The following formula is involved in the calculation of sales to accounts payable ratios:

Sales to accounts payable ratio:
where S is the total amount of sales and AP is the accounts payable balance.

The following references can be used to cite this sales to accounts payable ratio calculator:
 Soper, D.S. (2017) "Sales to Accounts Payable Ratio Calculator (Online Software)", http://www.danielsoper.com/fincalc. 
 Siegel, J. and Shim, J. (1997). "Schaum's Quick Guide to Business Formulas", New York, NY: McGrawHill. 