Discounted Cash Flow (DCF) valuation estimates the intrinsic value of an investment based on its expected future cash flows. The core principle: a dollar today is worth more than a dollar tomorrow. Future cash flows are discounted back to their present value using a discount rate (WACC). This tool uses a two-stage model: an explicit forecast period with a higher growth rate, followed by a terminal value using a perpetual growth rate (Gordon Growth Model).

The Weighted Average Cost of Capital (WACC) typically ranges from 7% to 12% for stable large-cap companies, and higher for riskier small-caps or emerging markets. A common approach is to use 8–10% as a baseline. Factors influencing WACC include the risk-free rate, equity risk premium, beta, and the company's debt-to-equity ratio. When in doubt, 9% is a reasonable starting point for a mature US company.

The terminal growth rate represents the company's perpetual growth rate beyond the forecast period. It should generally not exceed the long-term GDP growth rate of the economy (typically 2–3% for developed markets). Using a rate above 4% is usually considered aggressive. A common practice is to use 2.5% as a conservative estimate. Remember: if the terminal growth rate approaches or exceeds the WACC, the model breaks down (infinite valuation).

Margin of Safety, popularized by Benjamin Graham, is the difference between a stock's intrinsic value and its current market price, expressed as a percentage of intrinsic value. A positive margin (e.g., 20%+) suggests the stock may be undervalued, providing a buffer against estimation errors. Many value investors look for at least a 20–30% margin of safety before investing.

DCF models are highly sensitive to assumptions—small changes in growth rates or discount rates can dramatically alter the result. Key limitations include: (1) difficulty forecasting cash flows far into the future, (2) reliance on a single terminal value that often represents 60–80% of total valuation, (3) sensitivity to WACC estimates, and (4) inability to fully capture qualitative factors like management quality or competitive moats. Always use DCF alongside other valuation methods.

The sensitivity table shows how the intrinsic value changes across a range of WACC and growth rate assumptions. This helps you understand the range of possible valuations and identify whether the stock is undervalued under most reasonable scenarios—or only under very optimistic ones. A wide dispersion suggests high uncertainty; a narrow range suggests more confidence in the valuation.

Neither is universally "better"—they serve different purposes. P/E ratios are quick, relative valuation tools that compare a stock to its peers or the market. DCF provides an absolute, intrinsic valuation based on the company's own fundamentals. DCF is more rigorous but requires more assumptions. Many professional investors use both: DCF for intrinsic value estimation, and multiples like P/E for sanity-checking against market comparables.