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

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

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

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

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

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

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.

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

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

Count working days between two dates or add business days to a date, skipping weekends and public holidays of 100+ countries and regions.

Get precise results every time with our Accurate API for calculating dates and business days—perfect for business professionals.

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

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

Automate age calculations for individuals or events, streamlining age-related tasks and ensuring precise date computations effortlessly.

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.

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

Automate age calculations for individuals or events, simplifying age-related tasks and ensuring accuracy in date calculations seamlessly.

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.

Automate age calculations for individuals or events, streamlining age-related tasks and ensuring precise date computations effortlessly.

Simplify the process of calculating age for people or events, improving the efficiency of age-related tasks while guaranteeing accurate date-based calculations with ease.

Calculates business days, SLA due dates, holiday-aware deadlines, skipped weekends and holidays, business hours, and business-time durations.

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

Simplify age calculations for individuals or events, making age-related tasks more efficient while ensuring accurate date-based computations with ease.

Utilize the DTSTART-based approach for effective recurrence management with our DTSTART Based Recurrence RRULE API.