Easy analysis... Take Tax owed / Taxable income for each year. This will give you her effective tax rate. Take both effective tax rates * current year taxable income and see the tax savings. The analysis is not perfect because tax rates are progressive. It's possible that her taxable income jumped dramatically and much of her income is being taxed in higher tax brackets. I am interested in any analysis of the effect in high tax states and high mortgage areas. In Theory, the limiting of SALT deductions could cause a higher effective tax rate, but the lowering of the rates themselves should offset the lost SALT. I have not yet seen a higher tax rate for 2018, due to SALT, but it's possible. 30+ yrs VP Finance, CFO, Controller, CPA