What the Portfolio Standard Deviation Calculator is for
Estimate two-asset portfolio volatility from one weight, both volatilities, and correlation.
It makes the prices, cash flows, rates, time periods, weights, and model conventions explicit so you can inspect an entered scenario without hidden live-market assumptions.
Calculation structure
Follow the stated model and units
σp = √[w²σ1² + (1−w)²σ2² + 2w(1−w)ρσ1σ2].
Visual explanation
See how the inputs become the result
Assets and weightsReturn contribution
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Volatility and dependenceRisk estimate
σp = √[w²σ1² + (1−w)²σ2² + 2w(1−w)ρσ1σ2].
Read the estimate correctly
Use the result within its boundaries
A 50/50 portfolio of 10% and 20% volatility assets with zero correlation has volatility about 11.18%.
This is a two-asset single-period covariance scenario. Volatility and correlation are assumed stable.
Quick guide
How to use this calculator
Enter the cash flows, values, rates, timing, or portfolio assumptions named in the fields.
Use one consistent period and currency convention throughout the scenario.
Read the calculator-specific model limits before interpreting the result.
Calculation method
Calculation method
σp = √[w²σ1² + (1−w)²σ2² + 2w(1−w)ρσ1σ2].
Model, simulation, root, square-root, and compounding outputs are estimates and are visibly marked approximate.
Worked example
Worked example
A 50/50 portfolio of 10% and 20% volatility assets with zero correlation has volatility about 11.18%.
σp = √[w²σ1² + (1−w)²σ2² + 2w(1−w)ρσ1σ2].
Supported inputs
Precision and limits
Visible input limits
Inputs support up to 12 decimal places and lists support at most 1,200 rows. Iteration and simulation bounds are displayed in their fields.
International scope
No exchange, tax system, reporting standard, currency, fund rule, trading calendar, or market convention is selected automatically.
Decision boundary
Outputs are entered scenarios, not valuations, forecasts, risk limits, executable trades, suitability decisions, or recommendations.
Calculator-specific assumptions
This is a two-asset single-period covariance scenario. Volatility and correlation are assumed stable.
