What to notice
Summary
Perdiemus is a web application that calculates U.S. Government Per Diem lodging rates. It allows travelers to look up the maximum allowable lodging reimbursement rate for a given location (by name or ZIP code) and date range, with support for custom sliding scale multipliers. The project acts as a practical calculator on top of public GSA (General Services Administration) per diem datasets.
Target audience
This tool is built for U.S. government travelers, contractors, and military personnel who need to quickly calculate per diem lodging reimbursement rates. It's also useful for travel administrators, finance teams, and anyone who needs to budget travel expenses within federal guidelines. AI developers and agents can also use it programmatically via the MCP server.
Key features
- Location selection from a comprehensive dropdown of over 200 U.S. cities and regions
- ZIP code lookup as an alternative to location selection
- Date range picker for arrival and departure day
- Optional daily breakout to see per-day rate details
- Custom sliding scale multiplier (e.g., (1,30,1),(31,120,0.75)) for extended stays
- Dark/Light theme toggle with system preference detection
- Google Analytics and Umami analytics integration
- Public MCP (Model Context Protocol) server for AI agent integration
- Responsive design using Bootstrap
Pain points
- Government per diem rates are scattered across multiple datasets and hard to look up quickly
- Travelers and contractors need to manually calculate lodging reimbursements, leading to errors
- Extended stays often have reduced rates, but the sliding scale rules are non-trivial to compute
- ZIP-based rate lookup is not always straightforward
- Existing GSA tools can be clunky and outdated
Usage instructions
Select a location from the dropdown (or enter a ZIP code), pick arrival and departure dates, optionally check 'Daily breakout' for a day-by-day view, and optionally enter a custom sliding scale multiplier for extended stays. Click 'Calculate' to see the maximum lodging rate the published GSA rates allow for that stay.