Midpoint of a salary range is calculated by different formulae based on the minimum or maximum salary and range spread, explains Fox Lawson and Associates for HRPeople. Using a salary minimum, the formula is (((2+RS)/2) x (1+RS)) x Salary Minimum, where "RS" is the salary range, a percentage and decimal.

For example, if the salary minimum is $10,000, and the salary range is 20 percent, then the formula is calculated as: (((2+0.2)/2) x (1+0.2)) x 10000. When calculated, it yields a salary midpoint of $13,200.

If the salary maximum is known, then the formula is: ((1/(1+RS)) x ((2+RS) / ((2+(2xRS))))). For example, if the salary maximum is $20,000, and the salary range is 20 percent again, then the formula is calculated as: ((1/(1+0.2)) x ((2+0.2) / ((2+(2x0.2))))) x 20000. This yields a salary midpoint of $15,283.33.