Federal GSA Per Diem Calculator

The U.S. Federal Government General Services Administration publishes official Lodging and Per Diem rates. The regulations about how to apply these rates are somewhat complex and easy to miscalculate. On this site there are calculators that help that process. The calculators automatically calculate adjustments for travel days, provided meals, and correct rates for the time of year. Typically, business offices ask that travellers do the calculation and print out a copy to hand in with a travel request/reimbursement.

Rates are updated by the GSA in mid-August, and I usually get them uploaded immediately after they do.