Publication 915 is available on the Internal Revenue Service's website, IRS.gov. The publication includes worksheets and information to help filers determine whether Social Security benefits reported on Form SSA-1099 and Railroad Retirement Board benefits reported on RRB-1099 are taxable.
To complete the first worksheet in Publication 915 to figure taxable benefits, a taxpayer enters the total amount of his lump-sum benefits payments, payments reflected on Forms SSA-1099 and RRB-1099, taxable pension amounts, tax-exempt interest income and excluded income, and then he follows the calculation instructions. To determine whether his benefits are taxable, a taxpayer compares his worksheet totals to the base amount for his tax status, explains the Internal Revenue Service. The agency's website offers blank and sample completed worksheets.