How to Use WACC Calculator
The WACC Calculator blends the cost of equity and after-tax cost of debt according to their weights in the capital structure.
- Enter market value of equity (E) — Usually market capitalisation for public companies.
- Enter market value of debt (D) — Prefer market value of debt; if unavailable, book value is a common proxy.
- Enter cost of equity (Re) — Often computed via CAPM: Rf + β × ERP.
- Enter cost of debt (Rd) — Use the yield to maturity on outstanding debt, not the coupon rate.
- Enter the tax rate (Tc) — The marginal effective corporate tax rate.
- Read the Result — The WACC Calculator instantly displays WACC, the weights, and the after-tax cost of debt.
Formula & Theory — WACC Calculator
The WACC Calculator uses the textbook weighted-average formula:
V = E + D
WACC = (E / V) × Re + (D / V) × Rd × (1 − Tc)| Symbol | Meaning |
|---|---|
| E | Market value of equity |
| D | Market value of debt |
| V | Total capital (E + D) |
| Re | Cost of equity |
| Rd | Pre-tax cost of debt |
| Tc | Corporate tax rate |
Two intuition points:
- The tax shield reduces the effective debt cost, which is why companies with stable cash flows often add leverage to lower WACC.
- Adding debt initially lowers WACC, but beyond a point increases the cost of both debt and equity as financial distress risk rises, eventually pushing WACC back up.
Use Cases for WACC Calculator
- DCF valuation — Apply WACC as the discount rate on free cash flow to the firm.
- Capital budgeting — Reject projects whose IRR is below WACC; accept those above it (subject to risk adjustments).
- Capital structure analysis — Test how rebalancing debt and equity affects the firm’s overall cost of capital.
- Performance measurement — Compare ROIC vs WACC to determine economic value added (EVA).
- M&A pricing — Estimate the standalone WACC of the target and the post-deal combined entity.
- Regulated industries — Utilities and infrastructure regulators rely on WACC to set allowed rates of return.
The WACC Calculator therefore underpins both day-to-day investment decisions and high-stakes valuation work.