Time & Date tool map
Dates & calendars
Dates, weekdays, ages, and calendar intervals.
Choose the tool whose inputs and output match your task. Check each calculator’s assumptions and limitations before using its result.
Age Calculator
Calculate exact age in years, months, and days from a birth date to any age-at date, plus total months, weeks, days, weekday born, and next birthday.
Gestational Age Calculator
Estimate gestational age in weeks and days, due date, trimester, conception date, milestones, and prenatal timing from LMP, conception, or ultrasound dating.
Julian Date Converter
Convert mixed-calendar civil UTC dates to astronomical Julian Date forms, or convert a Julian Date back to UTC.
Pregnancy Conception Calculator
Estimate a likely conception date, possible conception range, and due date from an estimated due date, last period, cycle length, or ultrasound dating.
Reverse Due Date Calculator
Work backward from a pregnancy due date to estimate last menstrual period, likely conception timing, trimester boundaries, milestones, and appointment windows.
Time Card Calculator
Calculate weekly time card hours, regular hours, overtime hours, and unpaid lunch deductions for selected workdays.