfolios. Combine it with other tools for a full financial picture.
How accurate is the correlation assumption?
It's a simplification. For precise planning, use historical correlation data from financial sources, but this tool gives a solid baseline.
Additional Guidance
For deeper analysis, pair this calculator with tools for expected return or Sharpe ratio. Always consider your risk tolerance and consult a financial advisor for major decisions.