Calculator
WACC calculator
Build a weighted average cost of capital from first principles — cost of equity under the capital asset pricing model, after-tax cost of debt, and the capital structure weights. Everything is calculated in your browser; nothing is uploaded or stored unless you choose to email yourself the result.
Written by CA Pranay Bhansali, Founder & Principal, Volaxi — Chartered Accountant (ICAI), former senior buy-side research analyst.
Last reviewed September 2026 · LinkedIn
WACC is the discount rate applied to unlevered free cash flow in a DCF. A one-point change in the rate routinely moves enterprise value by more than every other assumption combined — which is why the inputs deserve more scrutiny than the formula.
Inputs
Enter all rates as percentages and weights in any consistent units (they are normalised automatically).
Cost of equity (CAPM)
Cost of debt
Capital structure
Weighted average cost of capital
WACC
9.99%
- Cost of equity
- 11.70%
- After-tax cost of debt
- 6.00%
- Equity weight
- 70.00%
- Debt weight
- 30.00%
- Equity contribution
- 8.19%
- Debt contribution
- 1.80%
Indicative only. Not a valuation opinion and not advice.
01
Where WACC builds go wrong
The formula is arithmetic; the inputs are judgment. Most disputed discount rates in valuation reviews come down to beta selection, the size premium, and whether the capital structure weights reflect market values or a negotiated target.
Book-value weights
Weighting by balance-sheet values understates equity for any business trading above book. Use market values or a sustainable target structure.
Historical borrowing costs
The pre-tax cost of debt is the rate the business would pay to borrow today, not the coupon on debt raised years ago.
Unlevered beta discipline
Comparable-company betas must be unlevered at each company's gearing and relevered at the target structure. Skipping this step imports someone else's capital structure into your rate.
Growth and rate consistency
The perpetual growth rate in a terminal value must sit comfortably below the discount rate and below long-run nominal GDP growth.
Matching cash flow and rate
WACC discounts unlevered free cash flow. Discounting equity cash flows at WACC double counts the benefit of leverage.
02
Common questions
What is WACC?
The weighted average cost of capital is the blended rate of return a company must earn on its assets to satisfy both shareholders and lenders, weighted by the share of equity and debt in its capital structure. It is the standard discount rate for unlevered free cash flow in a DCF valuation.
How is the cost of equity calculated?
Cost of equity is built from the capital asset pricing model: the risk-free rate, plus beta multiplied by the equity risk premium. The risk-free rate is typically the yield on long-dated government bonds, beta measures the share price's sensitivity to the market, and the equity risk premium is the excess return investors demand for holding equities over risk-free bonds.
Why is the cost of debt multiplied by (1 − tax rate)?
Interest on debt is usually tax-deductible, so the effective cost of borrowing is reduced by the tax shield. A pre-tax cost of debt of 8% at a 25% tax rate costs the company 6% after tax. This shield is one reason moderate leverage lowers WACC.
What weights should be used in WACC?
Market values, not book values. Equity should be weighted at market capitalisation and debt at its market or estimated value. For a private company or a proposed transaction structure, use the target capital structure the business is expected to sustain rather than its current book gearing.
What is a typical WACC range?
For established listed companies in developed markets, WACC commonly falls between 7% and 11%. Smaller, private, or emerging-market businesses command higher rates — often 12% to 20% — reflecting size, liquidity, and country risk premia. The input matters less than whether every assumption behind it can be defended.
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