Date calculator

Day of Week Calculator

Find the weekday for a date, or for a date plus a day offset.

Why offsets are useful

Offsets help answer questions such as "what weekday is 90 days from now?" without manually adding dates on a calendar. For business-day rules, holidays and local observances, use a calendar-specific system.

Example

May 17, 2026 is a Sunday. If you add a 10-day offset, the calculator moves to May 27, 2026 and reports the weekday for that resulting date.

Common mistakes

Do not use a weekday result alone for legal deadlines, travel schedules or business-day rules. A date can fall on a weekend or holiday even when the elapsed-day arithmetic is correct.

Limitations

This calculator uses calendar dates, not local civil-time rules for every location. It does not adjust for holidays, business closures or special regional calendars.

Last reviewed: 2026-05-17

Before relying on this result

Use this calculator together with the formula, assumptions, limitations and examples on the page. If the topic involves health, tax, lending, investment, legal, safety or current-rate decisions, treat the number as an estimate and check the relevant primary source or professional guidance.

Calculator metadata last reviewed: 2026-05-14.