Time & DateGenerated accuracy model review: 2026-05-06

Day of Week accuracy and testing

This page documents how Calwarden builds trust for this calculator: source notes, regression-style default tests, limitations, assumptions, unit handling, rounding, and visible change history.

Formula source

The calculator uses standard JavaScript date libraries which implement the Gregorian calendar rules. It determines the day index (0=Sunday, 1=Monday...) for the specific date entered.

Test cases

Default input regression check

Generated from the checked-in default inputs and calculate function.

Inputs

Select Date: 2000-01-01

Expected outputs

Day of Week: Saturday
Day of Year: 1

Known limitations

This page documents the checked-in calculator logic and does not certify results for every real-world edge case.
Use the result as a planning estimate unless the calculator page states a stricter purpose.

Assumptions

The calculator assumes the proleptic Gregorian calendar for all entered dates.
Weekday naming follows standard English locale formatting from the browser environment.
Day-of-year values reflect leap years automatically when applicable.

Unit handling

Select Date accepts calendar dates.

Rounding rules

Number displays use up to 2 decimal places in the calculator UI.

Version history

1.0.0 - 2026-05-06

Generated accuracy and testing page from the current day-of-week-calculator calculator definition.

Change log

2026-05-06

Published default regression test documentation and metadata fallbacks for Day of Week.

Calculator transparency

Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.

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