For example, if you wish to calculate a monthly average number of hours worked and use six months of data, divide the total hours your employee works in six months and divide the result by six to determine the monthly average hours of work for the employee.
Social Security disability payments may be includable in taxable income and still not increase the tax you pay. A lump-sum retroactive payment of Social Security Disability Insurance (SSDI) may be includable in taxable income, depending on the amount and your other income and deductions.
The amount of Social Security income which is taxable depends on your taxable income. Most high-income retirees will have 85% of Social Security benefits taxable. For lower-income retirees, less than 85% will be taxable, but many retirees in a 15% tax bracket will face a marginal tax rate much higher than 15%. Social security benefits are also taxable in some states (see Figure 1.)