Methodology

Lodging and M&IE come from the GSA Per Diem API (api.gsa.gov/travel/perdiem/v2) for FY2026 CONUS non-standard areas, with standard CONUS fallback ($110 lodging / $68 M&IE per FTR Bulletin 26-01). Mileage rates come from the IRS standard mileage rate tables (see our mileage calculator for the current cited notice).

What GSA publishes vs what we compute

• GSA publishes NSA destinations, seasonal lodging, M&IE tier totals, and the ZIP→destination index.
• We compute first/last-day M&IE at 75% of the daily tier, trip totals from nights + M&IE + mileage, and client-side location resolution.
• We do not invent rates, seasons, or county membership beyond GSA’s published fields.

ZIP-mapping transparency

When you enter a ZIP, we report GSA’s ZIP-to-destination mapping and, separately, the NSA’s published county/area string as the rate basis. We do not claim the typed ZIP was verified to lie inside a specific county beyond what GSA’s ZIP feed provides (standard-rate ZIPs have no county name in that feed).

Refresh cadence

• Annual: mid-August GSA FY announcement / Oct 1 fiscal-year cutover.
• As-needed: mid-year GSA or IRS updates (e.g. mileage-rate notices).

Publisher: BlackStack Systems