WACC & Cost of Capital Calculator
Calculate a company’s weighted average cost of capital using market-value debt and equity, tax-adjusted borrowing cost, and optional CAPM cost of equity.
Educational valuation tool only. Use market values, matching currency assumptions, and a sustainable target capital structure for decision-quality WACC.
Weighted average cost of capital
7.95%
(60.0% × 10.00%) + (40.0% × 4.88%)
Equity weight
60.00%
Debt weight
40.00%
After-tax debt cost
4.88%
CAPM / equity cost
10.00%
Tax shield reduces the 6.50% pre-tax debt cost to 4.88%. Total capital used: 10,000,000.
WACC sensitivity and capital mix
Test how a change in cost of equity moves the company discount rate, and review the current market-value capital structure.
WACC Calculator: Calculate Weighted Average Cost of Capital
This advanced WACC calculator estimates a company’s weighted average cost of capital, also known as cost of capital or corporate discount rate. Enter the market value of equity, interest-bearing debt, cost of equity, pre-tax cost of debt, and corporate tax rate. The calculator automatically derives market-value capital weights, after-tax debt cost, and the final WACC. You can also enable the CAPM option to calculate cost of equity from the risk-free rate, beta, and expected market return.
WACC is one of the most searched and widely used valuation metrics in corporate finance, DCF valuation, capital budgeting, equity research, mergers and acquisitions, and business appraisal. It represents the blended return that providers of debt and equity capital require. It is not a guaranteed investment return, and it should not be applied mechanically. Its usefulness depends on whether the cash flows, capital structure, currency, risk, and tax assumptions all fit the company or project being analysed.
WACC Formula
The weighted average cost of capital formula is WACC = (E ÷ V × Re) + (D ÷ V × Rd × (1 − T)). E is the market value of equity, D is the market value of interest-bearing debt, V is total capital or E plus D, Re is cost of equity, Rd is pre-tax cost of debt, and T is the corporate tax rate. The first term is the equity contribution; the second is the debt contribution after the interest tax shield.
For a simple example, assume a company has 60% equity, 40% debt, a 10% cost of equity, a 6.5% pre-tax debt cost, and a 25% tax rate. After-tax debt cost is 6.5% × (1 − 25%), or 4.875%. WACC is 60% × 10% plus 40% × 4.875%, equal to 7.95%. The calculator displays every component so the calculation can be checked and adjusted quickly.
How to Use This Cost of Capital Calculator
Start with market values where possible. For a public company, market value of equity is share price multiplied by diluted shares outstanding. Debt can be based on market value when observable, although book value is often used as a practical approximation for standard bonds and loans. Include interest-bearing borrowings; do not automatically include operating liabilities such as trade payables. Add equity and debt to calculate total capital, then let the calculator create the two capital weights.
Next, enter a pre-tax borrowing cost and the tax rate that is relevant to future taxable income. Enter a direct cost-of-equity assumption, or select CAPM to build it from its key inputs. Review the result as a base case, then change inputs to make low, central, and high WACC scenarios. In a valuation model, do not carry more precision than the evidence supports; a range such as 7.5% to 8.5% is often more honest than treating 7.95% as certain.
Cost of Equity in WACC
Cost of equity is the return shareholders require for accepting the risk of owning the business. It is normally higher than borrowing cost because shareholders are paid after lenders and bear more uncertainty. A common estimation method is the Capital Asset Pricing Model: cost of equity = risk-free rate + beta × market risk premium. The market risk premium equals expected market return minus risk-free rate.
This calculator provides both methods: enter a researched cost of equity directly, or switch on CAPM for a transparent estimate. A CAPM result is sensitive to the chosen beta, market risk premium, benchmark, time period, and currency. Private companies can use comparable public-company betas, but leverage adjustments and company-specific risk must be handled carefully. In every case, cost of equity is an assumption-based required return—not a forecast of the company’s next stock-market performance.
After-Tax Cost of Debt and the Tax Shield
Debt interest is commonly tax-deductible, so WACC uses after-tax cost of debt rather than the headline borrowing rate. The formula is after-tax debt cost = pre-tax debt cost × (1 − tax rate). A 7% pre-tax yield at a 25% tax rate becomes 5.25% after tax. This lower effective cost is known as the interest tax shield and is why tax-adjusted debt is included in the classic WACC formula.
The tax shield is not automatic in every situation. A loss-making company, a business with expiring tax credits, a company with limited interest deductibility, or an entity operating in multiple tax jurisdictions may not receive the full benefit immediately. Use a normalized marginal tax rate only when it matches the expected cash-flow period. For highly leveraged companies, also consider distress risk and whether debt cost could rise as additional borrowing is assumed.
Market Value Weights vs Book Value Weights
WACC normally uses market-value capital structure weights because market values reflect the current opportunity cost faced by investors. A public company’s equity market value can differ greatly from accounting book equity. Similarly, debt market value can diverge from face value when interest rates or credit quality change. Market weights are therefore generally the cleaner choice for a market-based valuation or discounted cash flow model.
Book values may still be used when market data is unavailable or the difference is immaterial. For private companies, an analyst may use target capital structure based on comparable companies, management plans, or a sustainable industry norm. The key is consistency: explain whether weights represent current financing, a target structure, or a peer benchmark, and ensure that the cost-of-equity and debt assumptions correspond to the same level of leverage.
WACC for DCF Valuation
In an enterprise-value discounted cash flow model, WACC is typically used to discount unlevered free cash flow—the cash flow available to both lenders and shareholders. The resulting present values and terminal value produce enterprise value. Net debt and other claims are then considered to arrive at equity value. When free cash flow grows, the discount rate has a powerful impact; a modest increase in WACC can reduce present value materially, especially in the terminal value.
Match the rate to the cash flow. Use a nominal WACC with nominal cash flows and a real WACC with real cash flows. Use a WACC in the same currency and inflation environment as the forecast. Do not discount equity cash flow with WACC; equity cash flow usually calls for cost of equity. Similarly, do not use a company-wide WACC for a project whose operating or country risk is materially different without making a risk adjustment.
Capital Budgeting and Project Hurdle Rates
Companies use cost of capital as a starting point for project hurdle rates. If a project’s expected internal rate of return exceeds an appropriately adjusted required return, it may create value; if it falls below, it may destroy value. WACC is often a useful company-wide benchmark for projects with risk similar to the existing business and financed within the normal capital structure.
A single company WACC is not suitable for every decision. A new venture, highly cyclical expansion, regulated investment, foreign subsidiary, or project with unusual operating leverage may need a project-specific discount rate. Analysts sometimes use a pure-play comparable-company approach to estimate project beta and capital cost. Practical investment decisions should also account for strategic fit, capacity constraints, scenario analysis, and risks that a single discount rate cannot summarize.
WACC Sensitivity Analysis
Sensitivity analysis is essential because WACC contains uncertain estimates. Change cost of equity, debt cost, tax rate, or capital structure one at a time, then observe the effect on WACC and DCF value. The chart on this page demonstrates the relationship between cost of equity and total WACC while holding other assumptions constant. A higher equity cost increases WACC most when equity is a large share of financing.
Build at least three valuation cases: a lower-rate case, a base case, and a higher-rate case. Avoid choosing a discount rate only because it delivers a desired valuation. Instead, document the source and rationale of every rate input and compare the implied valuation with trading multiples, precedent transactions, operating forecasts, and capital-market conditions. A decision that changes sharply under small WACC variations deserves extra attention.
Common WACC Calculation Mistakes
Frequent mistakes include using book equity when market equity is available, applying a pre-tax debt cost in the final formula, double-counting cash as negative debt, using a stale beta, and mixing decimal and percentage inputs. Another common error is using a cost of equity based on one country or currency with cash flows in another. A technically correct formula cannot fix mismatched inputs.
Analysts also sometimes use WACC with the wrong cash-flow definition. WACC belongs with unlevered free cash flow; cost of equity belongs with cash flow to equity. Be cautious when treating leases, preferred shares, minority interests, convertibles, pensions, or hybrid instruments, as each may require a separate treatment. A clear capital-structure bridge and a documented rate build-up prevent most practical errors.
What Is a Good WACC?
There is no universally good WACC. The right rate depends on business risk, industry, country, currency, leverage, size, expected inflation, credit quality, and conditions in capital markets. Stable companies with reliable cash flows may support a lower rate than early-stage, cyclical, small, leveraged, or politically exposed companies. Comparing WACC figures without matching these drivers can be misleading.
Rather than searching for one perfect WACC benchmark, develop a defensible range. Cross-check cost of equity with CAPM and comparable-company evidence, debt cost with current borrowing yields or credit spreads, and weights with market or target capital structure. If the output is surprisingly low or high, review the individual contributions. The calculation is most valuable as a transparent framework for judgment.
WACC FAQ and Disclaimer
What does WACC stand for? Weighted average cost of capital. Does WACC include tax? Yes, standard WACC applies the tax shield to debt cost. Is WACC the same as cost of equity? No. WACC blends the required return for both equity and debt based on their weights. Can WACC be negative? A conventional company WACC is usually positive; a negative result normally signals unusual or invalid assumptions that should be checked.
This free WACC calculator is for education and research only. It does not provide investment, tax, accounting, legal, lending, or valuation advice. Market data and model inputs can change, and results depend entirely on the assumptions entered. Verify calculations, assess relevant facts, and consult qualified professionals before making financial, corporate-finance, or investment decisions.
Frequently Asked Questions
What is the WACC formula?
WACC = (equity ÷ total capital × cost of equity) + (debt ÷ total capital × pre-tax cost of debt × (1 − tax rate)).
Why is debt cost adjusted for tax?
Interest can be tax-deductible, so the effective cost of debt is often lower than the stated pre-tax borrowing rate.
Should I use market value or book value for WACC?
Market-value weights are generally preferred because they reflect the current opportunity cost of capital.
Is WACC used to discount DCF cash flows?
Yes. WACC is commonly used to discount unlevered free cash flow in an enterprise-value DCF, when the rate matches the cash flow risk.