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📅 Date Calculator

Calculate date differences, date offsets, business-day offsets, and lookup ISO week, quarter, leap year, lunar, zodiac, and solar-term details.

Business-day mode skips Saturdays and Sundays. Date Lookup provides a full date profile including ISO week, season, DST, and Chinese lunar calendar info.
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Calculate date differences, add or subtract offsets, shift by business days, and inspect date details such as ISO week number, quarter, season, leap year, DST, Chinese lunar calendar, zodiac, and solar terms. Useful for project schedules, milestone back-planning, contract periods, and everyday date math. Input dates and results are processed in the current browser and are not uploaded to LittleOne Tools servers. Business-day mode skips Saturdays and Sundays by default.