What is the most important financial ratio?

Price Ratios

Price ratios are used to get an idea of whether a stock's price is reasonable or not. They are easy to use and generally pretty intuitive, but do not forget this major caveat: Price ratios are "relative" metrics, meaning they are useful only when comparing one company's ratio to another company's ratio, a company's ratio to itself over time, or a company's ratio to a benchmark. 

1) Price-to-Earnings Ratio (P/E) 

What you need:     Income Statement, Most Recent Stock Price

The formula:         P/E Ratio = Price per Share / Earnings Per Share

What it means:     Think of the price-to-earnings ratio as the price you'll pay for $1 of earnings. A very, very general rule of thumb is that shares trading at a "low" P/E are a value, though the definition of "low" varies from industry to industry. 

[InvestingAnswers Feature: The P/E Ratio -- A True Measure of Profits?]

2) PEG Ratio

What you need:     Income Statement, Most Recent Stock Price

The formula:         PEG Ratio = (P/E Ratio) / Projected Annual Growth in Earnings per Share 

What it means:      The PEG ratio uses the basic format of the P/E ratio for a numerator and then divides by the potential growth for EPS, which you'll have to estimate. The two ratios may seem to be very similar but the PEG ratio is able to take into account future earnings growth. A very generally rule of thumb is that any PEG ratio below 1.0 is considered to be a good value.

3) Price-to-Sales Ratio

What you need:     Income Statement, Most Recent Stock Price

The formula:         Price-to-Sales Ratio = Price per Share / Annual Sales Per Share

What it means:      Much like P/E or P/B, think of P/S as the price you'll pay for $1 of sales. If you are comparing two different firms and you see that one firm's P/S ratio is 2x and the other is 4x, it makes sense to figure out why investors are willing to pay more for the company with a P/S of 4x. The P/S ratio is a great tool because sales figures are considered to be relatively reliable while other income statement items, like earnings, can be easily manipulated by using different accounting rules. 

4) Price-to-Book Ratio (P/B) 

What you need:     Balance Sheet, Most Recent Stock Price

The formula:          P/B Ratio = Price per Share / Book Value per Share    

What it means:      Book value (BV) is already listed on the balance sheet, it's just under a different name: shareholder equity. Equity is the portion of the company that owners (i.e. shareholders) own free and clear. Dividing book value by the number of shares outstanding gives you book value per share.

Like P/E, the P/B ratio is essentially the number of dollars you'll have to pay for $1 of equity. And like P/E, there are different criteria for what makes a P/B ratio "high" or "low." 

[InvestingAnswers Feature: Don't Be Misled By the P/E Ratio]

5) Dividend Yield

What you need:     Income Statement, Most Recent Stock Price

The formula:          Dividend Yield = Dividend per Share / Price per Share

What it means:      Dividends are the main way companies return money to their shareholders. If a firm pays a dividend, it will be listed on the balance sheet, right above the bottom line. Dividend yield is used to compare different dividend-paying stocks. Some people prefer to invest in companies with a steady dividend, even if the dividend yield is low, while others prefer to invest in stocks with a high dividend yield.

[InvestingAnswers Feature: Decoding the Dividend Yield Formula]

6) Dividend Payout Ratio

What you need:     Income Statement

The formula:          Dividend Payout Ratio = Dividend / Net Income

What it means:      The percentage of profits distributed as a dividend is called the dividend payout ratio. Some companies maintain a steady payout ratio, while other try to maintain a steady number of dollars paid out each year (which means the payout ratio will fluctuate). Each company sets its own dividend policy according to what it thinks is in the best interest of its shareholders. Income investors should keep an especially close eye on changes in dividend policy. 

__________________________________________________________________

Profitability Ratios

Profitability ratios tell you how good a company is at converting business operations into profits. Profit is a key driver of stock price, and it is undoubtedly one of the most closely followed metrics in business, finance and investing. 

7) Return on Assets (ROA)

What you need:     Income Statement, Balance Sheet

The formula:         Return on Assets =  Net Income / Average Total Assets

What it means:      A company buys assets (factories, equipment, etc.) in order to conduct its business. ROA tells you how good the company is at using its assets to make money. For example, if Company A reported $10,000 of net income and owns $100,000 in assets, its ROA is 10%. For ever $1 of assets it owns, it can generate $0.10 in profits each year. With ROA, higher is better.

8) Return on Equity (ROE)

What you need: Income Statement, Balance Sheet

The formula: Return on Equity = Net Income / Average Stockholder Equity        

What it means: Equity is another word for ownership. ROE tells you how good a company is at rewarding its shareholders for their investment. For example, if Company B reported $10,000 of net income and its shareholders have $200,000 in equity, its ROE is 5%. For every $1 of equity shareholders own, the company generates $0.05 in profits each year. As with ROA, higher is better.

9) Profit Margin

What you need: Income Statement

The formula: Profit Margin = Net Income / Sales        

What it means: Profit margin calculates how much of a company's total sales flow through to the bottom line. As you can probably tell, higher profits are better for shareholders, as is a high (and/or increasing) profit margin.   

__________________________________________________________________

Liquidity Ratios

Liquidity ratios indicate how capable a business is of meeting its short-term obligations. Liquidity is important to a company because when times are tough, a company without enough liquidity to pay its short-term debts could be forced to make unfavorable decisions in order to raise money (sell assets at a low price, borrow at high interest rates, sell part of the company to a vulture investor, etc.). 

10) Current Ratio

What you need: Balance Sheet

The formula: Current Ratio = Current Assets / Current Liabilities        

What it means: The current ratio measures a company's ability to pay its short-term liabilities with its short-term assets. If the ratio is over 1.0, the firm has more short-term assets than short-term debts. But if the current ratio is less than 1.0, the opposite is true and the company could be vulnerable to unexpected bumps in the economy or business climate. 

11) Quick Ratio 

What you need: Balance Sheet

The formula: Quick Ratio = (Current Assets - Inventory) / Current Liabilities        

What it means: The quick ratio (also known as the acid-test ratio) is similar to the quick ratio in that it's a measure of how well a company can meet its short-term financial liabilities. However, it takes the concept one step further. The quick ratio backs out inventory because it assumes that selling inventory would take several weeks or months. The quick ratio only takes into account those assets that could be used to pay short-term debts today. 

__________________________________________________________________

Debt Ratios

These ratios concentrate on the long-term health of a business, particularly the effect of the capital and finance structure on the business:   12) Debt to Equity Ratio    What you need: Balance Sheet   The formula:  Debt-to-Equity Ratio = Total Liabilities / Total Shareholder Equity   What it means: Total liabilities and total shareholder equity are both found on the balance sheet. The debt-to-equity ratio measures the relationship between the amount of capital that has been borrowed (i.e. debt) and the amount of capital contributed by shareholders (i.e. equity). Generally speaking, as a firm's debt-to-equity ratio increases, it becomes more risky because if it becomes unable to meet its debt obligations, it will be forced into bankruptcy.    13) Interest Coverage Ratio   What you need: Income Statement   The formula:  Interest Coverage Ratio = EBIT / Interest Expense   What it means: Both EBIT (aka, operating income) and interest expense are found on the income statement. The interest coverage ratio, also known as times interest earned (TIE), is a measure of how well a company can meet its interest payment obligations. If a company can't make enough to make interest payments, it will be forced into bankruptcy. Anything lower than 1.0 is usually a sign of trouble.     Efficiency Ratios   These ratios give investors insight into how efficiently a business is employing resources invested in fixed assets and working capital. It's can also be a reflection of how effective a company's management is.    14) Asset Turnover Ratio   What you need: Income Statement, Balance Sheet   The formula: Asset Turnover Ratio = Sales / Average Total Assets   What it means: Like return on assets (ROA), the asset turnover ratio tells you how good the company is at using its assets to make products to sell. For example, if Company A reported $100,000 of sales and owns $50,000 in assets, its asset turnover ratio is 2x. For ever $1 of assets it owns, it can generate $2 in sales each year.    15) Inventory Turnover Ratio    What you need: Income Statement, Balance Sheet   The formula: Inventory Turnover Ratio = Costs of Goods Sold / Average Inventory   What it means: If the company you're analyzing holds has inventory, you want that company to be selling it as fast as possible, not stockpiling it. The inventory turnover ratio measures this efficiency in cycling inventory. By dividing costs of goods sold (COGS) by the average amount of inventory the company held during the period, you can discern how fast the company has to replenish its shelves. Generally, a high inventory turnover ratio indicates that the firm is selling inventory (thereby having to spend money to make new inventory) relatively quickly.   To learn more about financial ratios see these articles: Stock Screeners: The Best Way to Kick Start Your Investment Research; How to Common Size Financial Statements.