1. Enter the symbol for the company in which you are interested.
2. Enter the return(ROI) which you expect to see and the period(in years) which you expect to realize it.
3. Click "update" to update the data.
4. Check your Rule 1 calculation settings.
5. Leave the overrides empty/blank to use the calculated results, or enter a value to override the calculated values.
6. Click "calcuate".
Rule 1
Data Source
Extracted Data
Sticker Price:
EPS Growth:
Future EPS:
Future Worth:
Growth Rate Calculation:
EPS Growth Rate Calculation:
Override EPS Growth Rate:
Override PE Ratio:

This is my attempt at a simple MOS or margin of safety calculator. I got tired of manually updating the numbers when the financials were updated, so instead created this automatic Rule #1 calculator. It finds what data it can from MSN Money, calculates the values it needs (as in cash, equity, debt, average PE) then calculates an estimated growth rate. This information is then used to do a future worth calculation, which is then reversed to do a future value/present worth calculation. This provides the sticker price, and then a simple 50% MOS is calucated from there.
This page is in the initial beta phase of development for a Rule #1 calculator but is in a state in which it is usable. The content on this page is driven by data collected from MSN's Money website. Occasionally the frames containing the MSN page(s) may fail to load properly. You may either try to reload the entire page or just the frames that did not load correctly. The calculations are not computed until the "Calculate" button is clicked, and will not be successfull if the data pages from msn have not finished loading correctly. MSN occasionally changes the structure of their pages which will break this calculator. When I notice this I will make an attempt to correct the problem. This page has only been tested to work on FF, IE, and Chrome. You do need to have javascript enabled for this page to work correctly.


Symbol: The stock symbol for the company to be evaluated.
ROI: Your expected return on investment.
Period: The period in which you expect to see your ROI.
Update: Click to reload or change the data for the selected stock.
Sticker Price: The present calculated worth for a single share of the company of interest. Based on a future value, present worth calculation.
MOS: The margin of safety, roughly 50% of the sticker price, built in to make sure the company is bought at a significantly lower cost then its actual worth.
EPS: Earnings Per Share.
EPS Growth: The expected/calculated growth rate for the company and its EPS.
Future EPS: The calculated feature value of the EPS, using a future value calculation.
PE: The calculated Price to Earnings ratio being used to determine sticker price.
Future Worth: The calculated (PE * Future EPS) future worth of the company at the end of the defined period.
Growth Rate Calculation: The algorithm to use when calculating the growth rates.
Since Year: Growth rate is calculated based on current year performance compared to year N, where N is the year in question.
Year/Year: Growth rate is calculated based on a year over year performance (year N compared to year N + 1).
EPS Growth Rate Calculation: The algorithm to use when calculating the EPS growth rates.
The calculated value will be compared to the "professionals" estimate and the lower of the two shall be used.
Simple Avg.: A simple average of all available growth rates.
1YR Weighted: An average of all available growth rates, with the most recent year performance weighted more heavily.
Last 5yrs.: An average of the growth rates from the most recent 5 years.
Override EPS Growth Rate: The growth rate in % to be used instead of the calculated or professional growth rate. Leave blank to use calculated value.
Override PE Ratio: The PE Ratio to be used instead of the calculated PE ratio. Leave blank to use calculated value.
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