WACC Calculator guide
WACC combines the required returns of capital providers using market-value weights. It is commonly used to discount operating cash flow with comparable risk.
The preserved calculator includes CAPM, preferred stock, scenarios, optimal structure, trends, benchmarks, history, and exports.
How to use the WACC calculator
- Enter current amounts: Use current, documented values from the same relevant period.
- Enter assumptions: Use realistic rates, percentages, periods, and costs where applicable.
- Review the full result: Review the primary estimate together with its supporting measures.
- Stress-test risk: Model less favorable timing, value, cost, or rate assumptions.
Formula and variables
The estimate applies the entered values and assumptions to the stated formula.
WACC = equity weight × cost of equity + debt weight × cost of debt × (1 − tax rate)- Inputs — Entered values
- The amounts, percentages, or periods supplied to the calculator.
- Result — Calculated output
- The estimate produced by applying the formula to the entered values.
Worked example: WACC calculator
A user enters a representative set of values and assumptions.
- Key inputs
- Amounts, percentages, periods, and costs
- Apply the stated formula.
- Include all relevant entered values and constraints.
- Compare the result with an alternative scenario.
Result: WACC, component costs, capital weights, tax shield, scenarios, and structure comparisons.
Use the estimate as a planning input and verify important decisions with current records or qualified guidance.
Understanding your results
Primary estimate
WACC, component costs, capital weights, tax shield, scenarios, and structure comparisons.
Risk measures
Use supporting payment, leverage, cost, and cash figures together.
Assumptions
- Entered rates and costs remain constant.
- Payments and cash flows occur on schedule.
Limitations
- Taxes, legal terms, accounting treatment, and transaction-specific costs may differ.
- Future values, timing, and rates are uncertain.
Common mistakes
- Reviewing only the headline result.
- Ignoring relevant costs, timing, or supporting measures.
- Using optimistic timing or value assumptions.
- Treating an estimate as a guaranteed outcome.
Practical use cases
Compare scenarios consistently
Change one assumption at a time or enter each alternative using the same basis.
Plan cash requirements
Estimate funds needed before committing.
Planning and decision guide
Stress-test the assumptions
Prefer market values when available.
Review the important risks
Match the discount rate to cash-flow risk and currency.
Verify the source values
Do not assume more debt always lowers WACC; distress risk can raise required returns.
Frequently asked questions
What is WACC?
The weighted required return across debt and equity capital.
Why adjust debt cost for taxes?
Interest may create a tax shield under applicable rules.
Can WACC discount every project?
No. Projects with different risk may require adjusted rates.
Sources and review
- Introduction to investing — U.S. Securities and Exchange Commission. Accessed 2026-07-10.
Reviewed 2026-07-10.