Monroe Calculator
Determine the intrinsic value of a stock using the Monroe Method. Estimate future price and calculate a safe buy price with a Margin of Safety.
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Projected Value vs. Sticker Price Decay
| Year | Projected EPS ($) | Implied Stock Price ($) |
|---|
*Implied Stock Price assumes P/E expands/contracts linearly or stays constant to target.
What is the Monroe Calculator?
The Monroe Calculator is a specialized financial tool used by value investors to determine the intrinsic value of a company. Based on principles popularized by modern value investing strategies (often associated with the “Rule #1” investing style), this calculator helps investors decide whether a stock is currently undervalued or overvalued.
Unlike simple ratio comparisons, the Monroe Calculator projects the company’s future earnings based on its growth rate, assigns a future valuation, and then “discounts” that value back to today’s dollars using a required Minimum Acceptable Rate of Return (MARR). The result is a “Sticker Price” or fair value. To minimize risk, investors apply a “Margin of Safety” (typically 50%) to calculate the maximum entry price.
This tool is ideal for long-term investors looking to build wealth through fundamental analysis rather than short-term speculation. However, it relies heavily on the accuracy of the input assumptions regarding growth and market multiples.
Monroe Calculator Formula and Mathematical Explanation
The Monroe Calculator uses a multi-step compound interest and discounting formula. The logic follows the lifecycle of an investment over a 10-year horizon.
Step 1: Calculate Future Earnings Per Share (EPS)
First, we project the current earnings into the future using the estimated annual growth rate.
Future EPS = Current EPS × (1 + Growth Rate)^10
Step 2: Calculate Future Stock Price
Next, we estimate what the stock might trade for in 10 years by applying a future Price-to-Earnings (P/E) ratio to the Future EPS.
Future Price = Future EPS × Future P/E Ratio
Step 3: Calculate Sticker Price (Present Value)
We then determine what that future amount is worth today, assuming we want to earn our Minimum Acceptable Rate of Return (MARR) every year.
Sticker Price = Future Price / (1 + MARR)^10
Step 4: Calculate Margin of Safety (Buy Price)
Finally, we apply a safety factor to protect against errors in estimation.
Buy Price = Sticker Price × 0.50
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| Current EPS | Trailing 12-month Earnings Per Share | USD ($) | 0.10 – 50.00+ |
| Growth Rate | Expected annual compounding growth | Percent (%) | 5% – 25% |
| Future P/E | Multiple investors will pay for earnings | Ratio | 10 – 40 |
| MARR | Minimum Acceptable Rate of Return | Percent (%) | 12% – 15% |
Practical Examples (Real-World Use Cases)
Example 1: High-Growth Tech Company
Consider a technology firm that is growing rapidly but has a high current valuation. An investor wants to know if the current price of $150 is justified.
- Current EPS: $5.00
- Growth Rate: 20% (Aggressive)
- Future P/E: 40 (Expects high premium)
- MARR: 15%
Results:
- Future EPS (10 yrs): $30.96
- Future Stock Price: $1,238.35
- Sticker Price (Fair Value): $306.10
- Buy Price (MOS): $153.05
Interpretation: Even with aggressive assumptions, the intrinsic value is high. Since the current price ($150) is below the Buy Price ($153.05), this might be a valid purchase for a value investor.
Example 2: Stable Utility Company
A stable utility company is trading at $60. It grows slowly but consistently.
- Current EPS: $4.00
- Growth Rate: 5%
- Future P/E: 15
- MARR: 12% (Lower risk requirement)
Results:
- Future EPS (10 yrs): $6.52
- Future Stock Price: $97.78
- Sticker Price (Fair Value): $31.48
- Buy Price (MOS): $15.74
Interpretation: The calculator shows the stock is significantly overvalued based on earnings growth alone. The current price ($60) is far above the Sticker Price ($31.48), suggesting the market price may be driven by dividends or speculation rather than growth fundamentals.
How to Use This Monroe Calculator
- Enter Current EPS: Find the “EPS (TTM)” on any financial news site.
- Estimate Growth Rate: Look at historical equity growth or analyst estimates. Be conservative; if a company grew at 30% historically, consider inputting 15% or 20% to be safe.
- Set Future P/E: A common rule of thumb is to use the lower of: (a) the historical average P/E or (b) 2 times the growth rate.
- Define MARR: Enter your required return. 15% is the standard for beating the market significantly.
- Analyze Results: Look at the “Buy Price”. If the stock’s current market price is below this number, it offers a Margin of Safety.
Key Factors That Affect Monroe Calculator Results
Several financial levers can drastically alter the output of the Monroe Calculator:
- Growth Rate Sensitivity: Small changes in the growth rate compound over 10 years. Overestimating growth is the most common error leading to “value traps.”
- P/E Multiple Contraction: If you buy a stock when its P/E is 50, but it drops to a P/E of 20 in 10 years, your returns will be crushed even if earnings grow. Always assume P/E will revert to the mean.
- Interest Rates: Higher market interest rates generally lower P/E ratios across the board. In a high-rate environment, inputs for Future P/E should be conservative.
- Dividends: This calculator focuses on capital appreciation. For high-dividend stocks, the Total Return might be acceptable even if the Buy Price looks low here.
- Economic Moats: A company can only maintain high growth (e.g., 20%+) if it has a strong competitive advantage (moat). Without a moat, competition will erode margins and slow growth.
- Inflation: If inflation is high, future earnings are worth less. Your MARR should ideally be higher than the inflation rate plus a risk premium.
Frequently Asked Questions (FAQ)
No. It works best for consistent, profitable companies with predictable earnings. It is not suitable for pre-revenue startups, cyclical commodities, or banks (where book value is often a better metric).
15% is chosen to provide a significant buffer over the S&P 500’s historical average return (~10%). If you aren’t aiming to beat the market index, you might as well buy an index fund.
A negative P/E means the company has negative earnings (a loss). The Monroe Calculator cannot value companies with negative earnings; you must wait for profitability or use Price-to-Sales metrics.
Earnings Per Share (EPS) is preferred because it accounts for share buybacks or dilution. If a company grows net income but doubles its share count, your value per share drops.
It is the difference between the intrinsic value (Sticker Price) and the price you pay. It acts as a buffer against bad luck, bad timing, or bad assumptions.
Yes, though 10 years is standard for smoothing out business cycles. Shortening the timeframe makes the valuation more sensitive to the terminal P/E ratio.
Financial aggregators like Yahoo Finance, Morningstar, or Seeking Alpha list historical growth rates for revenue, EBITDA, and EPS.
No. The output represents the gross value of the asset. Capital gains taxes would apply upon selling the stock in the future.
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