Pick a tool below. Each page includes the formula, step-by-step logic, and examples—so you can use the result with confidence.
Showing 5 tools
Subcategory
Calculate exact age from a birth date with optional as-of date. Fully client-side — no account, uploads, or remote storage.
Measure gaps between two calendar dates including leap years. Fully client-side — no account, uploads, or remote storage.
Find elapsed time between two clocks, optionally across midnight. Fully client-side — no account, uploads, or remote storage.
Convert epoch seconds or milliseconds to ISO dates and back with timezone context. Fully client-side — no account, uploads, or remote storage.
Convert a local datetime between IANA zones with DST rules explained. Fully client-side — no account, uploads, or remote storage.