Quick guide
How to use this calculator
- Enter the contract, market, expiry, rate, and position assumptions named by the fields.
- Keep premiums, prices, multipliers, contract counts, and time conventions consistent.
- Read the exact expiry-payoff or model assumptions before interpreting the result.
Calculation method
Calculation method
Vega = Se^(−qT)φ(d1)√T ÷ 100.
Expiry-payoff arithmetic uses the entered terminal underlying price. Model-derived values are explicitly estimates and reject unsupported domains.
Worked example
Worked example
The result estimates value change for a one percentage-point volatility move.
Vega = Se^(−qT)φ(d1)√T ÷ 100.
Supported inputs
Precision and limits
Visible input limits
Fixed decimals accept up to 30 digits and 12 decimal places with absolute values capped at 1e12. General rates are bounded from −100% through 1000% where signed rates are meaningful.
No contract or market feed
No exchange specification, live quote, exercise style, dividend schedule, settlement rule, margin model, or contract multiplier is selected automatically.
Decision boundary
Outputs are entered scenarios, not quotes, forecasts, arbitrage findings, risk limits, suitability judgments, or recommendations.
Calculator-specific assumptions
Call and put vega are equal under the stated European model.