WACC Calculator - Weighted Average Cost of Capital
Use this WACC calculator to estimate weighted average cost of capital from equity, debt, preferred stock, and tax rate for valuation review.
WACC Calculator
Results
What Is a WACC Calculator?
A WACC calculator estimates the weighted average cost of capital, which is the blended return a company must provide to its capital providers. Use it when a discounted cash flow model needs a discount rate, a project team needs a hurdle rate, a board memo needs a capital structure check, or an analyst wants to compare an investment return against the company's financing cost.
- • DCF discount rate: Match the discount rate in a discounted cash flow model with the WACC estimate from the same capital structure.
- • Project hurdle rate: Compare a project's expected return with the WACC benchmark before approving new capital spending.
- • Capital structure review: Test how more debt, less equity, or a preferred stock layer changes the blended WACC rate.
- • Debt tax shield check: Separate the pre-tax borrowing rate from the after-tax cost of debt that belongs in the WACC formula.
The result is an estimate, not a promise. It depends on the values you enter and the assumptions behind the cost of equity, the pre-tax cost of debt, and the corporate tax rate. Two teams can compute different WACC values for the same company and still both be doing the math correctly if they pick different inputs.
Read WACC as a finance assumption that needs review. If the calculator returns 9.6% for a project with a 7% expected return, the gap becomes a discussion about risk, leverage, and timing rather than a verdict on the project itself.
How the WACC Calculator Works
The calculator uses the standard weighted average cost of capital formula. Each funding source gets a weight based on its share of total capital, then the calculator multiplies that weight by the required return for that source. The debt contribution is reduced by the tax shield because interest expense is commonly tax deductible in WACC analysis.
- E: Market value of common equity.
- D: Market value or documented estimate of interest-bearing debt.
- P: Market value of preferred stock, or zero if the company has none.
- V: Total capital, equal to E plus D plus P.
- Re, Rd, Rp: Cost of equity, pre-tax cost of debt, and cost of preferred stock.
- T: Marginal corporate tax rate used for the debt tax shield.
The formula is a weighted average, but the weights should describe the financing mix being analyzed. A business with $8 million of equity and $2 million of debt is 80% equity funded and 20% debt funded, so equity drives most of the WACC result.
The output is only useful if the inputs are consistent. Avoid mixing market-value equity with book-value debt, and keep the analysis date matched across the capital values and the component costs.
Worked Example
Equity is $8,000,000, debt is $2,000,000, preferred stock is $0, cost of equity is 11%, pre-tax cost of debt is 5.5%, and the corporate tax rate is 25%.
Total capital is $10,000,000. Equity weight is 80%, debt weight is 20%, and after-tax cost of debt is 5.5% x (1 - 25%) = 4.125%. WACC = 80% x 11% + 20% x 4.125%.
The WACC estimate is 9.625%.
Use 9.625% as the blended financing-cost benchmark for this input set, then rerun the calculator with a different capital mix to see how the WACC moves.
According to OpenStax Principles of Finance, weighted average cost of capital is calculated from the weights and costs of debt, preferred stock, and common equity, with debt measured on an after-tax basis.
If the debt input needs a separate tax-shield check, After-Tax Cost Of Debt Calculator focuses on that component before it enters the WACC formula.
Key Concepts Explained
The WACC result is easier to review when the inputs are separated into capital values, component costs, and the tax shield. These four ideas drive most WACC errors in practice.
Capital weights
Weights show how much each funding source contributes to total capital. A small preferred stock balance has a small WACC effect, while a large debt balance can pull the blended rate toward the after-tax cost of debt when leverage is meaningful.
After-tax cost of debt
The debt component of WACC uses the pre-tax borrowing cost multiplied by one minus the tax rate. This keeps debt comparable with equity and preferred stock in an after-tax valuation framework.
Cost of equity
Cost of equity is the return common shareholders require for the business risk they absorb. It is usually higher than the debt cost because common equity takes the first loss when company performance weakens.
Total capital and WACC
Total capital is the sum of equity, debt, and preferred stock used in the WACC formula. The same WACC number can hide different funding mixes, so the calculator shows the weights alongside the result.
The calculator surfaces each weight because a single WACC number can hide the reason it moved. If the rate rises, the cause may be a higher cost of equity, a smaller debt tax shield, or a shift toward a more expensive funding source.
When the cost of equity input comes from market data, CAPM Calculator helps review the beta and risk premium that sit behind the rate.
How to Use This Calculator
Use one consistent date and one consistent capital structure convention. The WACC calculator is most useful when the debt, equity, preferred stock, and rate assumptions all describe the same scenario.
- 1 Enter market value of equity: Use market capitalization for a public company or a documented equity value estimate for a private company.
- 2 Enter market value of debt: Use interest-bearing debt. If market debt value is not available, keep a note explaining the estimate so the WACC can be reviewed.
- 3 Add preferred stock if used: Enter the market value of preferred stock. If the company has no preferred stock, leave the value at zero.
- 4 Enter component costs: Use the cost of equity, pre-tax cost of debt, and preferred stock cost that match the same analysis date as the capital values.
- 5 Set the corporate tax rate: Use a marginal, statutory, or planning tax rate, and document the choice so the after-tax debt cost can be traced back to the assumption.
- 6 Review WACC and weights: Check the WACC, capital weights, after-tax cost of debt, and debt-to-equity ratio before using the number in a model.
A finance manager comparing two plant upgrades enters the company's current capital mix, then reruns the calculation with a higher pre-tax cost of debt to see whether a refinancing scenario changes WACC enough to affect the recommendation.
After the WACC assumption is set, DCF Calculator applies a discount rate view inside a full cash flow valuation workflow.
Benefits of Using This Calculator
A WACC estimate is most useful when the math is transparent. The calculator keeps the component rates and weights visible so a reviewer can challenge the assumptions instead of reverse-engineering the answer.
- • Standardized discount rate: Use the same WACC across DCF models, terminal value checks, and sensitivity tables for consistent valuation work.
- • After-tax debt visibility: See the after-tax cost of debt separately, which helps catch mistakes where a pre-tax borrowing rate was used directly in the WACC formula.
- • Capital mix review: Test how more debt, less equity, or a preferred stock issuance changes the blended WACC rate before recommending the change.
- • Hurdle-rate check: Compare expected project returns with a WACC benchmark before moving to a longer capital request or board memo.
- • Audit trail support: Keep the WACC inputs aligned with a memo, spreadsheet, or investment committee model for review later.
This helps when several teams use the same business case. Operations may focus on cash savings, accounting may focus on tax effects, and finance may focus on the discount rate, and showing the WACC components gives everyone the same starting point for review.
For value creation review, ROIC Calculator shows whether the operating return clears the WACC financing cost.
Factors That Affect WACC Results
WACC can move even when operating forecasts do not change. Capital market conditions, debt pricing, tax assumptions, and the chosen capital structure all affect the output.
Market value vs book value
Market values usually reflect current investor expectations better than old book values. A large change in share price can shift the equity weight in WACC even if the balance sheet has not changed much.
Tax rate choice
The tax rate controls the debt tax shield. A statutory rate, blended rate, or marginal planning rate can produce different after-tax cost of debt values in the WACC formula.
Cost of equity estimation
Higher operating risk usually raises the cost of equity, which can dominate WACC when equity is the largest capital source in the mix.
Industry WACC benchmarks
WACC inputs differ across sectors, so the WACC for a utility is usually lower than for a software company at the same point in time.
- • The calculator does not estimate beta, risk-free rates, credit spreads, or market risk premiums. It assumes you already have support for the cost of equity, the pre-tax cost of debt, and the corporate tax rate.
- • The result is a finance estimate for review, not investment advice. It should be tested with sensitivity cases before use in a major capital decision or a published valuation.
Update the inputs when the market changes, when the company refinances, or when the analysis shifts from a whole-company valuation to a project with a different risk profile.
According to NYU Stern Damodaran, WACC inputs are tracked by sector and updated in January 2026, which is why WACC assumptions should be reviewed against current market data.
According to SEC Investor.gov, weighted average cost of capital is a blended financing cost used to describe how a company funds itself through debt and equity.
If the cost of equity needs a fresh market-based estimate, Beta Stock Calculator covers the beta assumption that drives that rate.
Frequently Asked Questions
Q: What is the WACC formula?
A: WACC equals the equity weight times the cost of equity plus the debt weight times the pre-tax cost of debt times one minus the tax rate plus the preferred stock weight times the cost of preferred stock. Each weight is the share of total capital for that source.
Q: What is a good WACC value?
A: There is no single good WACC. The right value depends on the business risk, the capital structure, the tax rate, and the cost of equity, and it should be compared with the expected return of the project or investment being reviewed.
Q: How do you calculate WACC in Excel?
A: Put the equity value, debt value, preferred stock value, cost of equity, pre-tax cost of debt, preferred stock cost, and tax rate in cells, then compute each capital weight as the value divided by total capital, the after-tax cost of debt as the pre-tax cost times one minus the tax rate, and the WACC as the sum of weight times cost across sources.
Q: Why is the debt cost adjusted for taxes in WACC?
A: Interest expense is commonly tax deductible, so the effective cost of debt to the company is the pre-tax borrowing rate multiplied by one minus the tax rate. The WACC formula uses that after-tax rate to keep debt comparable with equity and preferred stock in the same after-tax valuation framework.
Q: Should WACC use market or book value weights?
A: Market value weights are usually preferred for valuation because they reflect current investor expectations. Book values may be used for internal policy or for private companies where market values are hard to estimate, but the choice should be documented and applied consistently across debt, equity, and preferred stock.
Q: What is the difference between WACC and cost of capital?
A: WACC is the most common company-wide cost of capital measure, calculated as a weighted average across capital sources. A project can still need a different hurdle rate if its risk is meaningfully higher or lower than the overall business.