This all-in-one U.S. Government Travel Calculator provides tools for both quick cost and detailed travel estimates. To use it, first select a mode: use the "Simple Cost Estimator" by entering a destination, duration, and other known costs for a fast, high-level budget. For a detailed breakdown, select the "Complete Calculator" and navigate to the Per Diem tab to build a multi-leg itinerary and fetch official lodging/M&IE rates.
You can then use the Comp Time tab to input your normal work schedule and detailed flight itinerary to accurately calculate your creditable travel hours, or even send your official per diem itinerary directly over to the comp time calculator.
Update Notes: Added Rate Data Update Tracker for GSA and State Dept. Per Diem Rates