The first ratios we'll take a look at in this tutorial are the liquidity ratios. Liquidity ratios attempt to measure a company's ability to pay off its shortterm debt obligations. This is done by comparing a company's most liquid assets (or, those that can be easily converted to cash), its shortterm liabilities.
In general, the greater the coverage of liquid assets to shortterm liabilities the better as it is a clear signal that a company can pay its debts that are coming due in the near future and still fund its ongoing operations. On the other hand, a company with a low coverage rate should raise a red flag for investors as it may be a sign that the company will have difficulty meeting running its operations, as well as meeting its obligations.
The biggest difference between each ratio is the type of assets used in the calculation. While each ratio includes current assets, the more conservative ratios will exclude some current assets as they aren't as easily converted to cash. The ratios that we'll look at are the current, quick and cash ratios and we will also go over the cash conversion cycle, which goes into how the company turns its inventory into cash.
CURRENT RATIO:
The current ratio is a popular financial ratio used to test a company's liquidity (also referred to as its current or working capital position) by deriving the proportion of current assets available to cover current liabilities.
The concept behind this ratio is to ascertain whether a company's shortterm assets (cash, cash equivalents, marketable securities, receivables and inventory) are readily available to pay off its shortterm liabilities (notes payable, current portion of term debt, payables, accrued expenses and taxes). In theory, the higher the current ratio, the better. Formula:

QUICK RATIO:
The quick ratio  aka the quick assets ratio or the acidtest ratio  is a liquidity indicator that further refines the current ratio by measuring the amount of the most liquid current assets there are to cover current liabilities. The quick ratio is more conservative than the current ratio because it excludes inventory and other current assets, which are more difficult to turn into cash. Therefore, a higher ratio means a more liquid current position.
Formula:

CASH RATIO:
The cash ratio is an indicator of a company's liquidity that further refines both the current ratio and the quick ratio by measuring the amount of cash, cash equivalents or invested funds there are in current assets to cover current liabilities.
Formula:

CASH CONVERSION CYCLE:
This liquidity metric expresses the length of time (in days) that a company uses to sell inventory, collect receivables and pay its accounts payable. The cash conversion cycle (CCC) measures the number of days a company's cash is tied up in the the production and sales process of its operations and the benefit it gets from payment terms from its creditors. The shorter this cycle, the more liquid the company's working capital position is. The CCC is also known as the "cash" or "operating" cycle.
Formula:

Components:
DIO is computed by:
1. Dividing the cost of sales (income statement) by 365 to get a cost of sales per day figure; 2. Calculating the average inventory figure by adding the year's beginning (previous yearend amount) and ending inventory figure (both are in the balance sheet) and dividing by 2 to obtain an average amount of inventory for any given year; and 3. Dividing the average inventory figure by the cost of sales per day figure. For Zimmer's FY 2005 (in $ millions), its DIO would be computed with these figures: (1) cost of sales per day  739.4 ÷ 365 = 2.0 
(2) average inventory 2005 536.0 + 583.7 = 1,119.7 ÷ 2 = 559.9 (3) days inventory outstanding 559.9 ÷ 2.0 = 279.9 
DIO gives a measure of the number of days it...