About Onesheet
Onesheet prints a whole-year calendar with holidays on a single page, or saves it as a PDF or image. There is no sign-up and no advertising inside the files.
Who makes it
Onesheet is made and run by Lumen Lab, a one-person studio. More apps and tools are at Lumen Lab. Contact: woxocoso@gmail.com.
Where the holidays come from
- United States: the federal holidays set by 5 U.S.C. 6103, including the observed weekday when a holiday falls on a weekend. The official schedule is published by the U.S. Office of Personnel Management.
- South Korea: computed from the Regulations on Holidays of Government Offices as amended on April 30, 2026, and checked date by date against the official tables for 2026 and 2027. 2028 uses astronomical almanac data published before the official notice, and 2029 and 2030 are projections from the rules.
- Election days and one-off holidays cannot be computed, so only confirmed dates are included.
Week numbers and lunar dates
Monday-start calendars use ISO 8601 week numbers. Sunday-start calendars count from the week containing January 1. Korean lunar dates follow a table based on Korea Astronomy and Space Science Institute data for 1912 to 2049, cross-checked against an independent astronomical calculation.
How results are checked
Weekdays are tested for every day from 1900 to 2100, and week numbers, month grids and holiday lists are compared automatically with independent references. If you find a mistake, please email us.
Your data
Calendars are made inside your browser. Your settings and files are not sent anywhere. See the privacy policy.