Doctors in the developing world measure their progress not by the aggregate number of children who die in childbirth but by the infant mortality rate, a ratio of the number of births to deaths.

Similarly, baseball’s leadoff batters measure their “on-base percentage” – the number of times they get on base as a percentage of the number of times they get the chance to try.

Acquirers also like tracking ratios and the more ratios you can provide a potential buyer, the more comfortable they will get with the idea of buying your business.

Better than the blunt measuring stick of an aggregate number, a ratio expresses the relationship between two numbers, which gives them their power.

If you’re planning to sell your company one day, here’s a list of seven ratios to start tracking in your business now:

1. Employees per square foot

By calculating the number of square feet of office space you rent and dividing it by the number of employees you have, you can judge how efficiently you have designed your space. Commercial real estate agents use a general rule of 175–250 square feet of usable office space per employee.

2. Ratio of promoters and detractors

Fred Reichheld and his colleagues at Bain & Company and Satmetrix, developed the Net Promoter Score® methodology, which is based around asking customers a single question that is predictive of both repurchase and referral. Here’s how it works: survey your customers and ask them the question “On a scale of 0 to 10, how likely are you to recommend <insert your company name> to a friend or colleague?” Figure out what percentage of the people surveyed give you a 9 or 10 and label that your ratio of “promoters.” Calculate your ratio of detractors by figuring out the percentage of people surveyed who gave you a 0–6 score. Then calculate your Net Promoter Score by subtracting your percentage of detractors from your percentage of promoters.

The average company in the United States has a Net Promoter Score of between 10 and 15 percent. According to Satmetrix’s 2011 study, the U.S. companies with the highest Net Promoter Score are:

USAA Banking 87%

Trader Joe’s 82%

Wegmans 78%

USAA Homeowner’s Insurance 78%

Costco 77%

USAA Auto Insurance 73%

Apple 72%

Publix 72%


Kohl’s 70%

3. Sales per square foot

By measuring your annual sales per square foot, you can get a sense of how efficiently you are translating your real estate into sales. Most industry associations have a benchmark. For example, annual sales per square foot for a respectable retailer might be $300. With real estate usually ranking just behind payroll as a business’s largest expenses, the more sales you can generate per square foot of real estate, the more profitable you are likely to be.

Specialty food retailer Trader Joe’s ranks among companies with the highest sales per square foot; Business Week