How do you calculate WACC for a startup?

For a startup, WACC is dominated by the cost of equity because most early-stage companies carry little or no debt. Use the CAPM formula: risk-free rate + beta x equity risk premium. Since startups lack a traded stock, estimate beta by averaging the unlevered betas of comparable public companies in the same sector, then re-lever for your target capital structure. Add a size premium (typically 3-6%) and, optionally, a company-specific risk premium (2-5%) to account for execution risk, key-person dependency, and limited operating history.

What beta should I use for a startup WACC?

Startups do not have observable betas. The standard approach is to find a peer group of public companies in the same industry, compute their unlevered (asset) betas, and take an average. Then re-lever that beta using your startup expected debt-to-equity ratio. For software and SaaS startups, sector unlevered betas typically range from 1.0 to 1.5. For biotech or hardware, they can reach 1.5 to 2.0. Using a higher beta produces a higher cost of equity and a more conservative (lower) valuation.

What is a typical WACC range for a pre-revenue startup?

Pre-revenue startups are typically discounted at 20-40%, with seed-stage companies often at the high end. Series A/B companies with demonstrated product-market fit commonly use 15-25%. Late-stage growth-equity targets like Stripe or Databricks may sit at 12-18%. These rates are far above the 8-12% WACC seen for large-cap public companies because they incorporate substantial execution risk, illiquidity, and the probability of failure.

Should I use book value or market value weights in a startup WACC?

Always use market value weights. For the equity component, use the post-money valuation from the latest funding round as the market value of equity. For debt, use the face value of any outstanding convertible notes or term loans. Most early-stage companies have very low debt weights (under 10%), so the cost of equity almost entirely determines WACC.

How do you handle convertible notes and SAFEs in the capital structure?

Convertible notes and SAFEs (Simple Agreements for Future Equity) sit ambiguously between debt and equity. For pre-priced rounds, treat them as quasi-equity at the expected conversion price; for outstanding convertible notes with explicit interest rates, treat the face value as debt during the period before conversion. The size of these instruments is typically small relative to total enterprise value, so the choice rarely shifts WACC by more than 0.5 percentage points.

What is the venture capital method, and how does it relate to startup WACC?

The VC method works backward from a target exit valuation and required IRR. If a VC wants a 10x return over 5 years on a Series A investment, the implied IRR is approximately 58% annually. That number is effectively the discount rate applied to the startup expected cash flows, which is a far higher number than a CAPM-derived WACC would produce. Both methods can be reconciled by recognizing that the VC method embeds an explicit probability-of-failure adjustment; the WACC method treats expected cash flows on an unweighted basis.

How does the size premium work for startup valuations?

The size premium reflects the historical observation that smaller-cap companies have delivered higher returns than the broad market on average, even after adjusting for beta. Duff & Phelps publishes size premium tables ranging from approximately 1% for mid-cap to 6%+ for micro-cap. For private startups, the appropriate size premium is typically the highest band (6%+), reflecting both the small size and the additional illiquidity discount. Add this to the CAPM cost of equity to derive the startup-adjusted discount rate.

How should WACC change as a startup matures?

WACC should decline as the company de-risks. Seed stage 25-35%. Series A 20-25%. Series B/C 15-20%. Pre-IPO growth equity 12-15%. Post-IPO 9-11%. The decline reflects reduced execution risk, more diversified revenue, lower probability of failure, and improved access to debt markets. A useful sanity check: does your modeled WACC trajectory align with the actual round-over-round multiples paid by sophisticated investors? If a Series B was priced at 12x revenue and yours implies 6x, your WACC may be too high.

WACC Calculator for Startups

By Javier Sanz, Founder & Lead AnalystEditorially reviewed

Last updated: May 21, 2026Reviewed by: Javier Sanz

TL;DR

For a startup, WACC is almost entirely cost of equity. Anchor on a public-peer unlevered beta, re-lever for your structure, then add a size premium (3-6%) and a company-specific risk premium (2-5%). Typical ranges: seed 25-35%, Series A 20-25%, late-stage growth (Stripe, Databricks) 12-18%. WACC should decline as the company de-risks.

Why startup WACC is fundamentally different

Estimating WACC for a startup is fundamentally different from computing it for a public company. With no traded stock, no observable beta, and often no debt, the cost of equity drives almost the entire discount rate. The standard approach is to anchor on comparable public-company betas, unlever them to strip out the peer capital structure effects, then re-lever for your startup balance sheet and add a size and company-specific risk premium on top.

The result — commonly 20-35% for seed and Series A companies — reflects the real probability that the business may not reach the scale implied by its projections. That is not pessimism; it is the mathematically correct way to account for execution risk, key-person dependency, limited operating history, and illiquidity when discounting cash flows that may be five to ten years away.

A frequent objection: "VCs do not actually compute WACC, they use the venture capital method." Both approaches can be reconciled. The VC method embeds an explicit probability-of-failure adjustment in its target IRR; the WACC method treats expected cash flows on an unweighted basis with a high discount rate. Done correctly, they produce overlapping valuation ranges.

The adjusted WACC formula for startups

The WACC skeleton is the same, but each component requires a startup-specific approach:

WACC = (E/V) x Re + (D/V) x Rd x (1 - t)

Re = Rf + beta_startup x ERP + Size Premium + Company-Specific Risk Premium

beta_startup = beta_unlevered_peer x (1 + (1 - t) x (D/E)_startup)

Startup-specific adjustments:

Public-comp beta. Pick 3-5 public peers in the same sector, compute their unlevered betas, and average. Re-lever for your target capital structure.
Size premium. Add 3-6 percentage points based on the small-cap return premium documented in Duff & Phelps tables.
Company-specific risk premium. Add 2-5 percentage points for key-person dependency, single-product concentration, customer concentration, regulatory exposure, or limited operating history.
Market-value capital structure. Use the post-money valuation as the equity weight. Convertible notes count as debt at face value until conversion.
Effective tax rate often zero. Pre-revenue startups typically have no taxable income, so the tax shield on debt is moot during the early years.

Worked example: A late-stage payments company (Stripe-style)

Stripe is a useful late-stage growth-equity case study because it is private but heavily benchmarked. The numbers below are illustrative anchors for the WACC mechanics — not a forecast of Stripe valuation.

Public peers. Use ADYEN, NU, MELI, GPN, FIS, FI. Their levered betas average roughly 1.3-1.5. Unlevered betas (stripping out their modest leverage) average roughly 1.2-1.4.

Re-lever for the target. A mature payments company at scale often runs 10-20% debt. Assume 15% debt and 85% equity. Re-levered beta = 1.3 x (1 + (1 - 0.21) x (0.15 / 0.85)) = approximately 1.48.

Cost of equity (CAPM core). Rf = 4.2% (10Y Treasury normalized). ERP = 5.0%. CAPM Re = 4.2% + 1.48 x 5.0% = 11.6%.

Size premium. For a $50-100B late-stage private company, size premium is closer to mid-cap territory at 1-2%. Apply 1.5%.

Company-specific risk premium. Late-stage growth equity sits at the lower end of this band. Apply 1-2% for ongoing execution risk, IPO-timing risk, and customer concentration in the largest enterprise accounts.

Adjusted Re. 11.6% + 1.5% + 1.5% = approximately 14.6%.

Cost of debt. A late-stage company can typically access term debt at 7-9%. After tax at 21%, Rd_after_tax = 8% x 0.79 = approximately 6.3%.

WACC. 0.85 x 14.6% + 0.15 x 6.3% = 12.4% + 0.95% = approximately 13.4%. That sits comfortably in the typical late-stage growth-equity WACC range of 12-18%.

Worked example: A pre-revenue AI lab (OpenAI-style at seed scale)

For an early-stage AI company with no revenue, the mechanics are similar but the premiums balloon. Illustrative numbers only.

Re_CAPM_core = 4.2% + 1.5 (unlevered AI/software beta) x 5.0% = 11.7%. Add size premium of 6% (small-cap band). Add company-specific risk premium of 5% (single-product concentration, key-person dependency, regulatory uncertainty, undefined business model). Adjusted Re = 11.7% + 6% + 5% = approximately 22.7%. Since the company has no debt and no taxable income, WACC = Re = approximately 22.7%. That figure sits firmly inside the typical 20-35% seed range.

Run the calculation

The calculator below pre-fills capital structure data from any public peer ticker. For startups, enter a peer ticker first, then manually increase the cost of equity by your size and company-specific risk premia. Set the debt weight to zero (or low) and the tax rate to zero for pre-revenue startups. The output WACC plugs straight into a DCF model as the discount rate.

WACC Calculator (Weighted Average Cost of Capital)

Estimate a company’s blended cost of financing — the hurdle rate it must clear to create value. Pick a ticker to auto-fill capital weights, or sliders for cost of equity and debt.

Inputs

Pick a stock to auto-fill

Equity weight (%)80%

Debt weight (%)20%

Cost of Equity, Re (%)iCost of Equity (Re)Required return for equity holders. Often estimated via CAPM: Re = Rf + β·(Rm − Rf).

Cost of Debt, Rd (%)iCost of Debt (Rd)Effective interest rate the company pays on debt.

Tax Rate (%)

Result

WACC iWACC (Weighted Average Cost of Capital)A blended cost of financing across equity and debt, weighted by their share of total capital.WACC = (E/V)·Re + (D/V)·Rd·(1 − t)

7.83%

Around market

Adjust weights and rates

What this means. Typical for a US large-cap; ROIC must comfortably exceed this.

Equity weight (E/V)80.0%

Debt weight (D/V)20.0%

After-tax cost of debt3.16%

Reference

Term explanations

Every input and output on this page, explained in plain English. Hover the info icons in the calculator above to see the same content inline.

WACC (Weighted Average Cost of Capital)

A blended cost of financing across equity and debt, weighted by their share of total capital.

Formula

WACC = (E/V)·Re + (D/V)·Rd·(1 − t)

How to read the result

< 7

Low cost of capital5/5

Cheap funding base — easier to clear the hurdle.

7 – 10

Around market3/5

Typical for a US large-cap; ROIC must comfortably exceed this.

> 10

High cost of capital1/5

Expensive funding — requires high returns to create value.

Cost of Equity (Re)

Required return for equity holders. Often estimated via CAPM: Re = Rf + β·(Rm − Rf).

Cost of Debt (Rd)

Effective interest rate the company pays on debt.

Beta (β)

Sensitivity of the stock to overall market moves. Market β = 1.

FAQ

Frequently asked questions

It is the discount rate in DCF models and the hurdle rate ROIC must beat. Anything earned above WACC creates value; anything below destroys it.

Educational tool only. The outputs above are produced by a deterministic formula from the values you enter. They are not a recommendation to buy, hold, or sell any security and are not investment advice. Always do your own research and consider consulting a licensed advisor before making investment decisions.

Common mistakes when computing startup WACC

Using a public-comp WACC directly. Public peers carry far less execution risk than your startup. Without size and company-specific premia, the WACC is materially too low.
Skipping the unlever-relever step. A peer with high leverage has a different levered beta than its underlying business risk implies. Always unlever to asset beta, then re-lever for your structure.
Forgetting illiquidity. Private equity stakes are not freely tradable. The size premium partially captures this, but for very early-stage companies, an additional 1-3% illiquidity discount is appropriate.
Using book-value weights. The book value of a startup equity is often zero or negative. Always use the most recent post-money valuation as the equity weight.
Mixing the VC method and WACC inconsistently. Choose one. Either apply a high discount rate to expected cash flows (WACC method), or apply a moderate discount rate to probability-weighted cash flows (DCF with explicit failure scenarios).
Not declining WACC as the company matures. A Series C company should have a meaningfully lower WACC than a Series A company. Static WACC across funding rounds misrepresents the de-risking trajectory.
Ignoring convertible note interest. Even modest convertible note interest contributes to cost of debt during the period before conversion. Include it.

WACC Calculator for Startups

Why startup WACC is fundamentally different

The adjusted WACC formula for startups

Worked example: A late-stage payments company (Stripe-style)

Worked example: A pre-revenue AI lab (OpenAI-style at seed scale)

Run the calculation

WACC Calculator (Weighted Average Cost of Capital)

Term explanations

WACC (Weighted Average Cost of Capital)

Cost of Equity (Re)

Cost of Debt (Rd)

Beta (β)

Frequently asked questions

Common mistakes when computing startup WACC

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