You can find M&IE rates for prior years at https://www.gsa.gov/travel/plan-book/per-diem-rates NB: Link allows you to select FY and location by ZIP; Charts include CONUS and Overseas locations.
However, if you're a W-2 employee, don't bother for 2018; That employee deduction was eliminated.
M&IE rates Only can be used for DOT rates; Lodging expenses must be actual, based on itemized billing.
