Finance
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Weighted Average Cost of Capital Calculator.
Calculate WACC from market-value financing components, costs, and tax assumptions.
Set your values
Results update as you type.
Results are estimates from the stated formula and inputs; verify assumptions before making financial decisions.
FAQs
How is Weighted Average Cost of Capital calculated?
Market values and tax treatment must be supplied by the user.
Use Cases
Investment Appraisal
Use WACC as the discount rate to evaluate the net present value (NPV) of projects or acquisitions, ensuring they meet the required return.
Example: A company with WACC of 10% can reject a project with an expected return of 8%.
Capital Structure Optimization
Assess how changes in debt, equity, or preferred financing affect overall cost of capital, helping to find the optimal mix.
Example: Increasing debt from 30% to 50% may lower WACC due to tax benefits, but also increases financial risk.
Frequently Asked Questions
- What is WACC and why is it important?
- WACC (Weighted Average Cost of Capital) is the average rate a company expects to pay to finance its assets, blending the cost of debt, equity, and preferred stock. It's used as a discount rate for investment decisions and valuation.
- How does the tax rate affect WACC?
- Interest on debt is tax-deductible, so the after-tax cost of debt is lower. A higher tax rate reduces the cost of debt, thereby lowering WACC, all else equal.
- What inputs are needed for this calculator?
- You need the market values of debt, equity, and preferred capital, their respective costs (cost of debt, cost of equity, cost of preferred), and the corporate tax rate.
Tips & Common Mistakes
Tips
- Use market values (not book values) for debt and equity to reflect true economic weights.
- Ensure the cost of debt is the current market rate, not the historical coupon rate.
- The cost of equity can be estimated using CAPM: risk-free rate + beta * market risk premium.
- Double-check that the tax rate is the marginal corporate tax rate, not the effective rate.
Common Mistakes to Avoid
- Using book values instead of market values for capital weights.
- Forgetting to adjust the cost of debt for taxes (multiply by 1 - tax rate).
- Including short-term debt or other non-interest-bearing liabilities in the debt figure.
Last updated: August 13, 2026