Conception date from a last menstrual period or from a known due date, as ISO 8601 dates

Convert dates between Gregorian, Hebrew, Islamic and Chinese calendars; holidays by year.

Convert dates between 13 calendars and get Islamic, Jewish, Chinese and Persian holiday dates (Ramadan, Eid, Passover, Chinese New Year, Nowruz) for 1900-2100.

Antenatal visit dates from the WHO 2016, NICE or ACOG published schedules, as calendar dates.

Due date from last menstrual period using Naegele's rule, with 21-45 day cycle length correction.

Dating from BPD, HC, AC and FL measurements in millimetres, using Hadlock 1984 equations.

Pregnancy due date and gestational age API. EDD from LMP, conception, IVF transfer day, or ultrasound CRL. ACOG redating rules, trimester, and term milestones. Deterministic ISO 8601 dates.

Trimester boundaries, 24w0d viability, and four preterm and four term classes with their dates.

Due date from embryo transfer date. Day-3, day-5, day-6 and egg retrieval calculated separately.

Gestational age at any given date, returned as a 29w2d label and as total days.

Applies ACOG Committee Opinion 700 Table 1 to decide whether an ultrasound overrides LMP dating.

The Global Time API is a valuable resource that makes it easy for developers to access accurate and up-to-date time and date information for countries around the world.

Embark on a temporal journey with the World Time API – your global clock for instant access to the current date and time in any city. Seamlessly integrating with applications, this API synchronizes the world, ensuring users stay connected to the heartbeat of time across diverse corners of the globe.

The Global API delivers seamless date and business day calculations worldwide, catering to international business needs.

Ovulation estimate and 6-day fertile window from cycle length. Not contraceptive guidance.

Accurate business-day, holiday, and scheduling math for major countries and their subdivisions — without maintaining a single holiday calendar yourself. Add or subtract working days, check if a date is a business day, find the next valid date, or count working days between two dates, with full support for regional subdivisions, custom weekends, and your own blackout dates. One simple GET call, instant JSON.

Convert any date and time between world time zones with correct daylight saving handling, get the current time of any zone with its offset, or list every supported zone name. Daylight saving rules follow the standard worldwide zone database.

Calculate business days accurately while accessing global holiday data to optimize your workflows.

Get accurate timezone details, including DST offset and UTC offset, for any latitude and longitude location using the Global Timezone Locator API.

Efficiently retrieve timezone, UTC, and DST information for any latitude and longitude.

The Global Temporal Data API provides accurate time zone information with historical data for seamless integration of global applications.

Ensure timely project deliveries with the SLA Deadline Calculator, using global holidays for precise deadline calculations.

Trust our Reliable API for consistent date and business day calculations, ensuring you never miss a deadline again.

Libera.Date.Api is a high-precision date calculation engine designed to streamline business logic for global applications. Its core strength lies in its advanced Working Days System, which accurately calculates business days by automatically excluding weekends and public holidays for multiple countries (including 100 countries). Beyond simple duration checks, the API offers intelligent scheduling tools like finding the nearest available working day, analyzing date ranges for non-working intervals, and distinguishing between standard weekends and legal holidays. Whether you are computing SLAs, planning delivery windows, or building HR rosters, Libera.Date.Api ensures your dates align with real-world business calendars.

Enhance your scheduling with the Smart API, designed to simplify date and business day calculations with intelligence.