After-Tax Weighted Average Cost of Capital (WACC) Calculator

Enter your capital structure values, component costs, and tax rate to calculate after-tax WACC, the debt tax shield benefit, and alternative cost-of-equity estimates.

Created by Luis GonzalezLast updated: June 9, 2026

How to Use This Calculator

1
Input Market Value of Equity
Enter the total market value of the company's common equity (shares outstanding × share price).
2
Specify Market Value of Debt
Provide the total market value of all interest-bearing debt obligations, including bonds and loans.
3
Input Market Value of Preferred Stock
Enter the total market value of preferred shares outstanding. Input 0 if the company has no preferred stock.
4
Enter Cost of Equity
Input the required return on equity, which can be derived from CAPM, DDM, or management's estimate.
5
Specify Pre-Tax Cost of Debt
Provide the weighted average interest rate on all debt before applying any tax shield.
6
Input Cost of Preferred Stock
Enter the cost of preferred stock, calculated as the preferred dividend divided by its market price.
7
Specify Corporate Tax Rate
Provide the effective or marginal corporate income tax rate used for the debt tax shield.
8
Optionally Expand CAPM & DDM Inputs
Click 'Show CAPM & DDM inputs' to enter Risk-Free Rate, Market Risk Premium, Beta, Dividend Yield, and Dividend Growth Rate for alternative cost-of-equity estimates.
9
Review Your WACC and Component Costs
Examine the After-Tax WACC, After-Tax Cost of Debt, Tax Shield Benefit, CAPM Cost of Equity, and DDM Cost of Equity. The Capital Structure Analysis panel shows unlevered cost of capital, D/E ratio context, and a visual breakdown of capital weights.

Example Calculation

A public company with $5M equity, $2M debt, and $0.5M preferred stock needs to calculate its WACC with a 12% cost of equity, 8% pre-tax cost of debt, 10% cost of preferred stock, and a 25% corporate tax rate.

Market Value of Equity ($)

5,000,000

Market Value of Debt ($)

2,000,000

Market Value of Preferred Stock ($)

500,000

Cost of Equity (%)

Pre-Tax Cost of Debt (%)

Cost of Preferred Stock (%)

Corporate Tax Rate (%)

Results

After-Tax WACC

10.27%

After-Tax Cost of Debt

6.00%

Tax Shield Benefit

0.53%

CAPM Cost of Equity

10.20%

DDM Cost of Equity

6.00%

Insights card shows capital structure analysis with unlevered cost of capital, D/E ratio, and capital weights breakdown.

Tips

Use Market Values, Not Book Values

Always use the market values of equity, debt, and preferred stock when calculating WACC. Book values do not reflect current market conditions and can lead to inaccurate WACC estimates for valuation.

Regularly Update Inputs

WACC is not static. Market interest rates, equity risk premiums, and capital structure change over time. Recalculate WACC quarterly or annually to keep valuation models and investment decisions current.

Focus on Marginal Costs

For evaluating new projects, use the marginal cost of new debt and equity rather than historical averages. The cost of raising new capital may differ from existing capital.

Compare CAPM and DDM Estimates

Expand the CAPM & DDM inputs to compare alternative cost-of-equity estimates. If they diverge significantly (e.g., CAPM 10.2% vs DDM 6%), review your assumptions — the Capital Structure Analysis insight will flag this.

Mastering Capital Structure with the After-Tax WACC Calculator

The After-Tax WACC Calculator provides a comprehensive assessment of a company's overall financing cost by weighting the costs of equity, debt, and preferred stock while incorporating the debt tax shield. It also compares CAPM and DDM approaches for cost of equity estimation. WACC typically ranges from 8% to 12% for established companies in 2026 and serves as the discount rate for valuing future cash flows and evaluating new investment projects.

WACC's Role in Corporate Valuation

WACC serves as the primary discount rate for a company's free cash flows to the firm (FCFF) in discounted cash flow (DCF) models. It represents the minimum return a company must generate to satisfy all capital providers. A WACC of 10.27% means any project yielding less than 10.27% will destroy shareholder value, making it a crucial hurdle rate for capital allocation.

WACC is also compared against return on invested capital (ROIC) — when ROIC exceeds WACC, the company is creating value. When ROIC falls below WACC, capital is being deployed inefficiently.

The Comprehensive WACC Calculation

Total Capital = Market Value of Equity (E) + Market Value of Debt (D) + Market Value of Preferred Stock (P)
Weight of Equity (We) = E / Total Capital
Weight of Debt (Wd) = D / Total Capital
Weight of Preferred Stock (Wp) = P / Total Capital

After-Tax Cost of Debt = Pre-Tax Cost of Debt × (1 - Corporate Tax Rate / 100)

WACC = (We × Cost of Equity) + (Wd × After-Tax Cost of Debt) + (Wp × Cost of Preferred Stock)

The calculator also determines cost of equity using both models:

CAPM Cost of Equity = Risk-Free Rate + Beta × Market Risk Premium
DDM Cost of Equity = Dividend Yield + Dividend Growth Rate

💡 To further refine your understanding of capital structure, our Relative Valuation Calculator helps compare your company's metrics against peers.

Worked Example: Determining a Company's After-Tax WACC

A company has a Market Value of Equity of $5,000,000, Market Value of Debt of $2,000,000, and Market Value of Preferred Stock of $500,000. The Cost of Equity is 12%, Pre-Tax Cost of Debt is 8%, and Cost of Preferred Stock is 10%. The Corporate Tax Rate is 25%.

Calculate Total Capital: $5,000,000 + $2,000,000 + $500,000 = $7,500,000
Calculate Component Weights: We = $5M / $7.5M = 66.67% Wd = $2M / $7.5M = 26.67% Wps = $0.5M / $7.5M = 6.67%
Calculate After-Tax Cost of Debt: 8% × (1 - 0.25) = 6.00%
Calculate After-Tax WACC: (0.6667 × 12%) + (0.2667 × 6.00%) + (0.0667 × 10%) = 8.00% + 1.60% + 0.67% = 10.27%

The After-Tax WACC is 10.27%, meaning the company needs to earn at least 10.27% on new investments to create shareholder value.

💡 To assess potential future risks to your capital, our Reinvestment Risk Calculator can help evaluate the impact of changing interest rates on your returns.

Interpreting WACC for Business Decisions

WACC serves as a hurdle rate: projects with expected returns below WACC destroy shareholder value. A WACC of 10.27% means every dollar of new capital must generate more than $0.1027 in annual returns.

The tax shield is a key lever — at a 25% tax rate, the 8% pre-tax cost of debt drops to 6%, saving 0.53 percentage points on WACC compared to an all-equity structure. However, increasing leverage also increases financial risk, which may raise both the cost of debt and equity at higher debt levels.

Corporate finance teams should recalculate WACC regularly, as it fluctuates with market interest rates, equity risk premiums, and changes in capital structure. Comparing CAPM and DDM estimates for cost of equity provides a useful sanity check — significant divergence between the two models suggests reviewing underlying assumptions.

Frequently Asked Questions

What is After-Tax WACC?

After-Tax WACC is the average rate of return a company pays to all its capital providers — stockholders, preferred stockholders, and bondholders — after accounting for the tax deductibility of interest expenses. For example, a company with 66.7% equity at 12%, 26.7% debt at 8% (6% after tax), and 6.7% preferred at 10% has a WACC of 10.27%.

Why is the cost of debt adjusted for taxes?

Interest payments on debt are tax-deductible, creating a 'tax shield' that reduces the effective cost of debt. At a 25% tax rate, an 8% pre-tax cost of debt becomes 6% after tax (8% × 0.75). Equity dividends and preferred dividends are not tax-deductible, so their costs are not adjusted.

What is a good WACC?

WACC varies by industry and risk profile. Established companies typically have WACCs of 8-12%, while startups or high-risk firms may see 15-25%. A WACC of 10.27% means any project must return more than 10.27% to create shareholder value. Lower WACC generally signals a more efficient capital structure.

What is the difference between CAPM and DDM cost of equity?

CAPM (Capital Asset Pricing Model) uses Risk-Free Rate + Beta × Market Risk Premium to estimate cost of equity based on systematic risk. DDM (Dividend Discount Model) uses Dividend Yield + Growth Rate based on expected dividend payments. They often produce different estimates — CAPM reflects market risk pricing while DDM reflects expected cash returns to shareholders.

How does capital structure affect WACC?

Increasing debt relative to equity typically lowers WACC because debt is cheaper than equity (interest is tax-deductible and creditors have priority in bankruptcy). However, excessive debt increases financial risk, which raises both the cost of debt and equity. The optimal capital structure minimizes WACC by balancing the tax shield benefit against increased bankruptcy risk.