WACC Calculator
Calculate WACC, after-tax debt cost, capital weights, and contribution bridge from your financing assumptions so you can compare discount-rate and hurdle-rate scenarios before valuation or capital budgeting decisions.
WACC Inputs
Quick Presets
WACC Summary
Weighted average cost of capital
10.50%
Elevated Cost of Capital. Capital is relatively expensive; project hurdle rates and assumptions should be stress-tested.
Total capital
$10B
After-tax debt cost
4.50%
Equity weight
80.00%
Debt weight
20.00%
Capital Mix Breakdown
| Source | Market value | Weight | Cost used | Contribution |
|---|---|---|---|---|
| Equity | $8,000,000,000 | 80.00% | 12.00% | 9.60% |
| Debt | $2,000,000,000 | 20.00% | 6.00% -> 4.50% after tax | 0.90% |
| Preferred stock | $0 | 0.00% | 8.00% | 0.00% |
| Total | $10,000,000,000 | 100.00% | -- | 10.50% |
Current-Input Bridge
Formula line
(80.00% x 12.00%) + (20.00% x 6.00% x (1 - 25.00%)) + (0.00% x 8.00%) = 10.50%
What to test next
- Equity is the largest contributor in this scenario at 9.60%, so that assumption set deserves the first sensitivity check.
- Debt remains a meaningful but not dominant funding source at 20.00% of capital.
- Preferred stock has zero weight in this scenario, so only equity and debt drive the blended hurdle rate.
Sensitivity Scenarios
| Scenario | Cost of equity | Cost of debt | Tax rate | WACC | Delta vs base |
|---|---|---|---|---|---|
| Base Case | 12.00% | 6.00% | 25.00% | 10.50% | 0.00% |
| Higher Risk Premium | 13.00% | 6.50% | 25.00% | 11.38% | +0.88% |
| Lower Rate Environment | 11.00% | 5.25% | 25.00% | 9.59% | -0.91% |
| Tax Shield Upside | 12.00% | 6.00% | 30.00% | 10.44% | -0.06% |
Editorial & Review Information
Reviewed on: 2026-03-24
Published on: 2025-09-23
Author: LumoCalculator Editorial Team
What we checked: We re-checked the WACC formula mapping, the example arithmetic, the meaning of each result label, and the accessibility of the listed references.
Purpose and scope: This page supports educational discount-rate planning, DCF setup, and financing-mix comparison. It does not provide underwriting decisions, issuer recommendations, or personalized investment advice.
How to use this review: Start with one base capital structure, then run higher and lower cost cases to see which assumption drives the biggest WACC change before using the result in valuation or hurdle-rate decisions.
Financial Disclaimer
WACC is highly assumption-sensitive. Real outcomes can differ because capital structure, borrowing spreads, tax shields, market conditions, and project risk can change after you set the inputs. Use this calculator as a scenario framework rather than a substitute for full valuation or risk diligence.
Use Scenarios
DCF discount-rate baseline
Use WACC as a baseline discount rate for unlevered free-cash-flow valuation, then test the present-value impact with the NPV Calculator before locking in a hurdle rate.
Capital budgeting hurdle design
Translate financing mix and component costs into a required-return threshold before approving projects, acquisitions, or long-cycle investments.
Leverage and tax policy stress test
Compare how debt mix and tax assumptions alter after-tax capital cost to evaluate whether a lower blended rate is coming from durable financing efficiency or from more leverage risk.
Formula Explanation
Core WACC formula
WACC = (E/V x Re) + (D/V x Rd x (1 - T)) + (P/V x Rp)
E, D, P are market values of equity, debt, and preferred stock. V is total capital. Re, Rd, Rp are the required returns for each funding source, and T is the tax rate used for the debt tax shield.
Weights and cost inputs
WACC is usually built from market-value weights because the goal is to estimate a forward-looking hurdle rate, not to restate a historical balance sheet. If you are estimating the equity spread as a CAPM input, compare the assumption set with the Risk Premium Calculator.
Debt tax shield and preferred stock
After-tax debt cost = Rd x (1 - T)
Debt is reduced by the tax shield when interest is deductible, but the realized benefit can be smaller if deduction limits or low taxable income apply. Preferred stock is not tax-adjusted in this formula, so its expected return flows straight into the blend when the preferred layer is material.
Example Cases
Case 1: Large-cap tech profile
Inputs
- Capital mix: Equity $90B, Debt $10B, Preferred $0
- Component costs: Re 11.5%, Rd 5.2%, Rp 8.0%
- Tax rate: 21%
Computed Results
- WACC: 10.76%
- After-tax debt cost: 4.11%
- Weights: Equity 90.00%, Debt 10.00%
- Contribution bridge: Equity 10.35%, Debt 0.41%
Interpretation
Equity dominates the hurdle rate, so valuation sensitivity is driven more by equity risk premium assumptions than by debt-spread changes.
Decision Hint
Focus governance on beta/risk-premium calibration and growth-duration assumptions in DCF work.
Case 2: Regulated utility profile
Inputs
- Capital mix: Equity $18B, Debt $22B, Preferred $1B
- Component costs: Re 8.1%, Rd 4.8%, Rp 6.5%
- Tax rate: 25%
Computed Results
- WACC: 5.65%
- After-tax debt cost: 3.60%
- Weights: Equity 43.90%, Debt 53.66%, Preferred 2.44%
- Contribution bridge: Equity 3.56%, Debt 1.93%, Preferred 0.16%
Interpretation
Lower component costs and a meaningful tax-shielded debt weight keep capital cost comparatively low for long-duration asset programs.
Decision Hint
Stress-test refinancing scenarios because debt share is high even when base WACC looks favorable.
Case 3: Private leveraged transaction
Inputs
- Capital mix: Equity $2.5B, Debt $3.5B, Preferred $0
- Component costs: Re 15.0%, Rd 8.2%, Rp 8.0%
- Tax rate: 26%
Computed Results
- WACC: 9.79%
- After-tax debt cost: 6.07%
- Weights: Equity 41.67%, Debt 58.33%
- Contribution bridge: Equity 6.25%, Debt 3.54%
Interpretation
Tax shield helps, but elevated equity and debt costs keep the hurdle high enough to require disciplined underwriting and tighter downside controls.
Decision Hint
Use conservative exit and cash-flow assumptions, then test covenant and rate-shock resilience.
Boundary Conditions
How to Read the Result
Start with the WACC headline
Use the headline WACC as a base hurdle rate for cash flows that look like the company's core business. A higher WACC means future cash flows need more return to clear the bar.
Watch the contribution mix
The contribution bridge shows whether equity assumptions, borrowing cost, or preferred stock is doing most of the work. The largest contributor is usually the first input to stress-test.
Adjust when project risk changes
If a project has different country risk, leverage, duration, currency exposure, or execution risk than the core business, treat company WACC as a starting point rather than the final discount rate.
Sources & References
- BDC - Weighted Average Cost of CapitalUsed for the definition of WACC, its blended-cost framing, and the discount-rate role in capital budgeting and valuation.
- IRS - Limitation on the Deduction for Business Interest ExpenseUsed for the tax-shield caveat that interest deductibility can be limited in practice instead of always flowing through one-for-one.
- NYU Stern - Damodaran Cost of Capital by SectorUsed for sector benchmarking context when comparing market-value weights, cost-of-equity ranges, and blended capital-cost assumptions.
- U.S. Department of Transportation - Value for Money Assessment PrimerUsed for discount-rate decision context and why project-specific risk can justify a different rate than one firm-level WACC.