Weighted Average Cost of Capital (WACC)
Calculate WACC: the blended cost of equity and debt financing.
Essential for corporate valuation and investment decisions.
The Formula
The Weighted Average Cost of Capital (WACC) represents the average rate of return a company must earn on its existing assets to satisfy all of its investors — both equity shareholders and debt holders. It is the blended cost of all sources of financing, weighted by their proportions in the company's capital structure.
WACC is one of the most important concepts in corporate finance. It serves as the discount rate in discounted cash flow (DCF) analysis, the primary method used by investment bankers, analysts, and corporate managers to value companies and evaluate investment projects. A project should only be undertaken if its expected return exceeds the company's WACC, because otherwise it destroys shareholder value.
The formula has two main components. The first term (E/V) × Re captures the cost of equity — the return that shareholders expect. This is often estimated using the Capital Asset Pricing Model (CAPM). The second term (D/V) × Rd × (1 − T) captures the after-tax cost of debt. The (1 − T) factor accounts for the tax deductibility of interest payments, which makes debt cheaper than it appears on the surface. This tax shield is one of the main reasons companies use debt financing.
The weights E/V and D/V represent the proportion of the company's value financed by equity and debt respectively. V equals E plus D, so the weights always sum to 1. In practice, analysts often use market values rather than book values for these weights, as market values better reflect current economic reality.
A typical WACC for a large, established company might be 7 to 12 percent. Startups and high-risk businesses have higher WACCs because investors demand greater returns to compensate for the risk. Utilities and other stable businesses tend to have lower WACCs. Changes in interest rates, tax policy, or a company's risk profile will all shift the WACC, which in turn affects how the company and its projects are valued.
Understanding WACC helps explain why companies carefully manage their mix of debt and equity. Too much debt increases financial risk and can raise the WACC. Too little debt means missing out on the tax benefit of interest deductions. The optimal capital structure minimizes WACC and maximizes firm value.
Variables
| Symbol | Meaning |
|---|---|
| WACC | Weighted average cost of capital (%) |
| E | Market value of equity (currency) |
| D | Market value of debt (currency) |
| V | Total value of financing: V = E + D (currency) |
| Re | Cost of equity — expected return for shareholders (%) |
| Rd | Cost of debt — interest rate on borrowings (%) |
| T | Corporate tax rate (decimal or %) |
Example 1
A company has $60 million in equity and $40 million in debt. The cost of equity is 10%, the cost of debt is 5%, and the corporate tax rate is 25%. Calculate the WACC.
V = $60M + $40M = $100M. E/V = 0.60, D/V = 0.40
WACC = (0.60 × 10%) + (0.40 × 5% × (1 − 0.25))
WACC = 6.0% + (0.40 × 3.75%) = 6.0% + 1.5%
WACC = 7.5%
Example 2
A startup has $8 million in equity and $2 million in debt. Cost of equity is 18%, cost of debt is 8%, and the tax rate is 21%. Find the WACC.
V = $8M + $2M = $10M. E/V = 0.80, D/V = 0.20
WACC = (0.80 × 18%) + (0.20 × 8% × (1 − 0.21))
WACC = 14.4% + (0.20 × 6.32%) = 14.4% + 1.264%
WACC = 15.66%
When to Use It
WACC is used throughout corporate finance and investment analysis as the benchmark discount rate.
- Discounted cash flow (DCF) valuation of companies
- Evaluating whether a new project or acquisition will create value
- Comparing the cost of different financing strategies (more debt vs. more equity)
- Setting hurdle rates for capital budgeting decisions
- Investment banking analysis for mergers, acquisitions, and IPOs
- Academic finance courses covering capital structure and valuation theory