940 is Federal Unemployment Tax (FUTA), filed annually. All paid by the employer. Deductible by the employer.

941 is quarterly federal payroll tax return. It reports employer and employee shares of Social Security and Medicare taxes and federal withholding tax. The Employer share of Social Security and Medicare tax is deductible by the employer.

Medicare tax paid by the employer is 1.45% of Medicare wages. Social Security tax is 6.2% of Social Security wages. Note that Social Security wages and Medicare wages may not be the same as total wages.