Per diem rates with sources and dates

About DiemWise

Last updated 2026-10-24

DiemWise is a set of per diem calculators. Each page does one job and works straight away: you pick a place and the dates of a trip and get the rate and the total, with the source and the date of every number shown.

How it works

  • The calculations run in your browser. What you type or choose in a calculator stays on your device. The page only downloads the public rate tables.
  • Every number has a source. The Sources and dates page lists each data set with its effective date, its expiry and the day we last checked it. A page warns you when its rates have expired.
  • Results are computed, not typed in. The examples on each page are produced by the same code the calculator runs, and the code is tested against totals worked out by hand and against the examples in the official letters.
  • Third-party material used on the site is listed on the credits page.

Pro and the apps

The calculators on this site are free. We are building DiemWise Pro and DiemWise apps for phones and desktops with multi-country trips, DATEV and CSV export and reports. You can leave your email on a calculator page to hear once when Pro opens.

Who runs it

DiemWise is owned and operated by SKYSEED TECH LLC. You can write to us at support@diemwise.com.

Not affiliated, not tax advice

DiemWise is not affiliated with, endorsed by or sponsored by the U.S. General Services Administration (GSA), the Internal Revenue Service (IRS), the U.S. Department of Defense, or the German Federal Ministry of Finance (BMF). Their names are used only to say where a rate comes from. DiemWise does not give tax advice: it applies published rates and rules to the dates you enter, and your own case may differ. Ask a tax professional.

Advertising

The site is free to use. We may show advertising in future to pay for hosting and development. If we do, ads will be labelled “Advertisement”, will never cover a tool, and are described in the privacy policy.